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Credit: Sarah Wittmer
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In footnotes or endnotes please cite AIP interviews like this:
Interview of Wick Haxton by David Zierler on March 16, 2021,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
For multiple citations, "AIP" is the preferred abbreviation for the location.
Interview with Wick Haxton, professor of physics at UC Berkeley. Haxton recounts his childhood in Santa Cruz and his early interests in math and science. He describes his undergraduate education at the newly created UC Santa Cruz where his initial interest was in mathematics before he was given the advice that he did “mathematics like a physicist.” Haxton discusses his graduate work at Stanford where his original intent was to study general relativity before he connected with Dirk Walecka and Bill Donnelly to focus on nuclear theory and dense nuclear matter. He discusses his postdoctoral research at the University of Mainz where he concentrated on photo-pion physics during the early days of chiral perturbation theory, and he explains the opportunities that led to his next appointment at the LAMPF facility at Los Alamos. Haxton emphasizes the excellence of both his colleagues and the computational capacity at the Lab, and he describes his faculty appointment at Purdue and the solar neutrino experiment he contributed to in Colorado. He explains the opportunities that led to him joining the faculty at the University of Washington where the DOE was about to fund the Institute for Nuclear Theory. Haxton explains the “breakup” between nuclear theory and particle theory and how the INT addressed that. Haxton discusses the opportunities afforded at the INT to engage in nuclear astrophysics and he explains the rise and fall of the Homestake DUSEL project. He explains his decision to go emeritus at UW and to join the faculty at UC Berkeley and to be dual hatted at the Berkeley Lab, and he describes his tenure as department chair. At the end of the interview, Haxton describes his current work organizing the new Physics Frontier Center and the challenges presented by the pandemic, and he credits his formative time as Los Alamos for the diverse research agenda he has pursued throughout his career.
Okay. This is David Zierler, oral historian for the American Institute of Physics. It is March 16, 2021. I am so happy to be here with Professor Wick Haxton. Wick, it’s great to see you. Thank you for joining me.
Thank you. My pleasure.
All right. So, to start, first and most important question: Is Wick your given name or a nickname?
It’s actually my given name. [Chuckles]
What is the story behind that?
I think there was a branch of our family based in Great Britain that had the last name of Wycks, so my mother just varied that theme a little bit. [Chuckles]
And you’ve never had any nicknames because it’s sort of like a built-in nickname.
That’s right, and I’ve always…People tell me things like my name sounds like I should be in the rodeo or something of that sort. [Laughing]
Well, on a more official level, what is your title and institutional affiliation?
I’m a Professor of Physics at Berkeley. I’ve been there for about, I guess, 12 years now, and I am also an Emeritus Professor at the University of Washington where I spent about 25 years.
What were the circumstances of going emeritus in Washington and coming over to Berkeley?
Oh, it’s somewhat complicated. I almost moved to Berkeley around 1990. In fact, I accepted the offer [chuckles], but things got a little confused then because that was just at the time the Institute for Nuclear Theory was approved for the University of Washington. So, I became really worried that if I left, since I was very much a sparkplug of that effort, that it could jeopardize the INT. So that, plus the fact that my family situation then was complicated with kids in school and so forth, eventually led to me backing out. I still remember that Berkeley was incredibly graceful about letting me do that.
So, years later, after I finished 15 years as INT director, I stepped down. I was thinking, “This would be a great time to do something different. I’m pretty old, but I think I’d still like to try a few new things.” A couple of my friends had left the University of Washington then, and I just happened to have a chance interaction with Chuck Shank, who used to be director of LBL, at a committee meeting, and he told me how much they needed me back then and how disappointed he was that I didn’t come to Berkeley because LBL and the campus were working together on areas of interest to me, like neutrino physics. I thought about that for a day or two, and then I called up my friend Stuart Freedman and said, “You know, this would be a really good time for me to move to try something new. I’ve finished everything I wanted to do up here at the UW, and it would be good to try to do some new things where especially LBL with all its computing power could be helpful.” Then things took off from there and we made the move about a year later.
What was the idea between gaining the emeritus distinction? As a relatively young guy, that seems kind of unique. Why not just a transfer to Berkeley?
Well, thank you. I’m not sure that that’s completely true [laughs], but after 25 years I was qualified to be an emeritus professor, and it’s actually been nice. I kept connections with the UW. It’s actually good to have two academic homes. I do think of the UW and especially the INT as a second home. During my first few years at Berkeley, I spent quite a bit of time back in Seattle. In fact, that was part of the arrangement, that I could spend summers with my Seattle collaborators and so forth. Actually, this year, because of COVID-19, we’ve kind of gone to a new pattern where I spent most of the year up in Seattle…mostly for COVID-19 reasons, but nevertheless, it still feels a little bit like home. So, we’re very blessed. We love the West Coast and we (my wife Laura and I) have had an opportunity to live in the San Francisco/Berkeley area and to live in Seattle, two terrific cities.
Two terrific cities, indeed.
It’s kind of funny. You kind of hate to give up either one. [Chuckles]
That’s a great segue to my next question, which is very much an in-the-moment question. On the professional side in dealing with the pandemic, how has your science been affected, perhaps for better and/or worse?
Yeah. I really…I very much miss the in-person meetings that I thrive on, especially the hallway conversations with old friends about what they’re doing and what I’m working on. I feel that that’s been lost with the COVID-19 era, so I am very anxious to get back into the old mode to the extent that we can.
I also think it’s been a little bit difficult on some of the young people, students and post-docs, so I have the odd situation now that I’ve hired post-docs and am getting them started, but I’ve never actually met them in person. So, I do think that affects personal interactions that are important to science. It depends very much on the personalities of the people who are involved. You know, some students have thrived in the Zoom era and some, I find, I have to work harder to draw out. So, I do think there are some long-term implications of doing science remotely like this.
Fortunately, though, as a theoretician, the COVID-19 impact has been much, much less severe than in the case of experiment. Some of the obstacles my experimental colleagues are facing have prevented students from accessing the laboratory and delayed theses and things of this sort. So, I’m relatively fortunate being a theoretician in that we can cope with or address most of the obstacles that come up from having to do everything remotely.
On that latter point, of course it’s a caricature of theoreticians that sometimes you like nothing more than to be left alone in a room with a pen and a pad, and so on that basis, I’m curious if there have been any theoretical problems that you might have had more bandwidth to deal with over the past year.
Well, you know, I’ve actually in some ways…I think it’s the reverse. Theoretically you’re right. It seems like you’re holed up at home with all kinds of time and you can just work away, but I have found that my time is just filled up with Zoom meetings. I think there’s less of a barrier to setting up meetings now than there was when it was a matter of coming to my office.
For example, just less than a year ago I stepped down as chair at Berkeley, and you know, it was a help to have a bit of a physical barrier to limit meetings…Somebody had to find me either in my chair’s office, in my LBL office, or in my physics office, so one had to work a little bit to get that meeting with me. I think therefore if a matter wasn’t really all that important, it would get addressed by an email rather than an in-person meeting.
Now almost any issue that comes up, even if it’s relatively trivial, can be the source of yet another Zoom meeting. [Chuckles] So, I get up in the morning and I look at my calendar and it’s often just back-to-back Zoom meetings, and I’m not sure I’m all that productive. So, I’m in the same old mode of having too little time for the theoretical physics I want to do. I’ve always been kind of a hands-on theoretician. I’m not good at directing research; I have to be involved myself. A lot of it is done after dinner. [Chuckles] That’s when it’s quiet and I don’t have to worry about meetings.
Wick, on that point, going back to when you were chair of the department, it was on that basis that almost a year ago to the day—it was March 24, 2020—when I got in contact with you…
…with the idea that we would be all remote working for maybe a couple of weeks, and wouldn’t it be great if I could interview some eminent emeritus professors? You responded graciously and you gave me the great idea to interview Mary K., Marvin Cohen, and John Clarke.
In many ways, that really supercharged a project that continues to this day where I’m still interviewing eminent physicists over Zoom.
That’s terrific. The legacy at Berkeley is something we need to preserve, so I’m very grateful to you for doing that.
And here we are a year later. We’re still doing it. [Laughs]
Wick, let’s take it all the way back to the beginning. Let’s start first with your parents. Let me know a little bit about them and where they’re from.
Yeah. My father grew up in Iowa. He was in a farming family. In fact, after his father passed away, he took over the family farm. He had a sister and two brothers, but he was the one most interested in farming, so he bought out his siblings and took over the running of the farm. This was about a half section, about a 300-acre farm in Iowa. It was near the little town of Dexter. It’s about, oh, 20 miles south and a little bit west of Des Moines. So, he did that until World War II arrived. He was 4-F, but he managed finally to get into the Army. He had flat feet, but they became desperate enough they finally accepted him.
So, he went off to fight in the war in Europe. Of course, for a farmer it was pretty tough because you have all this equipment and investment, so he basically sold all of his equipment, went off to war, years later came back, and believe it or not, went back to the farm as a single guy after seeing Paris, I guess [laughs], still managing to enjoy the farming life. But this convinced his sister (my aunt), that my father was crazy. After the war there was no excuse for not knowing that there was more than just Dexter, Iowa, and yet he went back to this life on the farm.
Then, to our great fortune, he married my mother. She was not interested in living in Iowa. The family knew a little bit about California. I think my father’s parents had moved out there in retirement.
Where was your mother from?
My mother was born in Seattle, and she saw a lot of the country as she grew up, as her mother was a very specialized nurse who helped people with substance abuse problems. She was often contracted by a family to help a family member, and would need to move to take on the assignment. So, they traveled a lot. She had a fairly hard time as a young woman and as an older teen because of the Depression. Both of my parents went through the Depression, but it was much more difficult, I think, for my mother. My father was relatively prosperous living on a farm.
Neither one of my parents finished college. They both attended, but neither one graduated for somewhat different reasons. I think with my mother it was primarily a financial matter. She was very smart, very capable, and she went out and joined the workforce and did well there. My father, I think was always very frustrated by his decision not to complete college. Initially his choice of a career was engineering. He attended Iowa State. He came home after a couple of years during a vacation break, and found that his father had hired a young man to shucking corn on the family farm who had an engineering degree from Iowa State. This was during the Depression. He probably was working for ten cents an hour and my father said, “This is crazy. Why am I doing this when I can farm?” So, that’s why he made a career decision that, afterward, I think he always regretted. He had quite a bit of ability in mathematics and didn’t really get to use that talent.
So, my parents both had more challenges than my generation experienced…They experienced the War and the Depression. They had a much more difficult and disruptive life, I think, than we do today. Those of us from the baby-boom years, we had pretty uneventful lives, at least up to COVID-19. The previous generation went through a lot more. Of course, in common with a lot of other folks of that era, they became rather conservative about finances and things of this sort, very determined that their children would do better than they had done. It was a matter of really great importance to them that all of their children went to college and got a degree, so we had lots and lots of positive reinforcement as we were growing up.
We had the great fortune, because of my mother’s wisdom of not wanting to live in Iowa, of growing up in Santa Cruz, which was this lovely beach town in California many, many years ago. You cannot find a better place to grow up in. I immensely enjoyed that place.
How did your family get out to Santa Cruz?
Well, it’s again because after the marriage that they had these contacts, friends, and family in California. They didn’t want to live in Iowa, so my father took on this idea that he could run his farm remotely and then move and make my mother happy, and so that’s what they did. My mother’s sisters all wound up located in the same part of California, and so it worked out really, really well for them, and of course really well for the kids growing up there, my brother and my sister and me. So, we very much enjoyed that part of our lives, just growing up in beautiful weather and beaches and not a lot of commotion in town. It was just about ideal.
So, your father was really able to sustain the farm as a source of income living all the way in California?
Yeah. So, he would hire a tenant farmer to take care of the farm, and I think they had an arrangement where they would split the crops between the two. He provided the farm and the buildings and the equipment, and then the tenant would work hard and bring in the crops and so forth. So, they had good years and bad years, but in general it actually worked pretty well. Even after my father passed away, we kept the farm for a number of years, until it didn’t really make sense anymore.
But I was fairly involved in that because one of the strange jobs I had as a teenager was working for a bank, and I became very quick with the adding machine, and so when my father did his farm taxes, which were pretty specialized—you couldn’t get a professional to do that because no one in California would know how to do the Iowa taxes for a farm—I would help him. I learned a bit about the business that way.
We kept the farm after my father died, operating it for a number of years. Then we sold it to a neighboring farm. It’s kind of an interesting story…My grandfather originally purchased the farm from that family. Thus after 70 or 80 years, we returned the land back to the same family and exited the farming business.
Did your mother work outside of the house when you were growing up?
Not when I was growing up, but when we became teenagers, it was very important for her to go back to work. She had worked in various small businesses when she was young, and then I think when I was 13 or 14, she went back to work. She worked for the California Department of Employment, which really…It was a clerical job more or less, but she enjoyed getting outside of the house after many years of not doing that. Ours was kind of a traditional family, how things used to be with one bread winner and one person raising the kids. They were happy with that mode, and we certainly benefited from all the attention that we had growing up.
Wick, besides your innate mathematical abilities, when did you start to get interested in science specifically?
Oh, very, very early on. In fact, I can remember some great stories. My dad in particular took pleasure in teaching us practical mathematics, so I probably was six or seven years old when I knew about how one could square the corner of a building using the Pythagorean theorem. The importance of a 3-4-5 triangle my father would bring out.
I can remember him…This is something I did with my own kids because I enjoyed it so much when it happened to me. My father taught us how to measure the height of a tree from its shadow, and I remember repeating that experiment with my kids and being delighted with how clever they were in figuring out how to do the algebra associated with that. So, I liked that a lot.
My father was this very practical person who still understood basic mathematics and really thought it was terribly important, so we somehow got the idea while growing up that it’s good to be able to write well and all that sort of thing, but the math and the science are really quite special. So, I got that message very early on.
I also was very lucky. We had a neighbor who had a big influence on both my brother and me. Living immediately next to us was a retired fellow who had come from England. What was his name? I’ve lost it right now. It was so many years ago. He was the nephew of Bertrand Russell and had had a storied career as an engineer. When still quite young he was one of the principal engineers on the Trans-Siberian Railway and did all kinds of other interesting projects during his life.
He was interested in science and while there were a lot of kids in the neighborhood, few of them were interested in such thing. But he found out that my brother and I were the exceptions. He subscribed to a number of magazines: he’d bring Scientific American and Scientific Digest over to us every month so we could read them. We got really interested in Martin Gardner and things of this sort. Our neighbor would do experiments in his garage. I remember a Cartesian diver he constructed once. We were just fascinated by that, so he enjoyed the fact that there were two kids in the neighborhood that were interested in science, my brother and me, and took care of us.
I remember my mother was horrified once by one of my neighbor’s ideas. My parents left on vacation for 10 days during the summer, and the lawn usually required mowing every four or five days. My grandmother was taking care of us. Mikey (my brother) and I were talking “Gee, you know, the lawn looks pretty bad. We should try to cut it,” but my father, being a tough guy, had a push lawnmower and we could not push it through the lawn. So, we told our neighbor that we had a problem, and he said, “Well, I can fix that up for you.” [Laughing] So, he constructed a harness for us so that one of us could pull the mower while the other one pushed, and it worked marvelously well. We mowed the lawn that way. We were really proud of this.
So, when my parents arrived home, we excitedly told my mother, “We’re going to mow the lawn for you now,” to show her this harness. She looked out the window and saw what we were doing and she was horrified! [Laughs] What would the neighbors think of her treating her children this way?! So, she immediately ran out and told us, “Take off the harness and come inside quickly!” J.W. Bournier. That was our neighbor’s name. Mr. Bournier was really a fabulous guy. [Overlapping voices]
You went to public schools throughout?
[Yes.] Actually, you know, of mixed quality, but what I remember are a half a dozen fabulous teachers that had a huge influence on me while growing up. I never really thought about this deeply, but I think I benefited from exposure to an older generation of teachers. There were some very talented teachers who were just about to retire, where I had the opportunity to attend one of the last classes they ever taught. They were especially rigorous.
I remember that sophomore math in high school was geometry, and my teacher was in her very last year of teaching. She was obviously a very, very bright woman who probably went into teaching because it was a career that was open to women, when many others were not. She was very rigorous and liked challenging us. I remember we had to prove the Pythagorean theorem by a particular method that she chose, and she knew exactly that if you didn’t cut any corners, there had to be 102 steps. So that proof was one of our challenges. If you gave an answer that had 98 steps and not 102, she went through it until she found what little conceptual mistake you had made. So, she made a lasting impression on me…
Then I remember my senior year there was this fabulous fellow who…I think he was a wonderfully gifted pianist. He had been very close to his PhD in mathematics and something happened that prevented him from finishing. Mr. Greene gave us some magnificent problems. He would save special problems for the most talented students, which he would give out year to year, hoping that a few might actually solve them. So, we had lots of great challenges in the public school.
There was also a fabulous physics teacher, a very young guy. Somehow folks had noticed that I really liked science, and so I was put into physics as a junior, though physics was a senior class. Things were very regimented in those days. You carried a label that determined which section you would go into, and the strongest students were directed into a college preparatory system of courses. So, I took the physics course that year and did really well.
I remember him giving me some of his college textbooks to read on the outside because he thought I could do that. He was always frustrated that we didn’t know enough calculus yet, that our math training lagged. He taught us a kind of “backyard calculus” during the physics course. It took maybe a week to get through that, but it was enough for me to understand the basics of calculus and then to use it in physics, so we were really lucky. His name was Wayne Zeck, and I believe he continued as a teacher for many, many years, working in a private school somewhere in the Northwest for most of his career. He was a marvelous teacher.
He was also an experimentalist. He was married and working on his PhD part-time in geophysics when he taught us, but he would do experiments in the classroom that probably would not be allowed in any classroom today. [Laughter] I remember the one that was most scary. He put a kid inside of a big oil barrel and put the lid on top and then charged it on the outside to some high voltage, then de-charged it and opened it up and the kid was still alive. That was how we learned about Gauss’s law. [Laughter] Zeck was a marvelous teacher.
Then because I had nothing to do in my senior year, they put me back in his class and it was sort of a special studies in physics. I also took a course from him in geology when I was a freshman, and I think if the courses had been reversed, if he had taught me as a geology as a senior, I would have wound up being a geologist or a geophysicist.
He had that much influence on me. I also had a marvelous history teacher that I remember very much. He taught us US history by having us read and discuss the Federalist Papers. I mean, that was a very high level in those days, requiring really serious discussions about the basic concepts of the Constitution. So, I think a lot about that today, with all the issues and polarization in our politics. Perhaps we don’t really understand the civics foundation of the US. It seemed important to me to actually go through the debate that was associated with our original Constitution. So, I think I had a pretty darn good education all in all, despite the fact that it was a public school and there were courses that were not as memorable, mixed in with the ones that were very, very memorable.
It makes sense, given that you had a terrific institution right in your backyard in the form of UC Santa Cruz, but did you ever think about going farther away from home for undergraduate?
I did…not too far. [Chuckles] In fact, UC Santa Cruz was not there through most of my youth. I guess it was opened up when I was…My junior year in high school was the first year of UC Santa Cruz.
Oh, wow! Brand new!
Yeah, it was brand new. I did apply to several places as an undergraduate. There were two I was interested in. Again, I loved California, and both UC Santa Cruz and Berkeley were of interest to me. But in part, the decision was made…I had a girlfriend and she applied to a number of places, and the one place that we both got in was UC Santa Cruz.
That does it.
So, I went there, and again, it was a terrific choice, in part because there were no graduate students.
Meaning you got all of the professors’ attention.
Exactly! I guess when I was a junior, I wound up in research with Mike Nauenberg. I didn’t have any idea what I was doing, but Mike was…We were kind of scared of him. He seemed in the classroom to be particularly rigorous, but I greatly enjoyed working with him. I remember he gave me a problem that he thought I should be able to solve, an electrodynamics problem. I worked on it for a while, and it turned out I had solved it. I just didn’t realize that. The solution was one I wasn’t familiar with. It was a parametric solution, and so finally he insisted I show him what I had done. I gave him my work and he said, “That’s what I wanted. That’s the correct solution!” [Laughs] Then he told me, “I gave this to the mathematicians, and they couldn’t solve it.” [Laughs] So, I felt very, very good about that.
Mike was also another person who had a great deal of influence on me. Later on, when I went to graduate school, he would often come over to Stanford because of the connections with SLAC. I noticed that there were a couple of young people in the department, students, that he knew, and I always appreciated the fact that whenever he showed up -- he would be interacting with the senior people at Stanford—but if he saw one of us, he would come over and say hello and ask how we were doing and so forth. Also, he was very important in me pursuing a career in physics because I had--As an undergraduate at Santa Cruz, I took majors in both math and physics. In fact, I probably did more math because there was a better variety of advanced courses available, and some graduate courses were opening up then. So, I took a lot of those.
What about the astronomy program, Wick? Were you involved at all with astronomy?
Yeah. Astronomy became a major UCSC focus somewhat later. I didn’t really think too much about astronomy in those days, although it did turn out that when I went to graduate school, my initial choice of subfield was general relativity. As an undergraduate, I had worked with J.W.T. Youngs, a mathematician at Santa Cruz. He had solved, with Ringel, an important problem in mathematics, the generalization of the four-color map problem called the Heawood conjecture. He had reduced it to something called graph theory, and the require proof basically became kind of like a game, requiring one to impose certain patterns on distinct classes of graphs. It was a problem that was accessible to an undergraduate who worked really hard, and so I got involved with it. I was always good at patterns and so forth, so I was able to help them improve a couple of sections of their proof, finding alternative solutions to the ones that they had published.
In part because of him, I applied to graduate school in mathematics, and I was convinced that that’s what I should do. Youngs had a connection with Stanford, and he was particularly interested in me applying to Stanford and perhaps continuing to work with him and getting a very quick PhD. It turned out he passed away that spring from a sudden heart attack, very unexpectedly.
I can’t remember if it was Michael Nauenberg or others, but I remember a couple of the physics professors came by and talked to me about changing my graduate school plans from mathematics to physics. I recall them telling me “You do mathematics like a physicist.” [Laughs] “There are certain kinds of problems you can do well because of your physics,” and I realized, thinking about it, that they were absolutely right. They persuaded me that I should go to graduate school in physics.
I remember telling them that I was leaning toward going to Stanford in mathematics. I had not applied in physics nor supplied a GRE score in physics. One of them said to me, “Give us two weeks. We can fix that,” and sure enough, two weeks later I got an offer to attend graduate school in Physics at Stanford and it was a great choice. I was very grateful that my Santa Cruz professors looked after me and had a sense of what I was good at.
Relating it back to classroom work, I remember I got involved in a very strange course at UCSC that was taught by Robert Hermann, who was a well-known group theorist in mathematics, and very interested in mathematical physics. This course was a graduate course, a rather advanced one, a pro seminar, but there was a typo in the catalog that made it appear to be a sophomore course. So, I showed up at this course along with a lot of my sophomore friends, prepared to take it. It sounded very interesting, mathematical physics, linear algebra, things of this sort.
On the first day of class, he pointed out the catalog error. He started going down the rows and asking, “What have you had? What background?” “Professor Hermann, I’ve had linear algebra and calculus,” and he would say, “Well, you’re not qualified. You’re going to have to leave.”
So, one after another, all of my friends left. I was the very last guy in the very last chair. He was about to do the same thing to me. There were four graduate students left in the course at that point, and one of the graduates spoke up and said, “Professor Hermann, you need five students to make a course.” [Laughs] He asked me what I had, and I told him I had algebra and calculus and he says, “If you stay, I’ll guarantee you a B.” [Laughter]
So, I stayed in this course, and I loved it because it was all kinds of crazy things about deformation and rotations and so forth, and I could see physically what he was doing. He was very much a mathematician, so I remember he was just amazed that I knew that a top that was slightly deformed would wobble when it rotated. You know, that would be obvious to any physicist, and yet a mathematician might not have the same intuition. [Laughs]
So, I learned a lot in that course because I not only had a teacher, but I had four graduate students who all took an interest in me. When I was working on some of these very difficult problems, I could get help from any one of them, and the experience taught me a certain scientific toughness, that one can do things that are really, really difficult if you work hard and ask for advice and spend some time searching the literature and so forth. It was a very good experience. That’s what I got in Santa Cruz. Then I was really happy. Looking back, that was the course that should have given me a sign that I was a physicist, not a mathematician.
And particularly, Wick, given your mathematical abilities, when you were getting advice about graduate school, I wonder if the advice specifically was that you should focus on theory.
Well, there was no doubt that I was going to do that because I was not particularly a star in the laboratory [laughing], in contrast with my older brother, who also went to UC Santa Cruz and was two years ahead of me. He was quite talented in the laboratory, and I definitely did not have his talent in that area. I would be the guy that would take the longest to figure out how to turn on the oscilloscope, so not a good sign of future success as an experimentalist.
Wick, on the social side of things, being an undergraduate in the late ’60s and early ’70s, what was the campus scene like at UC Santa Cruz? Was there an active anti-war movement? Were you political at all?
There was. I would say I was sort of apolitical, although I certainly followed events. What I really liked, though, about that time was the new campus with kind of a new philosophy of teaching, cluster colleges, very intense core courses. So, I had the feeling of complete immersion. I would be in a certain course, not science or physics, and just feel like I was living in a different era thinking about ways of looking at society that are very different from what one would get in a normal course. I liked the very intense teaching structure of UCSC as well as the kind of community participation that came with the campus’s core courses.
Living in the dorm—da Vinci Dorm—I had a great bunch of friends who were all rather good scholars and students, so we would talk about what we learned and discuss and debate. The Vietnam War, of course, was a very big deal for us, and we spent a lot of time reading books to try to understand exactly why this war came about and what the solutions might be, so I really found that very, very good.
Then Cambodia came. That had a big effect on us because Santa Cruz basically shut down during that time. I was taking electrodynamics when the shutdown came. I don’t think I ever recovered. [Laughs] I always felt that that was…Whenever an electrodynamics problem comes up, I have to sit down and think a little bit harder, and I have a feeling that I never quite had the foundation I should have had because of Cambodia. But then there were--
Was the draft something that you had to deal with?
It was. That was the time of the lottery. I lucked out in getting some incredible number. Those people who got terrific numbers don’t remember them. I know mine was something like 320, but I don’t remember the exact number. If you got a poor number like 77, you remembered it because you’re probably going to be drafted.
So, I never had to worry about the draft because it never got that far up in the numbering system. I was lucky in that regard. But it certainly did…The political activism, and then of course coming to Berkeley much later in life, with all the history of the social movements at Berkeley, this is one reason I have such a liking for being in a public research university. It’s more connected to the people than a private university. It’s more responsible. I think we get a greater variety of students and backgrounds at Berkeley and at the University of Washington than many of our competitors, and I’ve always liked teaching in that environment where I know many first-generation students in my class are really, really interested in doing well, not only because they’re intrinsically interested in the subject, but because they view learning as a path forward economically for their extended families. I like the feeling that I can contribute to this upward mobility in society through places like the UW and Berkeley.
Did you apply anywhere else besides Stanford for graduate school?
I did. I applied to Berkeley, I applied to Rice, and I applied to MIT. I think I got into all of them. The offer at MIT wasn’t quite to my liking, so I eliminated them. Rice was a bit of a backup school, so it came down to Stanford and Berkeley, and Berkeley had a Regents’ fellowship that they offered. It was a really attractive offer, so I debated and debated about this. I’ve never known whether I made the right decision or not, but I decided to go ahead and give it a try at Stanford. I did not really have a reason—it was more of a coin flip. Stanford was an hour’s drive away from UC Santa Cruz. I accepted the offer without ever going over to check it out or anything.
[Laughs] It was a different time!
[Laughs] I know! I looked at the brochures and decided …
Was SLAC part of your consideration at all?
I’m sorry. Was what?
Was SLAC, joining SLAC sort of something that was part of your consideration or attractive to you?
I certainly knew about SLAC because that was a big component of the research that was growing at UC Santa Cruz. I don’t think it was a big, big deal. I was mostly interested at that time in astrophysics and general relativity, so I thought that would probably be what I would do in graduate school.
And to the extent you thought about possible professors to work with, who was doing GR at that time at Stanford?
Well, Leonard Schiff was there, who had some interest in this area as well as others, and he was the person I knew about. Again, today’s students are much more thorough than I was then about investigating what was actually available, but that was enough, one person I knew of was enough for me to conclude, “I should just go there.” I had this kind of naïve view that one can go wherever one wants and then it will all work out, and that turned out actually not to be the case at Stanford. In particular, Schiff passed away before I arrived at Stanford.
I think it was that summer just before.
So, he wasn’t there, but there was a lot of interest in the gravitational wave detector that was being built by Bill Fairbank, and Stanford was looking for a theoretician to support his group. They hired a young guy from Princeton, Remo Ruffini, and Remo taught this unusual course in astrophysics. I don’t think he had a syllabus or a very good feeling for the background level of his students. But he made the course exciting. I remember early in the course he said, “We will all write a paper this quarter,” and you know, that’s kind of a daunting homework assignment for students.
He described a series of possible research problems, in one case pointing out “I think this one’s easier,” and I decided it would be a good idea to pick the easy one. It turned out to be the only problem that was actually workable. It involved a code describing electromagnetism in the curved space around a black hole, and it wasn’t quite as advertised. It was clear after I got into the code that it was a work in progress, not yet ready for applications. There were a lot of little problems to sort out, and I learned enough about computing from a friend of mine at Stanford, a fellow graduate student, to sort through the problems, which helped me figure out the physics. In the end Remo and I wrote a paper about how particles spiraling into a black hole will radiate in their orbits. I enjoyed that and I felt I had gotten a pretty good start on a thesis at that point. Remo and I remain friends to this day.
Apparently, Remo may not have hit it off with others at Stanford, as he returned to Princeton at the end of the year. So, I found at the end of my sophomore year I didn’t really have a thesis plan or an advisor. Bob Wagner had just arrived, so there were opportunities to continue in astrophysics…But at that time Bob was working on problems about galaxy formation that didn’t really resonate with me.
So, after a bit I decided to try something different…The theory group leader was Dirk Walecka, who is a marvelous teacher, so I told Dirk that I was not going to continue in astrophysics and wanted to do something different like maybe nuclear theory because I knew that’s what Dirk did.
Yeah. What was Dirk working on at that point?
Well, at that point he was working on weak interactions, but he changed very soon afterward. He was just beginning to think about dense nuclear matter, particularly a field theory approach now known as the Walecka model, a tool for modeling nuclear matter at different densities.
So, you sensed what he was transitioning into and you thought that might fit well for your interests as well.
Well, he was just beginning work on the Walecka model, and I remember Siu Ah Chin and I were two students who were talking with him. We would meet, and Siu Ah was more advanced than me, having a better foundation in field theory than I had. It looked to me like this problem was going to be kind of a reach for me at that stage in my career, and it was also not the kind of astrophysics I hoped to do. It was a little bit more of a nuclear physics problem.
Wick, what does that mean? What kind of astrophysics did you want to do? What were you thinking about?
I kind of wanted something that would really relate to observation, and in principle you could argue that what he did would eventually connect to neutron star structure and so forth, but at the time it looked to me like it was more of an abstract nuclear physics problem focused on creating a field theory to describe nuclei and nuclear matter. That is, it is a very challenging problem. Dirk did have a huge influence on me, but because of the earlier work he did on semi-leptonic weak interactions— almost everything that goes on in astrophysics has some connection to weak interactions.
It turned out that getting a solid background in weak interactions is a fabulous way of getting into astrophysics as kind of a second field, and so that’s what happened. Dirk realized this. He didn’t want to take me on as a student because he already had four students at the time, and I know he would have been pleased had I worked with Bob Wagner, as Dirk was very interested in building up a strong astrophysics program at Stanford. Instead, he connected me with Bill Donnelly, who was an assistant professor relatively new to Stanford. Bill worked with Dirk on weak interactions, and then while I was there, also with Roberto Peccei on a number of related problems.
Where did Bill come from?
Bill originally grew up in Canada, and I—if my memory serves, arrived at Stanford from Toronto. Bill later left Stanford to spend most of his career at MIT.
But I was Bill’s very first student, and I think he and Dirk worked together to plan my thesis problem. Initially Bill asked me to do a lot of reading on semi-leptonic weak interactions, starting with Dirk’s review paper. One day I said, “Well, isn’t it time for us to start working on something?” and Bill then reached into his desk and pulled out the notes describing what I was supposed to work on. I think Bill was just kind of waiting for me to say it was time.
And I was very lucky. They knew they had something that would interest me because of an event during my first year at Stanford. There was an upcoming colloquium by John Bahcall on the solar neutrino problems. The graduate students had recognized that even colloquia could be hard to follow. Colloquium speakers often didn’t really lecture at the graduate student level. The graduate students thus would have a noontime meeting every week, in which we would prepare ourselves for the next colloquium and—one of the students would be assigned to provide the other students with some background material on the subject of the next colloquium, so we would be up to speed when the colloquium was delivered. Dirk was a mentor for this student group. I was assigned John Bahcall’s colloquium. In fact, I remember both Dirk and Bob Wagner were there when I gave the talk, and they helped correct what I got wrong. [Laughs]
…which was hugely influential. It was tremendously lucky for me that this subject was something I was going to love, and yet I was randomly selected to give this presentation. So, I learned as much as I could about solar neutrinos in a week and gave this talk. I remember particularly Bob had a lot of comments about things that I had kind of gotten wrong, but I had the basic idea and so I understood John’s talk when he presented it. I didn’t get to meet him during that visit, though, but did a couple of years later. When I asked Bill about my thesis, he pulled out notes, saying, “There’s a new neutrino beam at Los Alamos. It’s interesting. Can one do a calibration of the chlorine detector there?” So, I worked on that. That was half of my thesis, and I really enjoyed learning about the details of the experiment, and about the nuclear and weak interaction physics relevant to the detector…
Did you spend a lot of time in Los Alamos?
I did eventually…Again, that’s an interesting story. I went there as a post-doc later on. So, when I left Stanford…I finished in about four years: It seemed to me that Bill wanted to get me out as quickly as possible, and I was always amazed that he thought I had done enough. But now looking back, while it’s a decent thesis, I wonder why couldn’t I have done the work in a month instead of two years? [Laughter] You know, there’s a learning curve, and we professors should remember what it takes as a graduate student before one can actually do anything.
But the thesis was decent. I got a couple of nice papers out of it, and then I applied for jobs various places. I didn’t know where to apply. My friend, John Dubach, was doing the same thing. John was very organized and so he had a list of 100 places that we should write, so I wrote them all just like John did, and got some good offers back—one in Canada and one in Michigan. Then I had an offer from Dieter Drechsel at University of Mainz. The Max Planck Institute for Chemistry is there.
Dirk advised me not to go there. He thought that one of the other offers was probably better for me, but I was tired from the thesis effort, and it seemed kind of interesting to go to Europe. So, I took a chance of going there despite his advice…In those days, it was thought that taking a post-doc in Europe might reduce the chances of getting future jobs in the US. I didn’t find that was true. So, I moved to Mainz. Laura and I had a neat apartment there in a suburb right next to—we didn’t know it at the time we signed the lease—a US Army base.
I was a pretty good tennis player in those days, and they had public clay courts there where I lived. A lieutenant who served as player/coach of the Army tennis team saw me. He recruited me to the Army team, though as I had fairly long hair in those days, it was pretty clear I wasn’t legitimate. Everybody always looked at me suspiciously: a team of buzz-cut GIs that were playing tennis and this one guy with long hair. [Laughs]
But we had a marvelous time in Mainz because a lot of the German clubs with wonderful clay courts would invite the Army out for matches, and the Army would reciprocate by bringing its cooks. Army trucks would arrive with barbecues and beef flown in from the US, and the cooks would take care of us and our hosts. The matches were half social and half tennis, and I really enjoyed this opportunity in Mainz. And then my physics supervisor Dieter was a terrific mentor. The day I arrived he became dean…
…which in some sense is bad news, but it worked out for me because when I checked in with the administrator at the Institute for Nuclear Physics, she noted I didn’t speak any German. She said, “Well, I have a really nice office, but it has no phone in it, but that will work out well because nobody’s going to call, as you don’t know any German.” [Laughter] So, I said, “Fine!” and it was a nice office out in an area they called the barracks. It was otherwise occupied by a fellow who was described as the inventor of color TV, the German version of that, and he was doing some really interesting science involving video and biomechanics.
This big office had two desks, and Dieter discovered that since I had no phone, if he worked at the second desk in my office late in the afternoon, nobody was going to bother him. He did that often, working on his correspondence and stuff like that and we could talk physics, so it was really great.
My physics took a different turn, photo-pion physics. At the time there was a lot of experimental interest in photo-pion physics, and I did some nice calculations of pion production at the Bates (MIT) and Mainz electron facilities, I realized then that the intersection with experiment could be important to a theorist’s career, as the experimentalist really liked what I did. So, I remember going to a meeting where it seemed like every other speaker was showing my graphs. [Laughs] I said, “Well, this is a good idea. You find out what is going on experimentally and what’s relevant and you try to--”
And what were some of the big experiments that were going on that were relevant at that point?
It was basically the very early days of what we would now call chiral perturbation theory. There were ideas about how to construct the low-energy Lagrangian for pion production, and they were basically doing experiments to see if they understood the various multipoles that were contributing. There were some interesting issues. I remember reading a paper that Adler had done—it was actually part of his thesis—about how to handle all the terms in the expansion in powers of the pion mass.
So, it was a good work…not particularly profound, but useful and rewarding. I learned a lot by doing it. Basically, experimentalists wanted to know the implications of what they were measuring, and I was able to help. The calculations were kind of a messy combination of the nuclear physics of response functions and the pion production mechanism.
Also, I benefited very much at that time from the fact that my friend from graduate school, John Dubach, had also gone to Europe. He joined the Dutch facility Nikhef on a NATO fellowship, and it didn’t quite click for him. I had only been in Mainz for a short time when John called, saying “I’m actually thinking about leaving Amsterdam. I can take my fellowship anywhere in Europe.” We had worked together as graduate students, doing one paper. He said, “Why don’t I come down and work with you in Mainz?”
So, that’s what he did. He arrived with his fellowship, and we did work on electron scattering, exchange currents, and related issues. I enjoyed tremendously working with John. John taught me everything I know about computing, and I always felt my computational skills ceased developing when John left me [laughs] because my method of learning was, “Hey John, how do you do this?” He would then tell me. [Laughing]
Wick, what was your funding while you were in Germany? Were you on NSF funding?
No. It was done through the German government, the DFG. That was another interesting story. The first time Laura and I had come there we had Eurail passes because we wanted to take a nice European vacation at some point. We decided I should get a six-month start on my physics, and then at the very end we’ll take the vacation. The pass had to be used within six months.
It turned out that week corresponded to a meeting of the German Physical Society, and Dieter wanted me to give a talk on the work the DFG had so kindly funded. This looked like a problem with no solution. But Dieter was the Dean, it was still a time in Germany when university professors commanded great respect, and deans even more. The local train officials had told me “There’s nothing we can do. We can’t extend this due date,” But Dieter offered to make a call to the headquarters in Frankfurt. I was invited to headquarters—it turned out to their executive office—where someone with apparently great authority put his stemple on my Eurail pass extending it two more weeks. [Laughing] So, that’s how we got our vacation in Europe. We had a great time in France and Spain.
It was a really wonderful institute environment, not only Dieter but Arenhoevel was there. They had both worked in Europe and in the US. They had created in Mainz a very open American-style group, so it was a terrific environment for me. I always enjoyed it. I didn’t stay too terribly long because I was always a bit concerned about returning to the US, before too much time passed.
I started to apply for positions back in the US, and I was very fortunate to be doing this at the same time as John. I had known about Los Alamos and their new facility, LAMPF, which produced the neutrino beam discussed in my thesis. When I thought about where I’d like to go, Los Alamos was very, very high up on my list, and so I applied. The Lab advertised in Physics Today for postdocs, and I responded.
Then, somewhat to my disappointment, John got an offer from Los Alamos [laughs] and was invited to interview. About the same time, he also got an offer from MIT which he decided to take, before he arrived in Los Alamos. So, he told Los Alamos this while he was there—the theory group members in T-5. On returning to Mainz he told me that someone there had responded in roughly the following way: “That’s terrible because we needed somebody who does weak interactions because of LAMPF and you’re the only one we could find with the right skillset.” He responded, “Well, what about Wick?” and they responded, “Who?” It turned out my application had gone into some—it’s a huge laboratory—elsewhere, never getting to the theory division and T-5. With that hint, they found my CV and they agreed it was a really great match and I received a very nice offer.
Los Alamos, for me, really that was a career builder. I thrived in that environment. I had fabulous mentors there. Two young theoreticians, Peter Herczeg and Joe Ginocchio, were my official postdoc mentors, and in the years I was there, there was an extraordinary flow of nuclear and particle visitors to Los Alamos. We had what would be regarded today as a huge visitor budget for summer visitors, and it seemed like everyone in physics passed through at least once. Problems discussed with the senior researchers tended to filter down to us postdocs, so we would be presented with so many ideas for new projects. We postdocs would hear “Why don’t you work on this? Why don’t you work on that?” So, I got some great ideas.
That’s where I learned about double beta decay, for example. It had a big influence on my career as I was able to modernize both nuclear and particle physics aspects of the underlying theory. But the need for this work came from a T-Division advisor who was critical of existing work. The suggestion came to me that somebody ought to work on the formal development of the theory of double beta decay, and I decided that was a good idea.
I got ideas about parity violation and time reversal violation studies from Peter, Joe, and others. They were always fabulous in looking out for me, very smart, very modest theoreticians who were always putting me first in the work we did together. I never could write a paper with Peter because if I did my part, then Peter felt he didn’t do enough. [Laughs] And Joe and I actually did collaborate a little bit there, and then we had some great collaborations after I left Los Alamos.
When I arrived in Los Alamos, I was still unsure whether I wanted to stay in physics. I was actually thinking about doing something else, but within just a few months of being in that wonderful environment, I was completely convinced that I was a physicist, and I should stay with that career.
Wick, how well sheltered were you (or not) from the military, national security, weapons aspect of Los Alamos?
You know, I don’t know what all I should say here, but years later there was somebody that referred to the scientists as these crazy cowboys. [Laughter] I think it’s probably a little different today, but certainly in those days, the holdover from the war days of “This is a laboratory about science and scientific activity and openness” was very much on the forefront. So, there was a lot of weapons stuff that went on in the laboratory in other divisions, but the theory division was an amazing place, 200 theoreticians who operated in a university-like way. I don’t know if there was anything comparable to it in the world at that time.
Everything from biological physics to new ideas in nonlinear physics was emerging there, and then the standard core nuclear physics, astrophysics, and particle physics was excellent. Amazing breadth of research. You could learn anything you might need by finding the right person in T Division. Plus, the computing was terrific.
And then it turned out that John and I again intersected there later on, and we spent a lot of time using up all of the computing resources we could find. VAXes were a new thing and by that time John and I had worked together and kind of mutually decided that we needed to understand many-body theory and computation, so we kind of taught each other that. We rewrote a shell model code together…a reworking of the famous Glasgow code, which was in part in machine language. I always thought John and I complemented each other beautifully. He was much more the computer scientist, and I thought a lot about algorithms, and together we could do some really, really good work.
So, Los Alamos was perfect for me. It had the neutrinos, it had the computation, and it had the colleagues that I needed to really do well. They took care of me. When I finished my post-doc, I remember Joe and Peter came over and said, “We’d like to keep you. We’d like you to apply for an Oppenheimer Fellowship,” which were great fellowships, so next thing I knew, I had one. I was paid enormously well for a post-doc [laughs], and it gave one a certain stature in the laboratory. Then a year or two later, I got…It was very hard to find faculty jobs in those days, and so you always…If you got an offer, you should take it if you wanted to go into academia, and I did. So, I had an offer from Purdue University, and I went--
Was the option to stay on as a staff scientist at Los Alamos? Was that available to you?
Well, this is the story. While I was an Oppenheimer Fellow, I was allowed to do some usual things, like taking leaves of absence. I would just apply to the post-doc committee for permission. It was a standing committee responsible for us, and they always said yes to our requests. One of my friends on the committee told me years later whenever any post-doc asked to do anything unusual, they would decide it was probably okay because no doubt Wick did this. [Chuckles] I took a leave of absence from the Oppenheimer Fellowship in order to try out the faculty position at Purdue.
Purdue had a little bit of conflict at the time, different groups that were not getting along with one another. I did fine, but I began right away to have some worries about the climate in the department. I remember going back to Los Alamos at Christmas, to complete some research…Chuck Zemach was the head of the post-doc committee, and I came to his office and said, “I would like to extend my leave of absence one more year.” I wasn’t sure I wanted to cut my ties with Los Alamos. He looked at me and he said, “You know, you likely want that because you’ll probably want to come back.” [Laughter]
Before I could even respond, he stood up and walked into the next office, which was George Bell’s office, the T Division leader, and he said, “I think Wick wants a job here.” [Laughter] Bell looked like…He wasn’t prepared and I was standing right next to Chuck. Bell looks up and says, “Well, I have to have a week to think about that.” [Laughs] So, we left and a week or two later I received a letter from George stating that if I wanted to come back and finish my fellowship that the Lab would pretty much assure me of a staff member position afterward.
Purdue really wanted to keep me, and in fact, through a very complicated procedure, they offered to give me tenure immediately if I stayed. But I thought about research environment. It meant a lot to me, the broader environment that I had at Los Alamos, so I went back to Los Alamos.
This is not so much a comment on Purdue; you were spoiled, basically. This might have been your reaction no matter where you went.
Yeah. They were incredibly nice to me. I mean, there were these problems that I noticed in the department that made me think, “This is different from Los Alamos,” and the chair at the time was trying to do everything he could to fix things. It was just one of these unfortunate situations in which big groups didn’t see eye to eye about certain things and it became personal. This experience influenced my career because I always…When I look at a new place as a potential new home, I take note of how the groups interact with one another and so forth. It’s an important part of a really strong department that those interactions be supportive.
But in any case, despite being…West Lafayette was not the West Coast, and my wife was aware I had reservations about making the Midwest home. [Chuckles] She said, “Can you tell me why you would like to have tenure in a place you don’t like living?” [Laughter] I thought, “That’s a pretty good question,” you know? We actually enjoyed West Lafayette. So, perhaps she was being unfair. There were so many social events and so forth in that small town and we really did have a good time there.
I wonder if also, Wick, there was some ancestral connection that you felt from Iowa.
Yeah, a little bit. I kind of liked it. The Midwest to me was sort of pleasant and I liked the people and I got on with everybody in the department. It was just these other issues that were interfering with good planning that I think continued for a few years and then were finally straightened out by the chair and others. But I never regretted…It was a great decision to go back to Los Alamos.
I had mentors there in addition to Joe and Peter. One fellow who helped me was George Cowan. George at the time was, if I recall, the number two guy in the laboratory, the associate director. He had come to Los Alamos in the war days. He had been a graduate student at the University of Chicago working on the chemistry of plutonium, a really important skillset. So, they brought him to the laboratory, and he wound up starting both the Chemistry and Nuclear Chemistry Divisions there and staying for his entire career. Through him I got linked up with Tony Turkevich from the University of Chicago and Ray. We became really good friends because of our shared science interests. They were quasi-physics, quasi-chemistry experimentalists who worked together. George and I…
The first meeting with George was arranged—as I said, percolation from the top down. Leon Heller came to me and said, “There’s this fellow, George Cowan, who has an idea about proton decay, and he wants to talk to somebody, and I think it should be you.” [Laughs] So, I was told where to find George, and I remember it was really kind of embarrassing because, again, I still had fairly long hair in those days and I came to work in shorts and sandals and a t-shirt because you know, it’s the theory group.
Then I wound up in this new building which was the administration building up on the third or fourth floor. I walked into George’s office, and he had two secretaries, which I’d never seen before. [Laughs] One of them gets up immediately when I said who I was and she opens this door and George is in there with maybe half a dozen, ten people all with suits and ties and stuff. She whispered something in George’s ear and George stands up and says, “Gentlemen, I have an important meeting. You’ll have to leave now.” [Laughing] I said, “Oh, I wish I had at least put on shoes today, been a little bit more presentable,” but they all streamed out and then George told me about this idea of doing a geochemical experiment to measure proton decay. I went away and studied it and came back and said, “Well, it’s a great idea to isolate technetium in a deep underground ore, but the problem is there’s a background, solar neutrinos.”
So, the idea became a solar neutrino experiment which we actually did up in a mine in Colorado. It wasn’t quite successful, but it was still a very interesting experiment. Enormous quantities of ore were being extracted from the mine—10 kilotons a day—which they concentrated before shipping to a processing plant in Iowa where they smelted the ore. George rigged up this marvelous resin column that would intercept the gas flow, as he knew the technetium would be outgassed and collected the technetium and rhenium from the gas stream, and then did the assay.
I just loved working with George. He was such an interesting guy, and through him connecting with Tony and others…It spun me off into double beta decay experiments, and then interactions with Ken Lande…We work on experiments that could be done in the LAMPF neutrino beam, and so I got involved in this experimental-theoretical interface that I acquired a pretty deep way of thinking about the experiments. I remember Ken made me really happy one day when he said, “You’re about the only theoretician I know that actually understands experiment.” [Laughs] That was an exaggeration, but I did get a pretty good handle on the experimental details.
Then years later, a few years later I wound up…Frank Avignone and Frank Calaprice did an experiment on axions—again, with a connection to Ray Davis because they used a neutrino source that came from Davis. He wanted to use the source in the Homestake mine, but it turned out to be too heavy to get down the lift, and so the Franks borrowed it for this axion experiment instead. They completed the experiment, but they had a disagreement on how to do the data analysis, for which I had previously done the background theory. They wanted to know how do axions interact in matter, so I had worked out the theory they needed.
I waited and waited and there was no draft paper because they couldn’t come to agreement. I finally said, “Well, look. Give me the data and let me try—you know, a third opinion.” [Chuckles] They did that, so I made up…You know, I had never done data analysis before, so I just made up an analysis, folding it in with all the theory I had done. They both liked it and we published a paper.
The referee report was…I remember to this day. It said, “You know, this experiment’s okay, but the data analysis is fabulous!” [Laughs] So, I felt, in the end, that all of the interactions with these really terrific experimentalists had helped me broaden myself out, making me appreciate why theory is important because of its relevance to experiment. I always enjoy being able to help the experimentalists make a little bit of progress.
This is a theme that goes all the way back to graduate school. This was always important to you.
It is. Yeah. I think it was not so much a function of me but of the people I interacted with and the opportunities that came out. Physics is somewhat random; you never know what you could have done or should have done or would have done with some other path. At the various forks in the road, I took the paths where experiment was important.
We should orient ourselves back geographically and chronologically. What years are we talking about, and where are you affiliated now? Were you already at Washington?
No. I spent almost seven years at Los Alamos, arriving at the beginning of 1977 and leaving in ’83, late ’83, for the University of Washington. So, that was a long period which included the break at Purdue. It also included a break for a “sabbatical” research visit to Princeton, joining Frank Calaprice to learn about some of his weak interaction experiments. But in total, it was connected to Los Alamos for seven years.
Ernest Henley, who I worked with, was a frequent visitor to Los Alamos, and he was very interested in parity and time reversal, and so he and I started collaborating. He was also an advisor to T-Division, a member of a review committee. I don’t know if an advisor is supposed to do this, but I shared a moving van with another fellow from another T-Division area, when I departed for Seattle. Ernest convinced both of us to leave T-Division to come to University of Washington. [Chuckles]
The University of Washington had approached me at one point, I think a year before I decided to leave, about an offer. It wasn’t quite the right offer, and it came about in a strange way. The offer I did get that year was from Vancouver. I kept thinking about the West Coast, and I love Vancouver. TRIUMF was a new place that was very much like Los Alamos. I was very interested in this job, and I went there for an interview, and they made an offer. The salary was not very high, and it was expensive in Vancouver.
So, I thought “Gee…” It was not quite as vibrant a group as I had in Los Alamos. So, I came back from TRIUMF through Seattle and gave a seminar there, and I remember being in an office with Jerry Miller and he asked me, “Well, why are you out here on the West Coast?” I said, “Well, I had kind of a job interview up at TRIUMF,” and he said, “Oh, you’re interested and you’re movable!” [Laughs] There was kind of a glint in his eye, you know, and it was just a couple months later I got their first offer, which I did turn down. Then a year later they came back with a much better offer that I--
Was it an open offer, or they created one for you?
It was interesting that…DOE supported the really strong UW group. The second offer that they made was a partnership with the DOE where they would bring me in for a couple of years. DOE would help with part of the salary and then I would continue on. I had a faculty track from the start, but it was all guaranteed that if I did this in a certain way that I had a tenured position there at the UW, so it was a really great offer.
When I interviewed there, the formal process, they did have…They did a full search, looking at other candidates as well, but I remember when Laura and I came for the interview, things worked out particularly well. It was the middle of winter, which is usually rainy and cold in Seattle, but instead we enjoyed an amazing week of absolutely brilliant blue skies. Everything was crystal clear and not a drop of rain or anything during the whole time. She just loved it, so after that, anytime I was trying to negotiate on the phone and she was nearby, she would just be saying things in the background like, “Shut up. Just say yes.” [Laughs] So, we were very happy with that move.
You know, I missed Los Alamos. It was tough leaving there because I felt tremendous loyalty to them, but in a way, I’ve kept my contacts with Los Alamos over the years. Lots of friends still there and some of them are in a physics partnership with us right now, so--
What was your title when you left Los Alamos?
I was a staff member then, so they had promoted me after the end of my fellowship to a permanent position.
And this is the equivalent of a tenure-line position or an already-tenured position?
It would be the equivalent of already tenured, although technically there’s no tenure in a national lab. If something happens, they can fire you. They made a great counteroffer. The then-division director was even willing to give me some kind of a group leadership position, which was not so appealing to me. But we did miss Los Alamos. It’s a wonderful place to live, with skiing nearby. Laura could take the morning shift for skiing and I would take the afternoon shift, trading off caring for our two boys. [Chuckles] You can’t do that in very many places. Nevertheless, I had the feeling that I wanted to go to a university eventually and teach, and Washington, I thought about it. Where else would I want to be? It’s a great department, on the West Coast, not too far from my family down in California. It seemed great, so in the end it was not too hard of a decision to move.
Wick, was your sense that UW was in growth mode at that point, that it had a great group of physicists, but it was really looking to enter into the next tier of departments?
I think so. Clearly, Ernest Henley had a huge influence on my career. I always liked working with him as a theoretician, but he was a marvelous man in terms of how he knew how to interact with people and also because of his style of leadership. He was incredibly important to the UW. He was dean during some of the really, really difficult times they had, and he steered them on a very, very good path. I would just see him, how he reacted to difficult situations. I was never blessed with innate tact [chuckles], so I would just marvel at him. I would see him in situations that were socially awkward with four or five people, and there would be one person that instantly reacted in the right way, and it would always be Ernie. He had this ability just to know what to do to help other people, so having somebody like him as a mentor was incredibly important to me. It helped me…
We worked together on a proposal for the NSF that was the forerunner of the INT. We weren’t successful, but I learned a lot about writing proposals. Then a year or so later, there was an idea—it originated from Gerry Brown, but that the Department of Energy embraced it—to create a national center for nuclear theory. We decided that we would compete, so Ernie and I worked on that proposal pretty hard. I did most of the organizing and writing, but Ernie was always there to advise on all issues.
Wick, who were some of the other contenders institutionally?
Yeah, it was pretty clear that it was going to go to one of two places. There were five contenders. These were pretty big collaborations, so it kind of split up the nuclear physics community, but the strongest proposal was one that involved Brookhaven, Stony Brook and MIT. It looked like a real juggernaut. Then there was another very strong one out of Illinois with Illinois and Argonne, so we were kind of on our own. But we made some--
Yeah, seriously! I would not be betting on UW at this point.
Well, I had known the story about the KITP. [Laughs]
A friend of mine competed for that, and the final choice came down to Santa Barbara or Santa Cruz. This guy looked at me and said, “If you don’t have a beach, you’re not in the competition.” [Laughter] It struck me that Seattle is a really great place to visit all times of the year, and folks like the city with its amenities and so we had some advantages.
Then when we designed our version of the INT, we focused on creating a national institute that would serve the entire country. I think that the major contenders made the mistake of saying, “Well, we’re the strongest place in the country. We have all this talent. We’re going to advertise this talent, and it will be a privilege to come here.”
And we took this very other different viewpoint of focusing all of the resources on the community and trying to be good stewards. Instead of flaunting our Nobel Prize winners, of which we didn’t have any at that time [laughter], in our presentations we would feature the students and the education they were getting and things of this sort. Of course, that was very, very wise because, as the big universities and labs were competitors, the selection committee came from places that…Most of the faculty that were on that committee came from smaller places. So, what we said really resonated with them.
It was a shock to the DOE when the committee wound up…I guess there was one holdout to the very end, but in the end they all decided that they would be unanimous in picking Seattle as the site, and the DOE was not at all happy about that report. [Laughing] I won’t go into political details, but it went up to a very, very high level nationally whether or not this report sees the light of day. But in the end, the DOE decided that we were okay, that they would site it at Seattle. David Hendrie initially wasn’t happy with the decision, but to his great credit, two years later, I remember having a conversation with him during which he said, “You know, I wasn’t a supporter of you guys, but this is a great institute. I’m really happy with it.”
Wick, this idea that one of the things that your proposal stood out as that you would be stewards for the community and you would be outwardly looking in terms of the service that you would provide for the whole country—what does that mean in the world of nuclear theory? How can you be of service beyond the academic questions that are happening onsite?
Yeah. So, I think for us what that meant was two things. First of all, the DOE concept behind the INT was to prepare theory to help support the big facilities that we were then creating, RHIC and Jefferson Laboratory. That problem comes back to the fact that our community in nuclear physics, especially at that time, was very dispersed. Remember that experiment was always done, up until that time, in small tandems, so there were small experimental groups in lots of different universities, and they tended to have one or two theoreticians associated with them. So, you had this problem of a lot of good people in a lot of random places around the country. How do you get them organized to support a big facility?
So, that’s why we emphasized programs and workshops that would bring the community together, focus on a certain theme, get folks interacting, and then send them back out to their home institutions with the notion that those partnerships and collaborations would continue. What we proposed had that concept behind it. What we actually said in the proposal—I was amused a few years later to go back and read the original proposal and compare it to what we had done. We actually did much, much better. [Laughs] The idea was there, but the actual implementation required trial and error: we learned as we went along of what worked and what didn’t work.
What we wound up with was an institute that would bring in somewhere between 600 to 800 people a year for various workshops and other events. Especially at the beginning, we focused on these long, intensive three-month programs where folks really got deeply into collaborations while they were in Seattle. We took the viewpoint that we wanted to push back the boundaries of nuclear physics, that we saw a lot of the opportunities in areas like astrophysics, nonlinear physics, atomic physics, particle physics, and so we wanted to feature these intersection areas in the field. So, we put a great deal of effort into recruiting program organizers from these boundary areas.
I remember one of the things that really helped us in the very early years is that Norman Ramsey came for one of our workshops on electric dipole moments and time reversal. He had a great time, and he went back to the DOE at a very high level and said, “This is a fantastic institute.” I remember my old friend Mike Nauenberg came and he was very skeptical about nuclear physics, but he spent a week there and he said, “I would have told you before coming that this was a dead field, but this was terrific.”
So, I think we were successful…I mean, nuclear physics suffered from a PR problem. There was a lot of good physics going on in the field; there always was. But somehow, the breakup with particle physics had given the field this image that these were the folks who were left behind, when in fact they were just focused on a different set of problems but were doing really, really creative work. I think--
Wick, historically, where would you locate that, the breakup with particle physics? Roughly when did that transition happen?
I think it was probably the era when Dirk Walecka would have just been entering the field.
And when SLAC was created. I mean, there was certainly a…At Stanford you’d see the rift between the department and the national laboratory.
There was a feeling among many that if you weren’t doing high energy physics, you were no longer modern. We and condensed matter were in the same boat at the time. This was not some…Condensed matter had to deal with the “squalid state” view of that field, so…And to our credit, I don’t think we ever gave up. I do think that in my generation, there were a number of good people who took a little bit of the criticism to heart and tried to move out into different areas and push these intersection areas that brought vitality into the field. That was very, very important to us.
So, the formula at the INT was right for the entire field, recognizing there’s a lot of talent and a lot of interesting problems, but also a lot of opportunities in these boundary areas. So, if somebody measures an electric dipole moment in an atom, you’d better understand the atomic physics, the nuclear physics, and the particle physics, and the hardest parts of that are the many-body physics and we are necessary for that.
It’s a theme in much of my research throughout my career. I often take on problems…a recent one was dark matter scattering off nuclei…and really drill down to understand how to create the interface between the particle physics and the nuclear physics. How can you distill the nuclear physics in the simplest possible way, but in a theoretically rigorous way, to make the connection with the high energy guys who are worrying about the UV theories and integrating down to the nuclear level? How do you teach a particle theorist what you can and cannot learn from direct detection at very low energies? That’s a problem they have a hard time with, but we can help. So, I’ve always appreciated the importance of establishing this interface.
I’ve gotten a lot of support from my particle physics colleagues over the years that…You know, they still cheat in some ways. Some particle friends have argued that, you know, “We like what you do because you’re not a nuclear theorist,” and I’d say, “No, you don’t understand. I’m definitely a nuclear theorist. You like what I do because it’s relevant to what you do.” There’s a really important distinction there that I think was lost on the field for quite a number of years.
Wick, just to clarify the politics beyond this and also the science, so what you’re saying is there was no specific breakthrough in nuclear theory that fostered interest in the creation of the INT. The science had always been there; it was more of a gradual PR understanding that there needed to be more heft behind the field. It wasn’t that it was a backwater and then something happened that made it exciting. That was not really the issue, you’re saying.
Yeah. But I would say it’s not quite so clear. I think that it was a backwater in the sense that we were not sufficiently reaching out to these other fields and [overlapping voices]—
But again, that’s a PR issue; that’s not a science issue.
Well, I’ll give you an example. When I came to the UW, I was really interested in neutrinos, and I can remember the first review we had from the DOE. I won’t name the program officer, but he was a big figure. He walked in the door and the first thing he said was—he hadn’t even said hello to anybody—“I don’t want to hear the word ‘neutrino’ today.” [Laughs] So, they were sending messages that nuclear physics had these boundaries around it. I was one of the people that fought this idea. If we could see that the exciting physics was neutrino physics, then that’s what we should do—and I was working on double beta decay and the solar neutrino problem, and one couldn’t find better problems than those.
Today the DOE today views double beta decay as one of the most important things we will do experimentally for the next ten years. [Laughs] So, they’ve come around and they now appreciate neutrino physics. SNO was a fabulous success, and we played a big role in that. I think that project’s success made an impression. We’ve actually influenced how things are done, and the stove-piping in the DOE has diminished, and they’re much more open to new things. I find today that you don’t have to fight these battles quite so hard because they’re open to this notion that nuclear physics at the intersection areas can be very, very rich and vital. Of course, in a way, even at our major facilities like RHIC, we are studying problems that are relevant to high energy physics: jet physics, the equation state of QCD in regimes that connect to some of the issues of interest in astrophysics. There’s a general awareness in the field that nuclear physics is a much broader, much more diverse field than it would have been defined as 30 years ago, and I think that’s—
Did you work with Hamish Robertson at all when you got to UW?
Yeah. I had a pretty big influence on the department in terms of recruiting. There was an effort at CENPA, which is the nuclear physics laboratory, a wonderful place, to hire, and they were initially planning to hire in a more traditional area to support their tandem physics. My co-conspirator at Seattle and an enormously good friend, Eric Adelberger, and I got together and concluded, “This is not the right direction.” The first effort that they made to hire in that area failed. This gave us an opportunity, and we argued “There’s this fabulous group at Los Alamos that does this neutrino physics. We should just bring them here to Seattle.”
The recruitment was quite a battle. The group was not anxious to move. We had to figure out all kinds of reasons that they should move, how they would be able to do their physics better at the UW. When Hamish, John Wilkerson, and Peter Doe came to Seattle, it had huge impact. It changed CENPA’s direction, and now of course it’s continuing with people like David Hertzog joining the effort, bringing new physics like the muon magnetic moment. So, I feel Eric and I had a positive influence on that department by broadening and strengthening its nuclear physics. I think in some ways…
We hired folks like David Kaplan and Dam Son in the INT. I remember when we were considering David—we had a search committee—walking into a committee meeting while thinking, “I really like this guy David Kaplan, but everybody else is going to think it’s a reach.” [Chuckles] But in fact everybody had come to the same conclusion: this guy was just fabulous. So, we hired him (and Ann Nelson!) and DOE supported us. Then we hired Dam Son. Half my friends said, “You must be crazy!” and the other half said, “That’s a brilliant move!” Of course, the brilliant move turned out to be absolutely the right description. We hired people who were in the mode of the INT, folks who would break down barriers and do new things, and it paid off for us tremendously well. And we helped influence the rest of the department through department hires like Hamish and John.
Now were you the inaugural director of INT?
Kind of. When it was first decided, we wanted to get an outside director, and so there was an interim period where Ernie Henley was the director. Our top two choices were Steve Koonin and John Negele, and we made—particularly with John because we thought we had a good shot with him—really strong efforts to hire them. I have always wondered whether John, then or later in his career probably, ever regretted not taking the director’s job. That would have been an interesting alternative career path for him. He did, of course, fabulously well at MIT.
We had an outside committee running the search and they called me in one day and said, “Since we can’t get these two great guys, you’re next in line.” [Laughing] They offered the job to me. I had some rough edges then because I was pretty…I was so interested in spreading the field that I was known as a little bit of a partisan, you know. Neutrinos versus the rest of the field. [Laughs] So, they said, “You’ve got to learn how to take the rough edges off and support everyone,” and that was great advice.
I took that advice seriously…I thought of myself as kind of like “Now you’re a parent and your children are everyone in the community and you want to make everyone better.” It was a really good way of thinking about the job as director—and I had Ernie who always instinctively supported others. Every time I had a problem, I could go in and talk with Ernest, and if I told him about something, he’d either come back with a really good suggestion or he would say something like, “I’m sorry you feel that way.” [Chuckles] That was his signal to me that I was completely wrong, and I’d better go back and rethink my position. He didn’t want to tell me I was wrong, but he would let me know in that way that I should rethink things. So, I learned a lot about how to help the community and be positive about my interest in broadening the field, while at the same time doing things in a very constructive way that helped the core of the field as well. I think we got it just about right at the INT.
Wick, what was the strategy in terms of co-locating faculty? Did everybody have joint appointments in the physics department as well, or how did you work that out?
Yeah. We were kind of lucky. We argued for something that the University had not done before and they agreed to it, which was to make us fully-tenured faculty members, but treat us as if we were on permanent leave from the department. We had few people in the UW administration who were willing to create new policy for us. Especially the Vice-Provost for Research, Alvin Kwiram, who did so much for the INT.
Meaning no teaching responsibilities? Did not have to take on graduate students, that kind of thing?
We were expected to take on graduate students, but technically we were paid by the DOE and therefore we were responsible to the DOE. The INT members were protected in the sense that they had tenured positions. If the INT ever collapsed, they would just move back to the department with their tenure. INT faculty were department members in every way except for teaching. Then, of course, we all missed teaching and so we volunteered to teach, but as our teaching was voluntary, we had choice in what we would volunteer to teach. So, we tended to teach courses where we could find graduate students, which worked out really well for us. The INT director serves at the pleasure of the DOE, so the DOE can replace the director at any time. In practice, the DOE was incredibly supportive, working as a partner.
So, it was a good system. INT Fellows were in the unique position of being tenured members of the department without teaching obligations. As director, I worked pretty hard, but it was the most pleasant possible work because two-thirds of my job was just talking to the visitors. Everybody wants to talk to the director, and I enjoyed it as well. These interactions would take a lot of my time and affected my physics productivity, but I would learn physics from all these wonderful people who would visit and find out what they were doing and what they were about and so forth. So, I really felt in those days that I was completely attached to the field, with a unique perspective on what was going on across all the different areas.
Wick, kind of a macroscopic perspective question from your vantage point in Seattle. The early years for the DOE, of course, saw the cancellation of the SSC. Did that affect your world at all? Did that affect the way that DOE might have put more resources into INT than it otherwise would have? What were your feelings on that?
Yeah, I don’t know if that had any direct financial implications for the INT because DOE is divided into offices that operate independently. But I do think that it certainly changed the course of high energy physics and probably helped the INT in the sense that it was easier to interact with high energy physics because of our focus on topics like neutrino physics and low-energy tests of symmetries. Those were areas that were very rich in particle physics as well. At the UW, the SSC cancellation primarily impacted our experimental high-energy group. We had just built a new building, occupying it in 1995. It had been designed in part with the SSC in mind, with high bay areas that would allow us to do equipment development for big experiments, so it was sad when the cancellation happened. We were going to be one of the participants in the SSC. But it’s also a good lesson. I remember one of my high energy friends telling me what he thought the SSC would actually cost [laughs]. We got that pretty wrong and paid the price.
Yeah. Yeah, yeah.
So, mistakes of that sort have consequences.
Who were the key people that you may have dealt with directly in DOE?
David Hendrie was really important at the beginning—
Where was he? Office of Science?
He was head of the Nuclear Physics Office. We had kind of a rocky start because he really very much wanted the INT to be at Brookhaven to support RHIC, but again, it didn’t take him long to recognize we were doing a really good job and he became quite supportive. As director one is always interacting with the DOE in kind of an adversarial way—“We need more money”—and they’re reluctant to ramp you up quite as fast as you’d like. But I have no complaints about Dave. He was a real supporter of the INT. And then it went on…Dennis Kovar took over from Dave Hendrie, led the Office for a long time, and he did a marvelous job. He was always on our side at the INT, always doing his best to help us out.
To go back to this theme about your appreciation and comfort in both the world of experimentation and theory, as director how did that inform your mandate or the way you wanted to see the INT unfold?
We made an effort in every program to have the experimentalists come as well. They were generally willing, and not only willing but they often found it kind of a delightful experience. The few who joined were the belles of the ball. Two or three experimentalists in a group of 20 theorists get a lot of attention, and the experimentalists enjoyed that. Our experimental colleagues have always been incredibly supportive of the INT.
In fact, that’s one of the great strengths of nuclear physics in general. I’ve been in many DOE and NSF meetings, and the experimentalists in this field really do support the theorists. They understand why theory is important, why it’s relevant. We’re often easy to forget because we’re a small part of the budget, but if they’re pressed with “Should we find some way of helping out theory,” experimentalists in our field are inclined to say yes. They really do appreciate what we do. That helps us, adds to the stability of nuclear theory. In contrast to particle physics, where parts of that field have gotten so abstract that making connections with the experimentalists is difficult, we have always enjoyed a partnership.
I can remember once being invited to give a seminar for a prestigious experimental group in high energy physics as part of their normal series. [Chuckling] “We invited you because we thought we might be able to understand you.” [Laughs] It helps a field to be grounded in phenomenology, and that aspect of nuclear theory has worked out really well for us. In an area like the solar neutrino problem, we were right in a sweet spot. We knew enough to critically look at solar models and the error analysis that goes into that, drawing the right conclusion—there’s something really interesting going on here that we should invest time in.
Wick, what opportunities did you see at INT to engage nuclear astrophysics, nuclear astrophysicists into the overall framework of INT?
Well, you know, neutrinos were really a focus, a key component of nuclear astrophysics in those days. One project that we launched—and I wish I had done this better—was DUSEL, the NSF program to create a national Deep Underground Science and Engineering Laboratory. Hamish and I had come to the conclusion that we needed something like Gran Sasso or Kamioka in the US to keep up, and so we called a meeting to engage the community in this discussion. We had some ideas going into that meeting about where we would wind up.
But things turned out differently because literally a week before the meeting was to start, Ken Lande called up with the news “Homestake announced that it’s going to close.” He was still working at Homestake, involved with the program Ray Davis had developed. Homestake mine was the legacy property of the Homestake Corporation, and they were soon to go out of business, merging with a larger company Barrick. The Corporation was interested in preserving its history. The mine had played a major role in the development of mining technology in the US, so they liked the idea of maybe science moving in and continuing the history.
So, with Ken’s announcement, we thought, “Gee, we ought to really consider this. This is not the way we wanted to build an underground laboratory with a big old mine like that that has to be pared down and with vertical access and lifts that date to pre-World War II, but we can get in there quickly and we get very, very deep. Maybe it’s worth considering.”
John Bahcall and I had become very good friends by that time, and offline we discussed how to proceed. As the INT was the sponsor of the meeting we held, John urged me to simply appoint a committee to move forward, and I did so with John chosen as committee chair—very incestuous. [Laughs] Kevin Lesko was asked to be cochair. It was a committee of wonderful people, among the very best in underground science in the US, theorists and experimentalists. We asked them the question of “What should we build? We have Homestake. We have other options. We have a great proposal for a horizontal-access facility at San Jacinto, from the UC Irvine group. What should we do?”
The committee did a great job, concluding, “If you can get Homestake quickly, if you can get it with a lot of infrastructure transferred, even though it’s not exactly ideal, we should do it. Its depth is what we need. But if we can’t get it intact and quickly, we ought to do something different like San Jacinto.” So, that was the view of the committee John and Kevin Lesko led. They produced a report, which had no standing other than as a report the INT, but it certainly had legs and led to an effort by the NSF to create DUSEL.
After the mine was flooded, what became of the project?
Oh, it was really sad, you know. We ran into a political buzz saw in South Dakota. The best parts of the interaction with South Dakota—and I spent a lot of time there—involved the folks in Lead. I mean, they were so supportive of our proposal and so excited about it, even though they initially knew little about big science. In contrast, there was a certain amount of suspicion at high levels in the state government that these scientists were up to no good. “We have some asset, and they want it, and it probably isn’t in our best interest to turn it over.” It didn’t really make any sense to us, but that’s what we were dealing with.
We had terrific support from the senior senator from South Dakota, Tom Daschle. In fact, he came to the meeting that set us on the course to DUSEL-Homestake. I believe we held that meeting in Santa Barbara. Daschle supported the proposal and though he could get it done for us in a proper way, bringing in the EPA, doing inspections, conducting open meetings, eventually setting the stage for federal ownership and indemnity for the previous owners. He spent a year, maybe a year and a half, working on the legislation with two of the lawyers in his office, with the goal of getting this done for us.
Unfortunately, DUSEL wound up in the middle of politics. Daschle was a very prominent Democrat, the state was heavily Republican, and the creation of a new laboratory on the timescale we envisioned would have helped Daschle’s re-election. If he had brought home this fabulous project in western South Dakota, which is strongly Republican, it would have been a huge plus for him. So that was part of the reason we couldn’t get it done.
The window closed on the Homestake DUSEL proposal, when the transfer to Barrick came. Barrick didn’t have the same motivations as Homestake did to preserve that mine, and I think they saw a lot of liability in giving us access to that mine. So, that’s why the flooding came, and it was done in a way that was irreversible. They made sure—
What science was lost as a result of the flood, do you think?
We wanted to have a US laboratory that would compete in depth with the Chinese laboratory Jinping or SNOLab. We wanted it to be very deep. We weren’t thinking so much of the long baseline program, but instead about the very deep, very clean experiments that would have to be done there over the next several decades. So, the prospect of establishing a laboratory at 7,400 feet, which was possible there, was exciting—even deeper than SNOLAB, almost equivalent to today’s Jinping. We could have had a world-class facility for the smaller experiments, and those smaller experiments were very compatible with the facility’s attributes and so forth.
We did a terrific job on what we called the conceptual design report. We had some excellent help on the sly from some first-rate engineers from the Homestake Corporation that had retired but were willing to help…They wanted to see this done. We had a couple professionals from outside helping us as well. So, in the end, we understood it was going to be a very expensive project and we were truthful with the NSF about that. I think there was a…I think NSF never really quite caught up with us during that period. They had this viewpoint that they had a budget. It was $500 million and that would cover the science and it would cover the laboratory, and we were pretty darn clear that it wouldn’t. In fact, we spent an extra two months on the project after the flooding just because we wanted to get everything we had learned down on paper and provide it to them. We did that.
While all of this was unwinding, there was a change in the South Dakota governor. Governor Janklow to Governor Rounds while we were still working on this project. One regret I have is that our interactions with Bill Janklow had been so impossible that things had become acrimonious. We did not regard him as a stable partner, and I think he regarded us as carpetbaggers…Maybe it wasn’t entirely his fault, some of the advice he was getting was very antagonistic toward us. I think with Rounds, we might have actually had a chance, but by the time Rounds came in, it was so late in the game that I and others were ticked off. There was too much history, and even the locals had divided into factions. But I regret not giving him more of a chance. When Rounds took office, could we have started all over, preserving Homestake as a 7,400-foot mine? I do not know, but perhaps we should have tried harder.
Today I have my worries because I think for the long baseline program, the 1300-kilometer distance is not ideal. Nor did we consider a really big, big cavern in that rock as the ideal use. The rock is very competent, but it’s also somewhat brittle, so it gets to be tricky to build a large self-sustaining cavern. So, I suspect that the cost for a such a cavern will be considerable. Hopefully really good geo engineers are working on this. It can work. We did design a very large cavern for a big detector, but Homestake’s sweet spot was really the small, very, very deep experiments. That’s why we were excited about it originally.
Wick, another sort of existential question regarding the cancellation of the SSC. I asked before about budget, but it’s often been said that when the SSC was canceled, then the United States necessarily ceded leadership in high energy physics to Europe. Neutrino physics was sort of put on a pedestal that this was an area where the United States would retain leadership, and that’s still said today. I wonder if you can reflect on where you saw yourself in part of those trends, and if you saw it in those sort of nationalist kind of terms.
Not really, but I do think in a way we were always a little bit late in our responses to some of the physics trends. We’re not good at anticipating where things are going. You know, while we did a tremendous amount of good neutrino physics at relatively low cost, we could have done more, and we could have done it much earlier. And it’s not that we weren’t trying. John and I worked very hard on the gallium experiment. Los Alamos tried to help us out with people like Peter Rosen supporting us, but we never could quite get the program done the way it should have been done. We developed both gallium experiments but could not get the broader community to push hard enough for us. Seven years went by before the Europeans and Russians took over.
In the early days, with the chlorine result in hand, we really knew we had to do the gallium experiment. Both versions of that experiment were developed in the US. There were two high-level committees appointed to review the project. Both gave us sterling recommendations to go ahead. The experiment was not that expensive. We could have done the gallium experiment in those days for something on the order of $30 million, a first-class experiment. So, it’s a relatively small number, even then, on the high energy physics scale.
I think the community just wasn’t open to it. It was kind of viewed that…It wasn’t like it is today. The community had accelerator money and nuclear physics money and gallium was neither one. It wasn’t an accelerator project, so if one appealed to a mixed committee in high energy physics, they’re likely to tell you, “Why should we spend our money on that?” [Laughs] And nuclear physics wasn’t sure neutrinos belonged to that field…This helps to explain the “I don’t want to hear neutrino mentioned today” comment I recounted earlier. [Chuckles] Solar neutrinos were not considered part of either field, either…This situation continued for a very long time…I think it was Jay Keyworth as Presidential Science Advisor who finally said that “These neutrinos belong to nuclear physics. These neutrinos belong to high energy.” [Laughing] He had to make a political decision at some point to assign responsibility, and that’s actually how we eventually moved forward. But we lost a lot of time.
We tried for seven years to get the gallium experiment launched in the US. One of the letters I have in my archive that I will keep forever came from Till Kirsten, who was one of the collaborators of Ray. He wrote me afterward and said, “This is the primary argument I have for the decline of American science.” Till managed to launch GALLEX in Europe in one year.
He said, “I spent seven years working with Ray Davis”—Ray Davis!—“trying to get a modest experiment done that was terribly important, and the US wouldn’t do it. I go to Europe, and I get three countries to sign off and procure gallium in less than a year. That shows you how far the US has fallen behind.” I think there’s a lot of merit in what he said. We had a huge issue at that time about the failure…the stovepiping in the fields that prevented us from recognizing that there are opportunity areas that we should be working together on. I think it could have been so much better in neutrino physics for the US if we had jumped ahead at that point and done a gallium experiment. It could have accelerated the discovery by a number of years and really, really helped us out. In the end, of course, Japan did fabulously well. [Laughing] Canada did well, but we were a little bit late and that allowed others to lead.
Wick, between your excellent experience at Los Alamos and being at a DOE-funded facility in Washington, what opportunities did you see as director of INT to collaborate more broadly across the spectrum of national laboratories?
Yeah. You know, I think there has been more and more collaboration. A lot of projects have grown up organically between the laboratories. I think nuclear physics deserves a great deal of credit for building LAMPF at Los Alamos. That’s not a natural place to put a basic-science accelerator facility, but it was a terrific success, and it started us on a path that led to JLab, RHIC, and FRIB. We got a lot of support from a DOE NNSA laboratory for that facility because they could see the connections to their programs. So, I’ve always been very grateful to the DOE, in a sense, for their breadth of vision in understand that science is science, and whether it comes from NNSA or from the Office of Science, that there’s a mutual benefit in facilities like LAMPF.
Then we moved ahead. I think it was very, very good for us. We kind of got the message in a sense from high energy that part of the problem in our field wasn’t just that we were narrow and weren’t building in these intersections, but we were also not thinking about the intersections in terms of collider physics and so forth. So, the fact that we finally got on board and started building facilities like RHIC and Jefferson Lab and now FRIB—facilities that can support a lot of university groups— was an approach we learned from high energy physics, and it’s helped us a great deal. Today at LHC, there is a heavy ion program and also a particle physics program, with a certain flow back and forth. I think all that is terrifically healthy.
So, a lot of progress has been made, in an evolutionary way. The hard boundary that previously existed between nuclear physics and particle physics served no one. There were areas like low-energy neutrino physics that were caught in the middle of that split, and we paid a heavy price in terms of scientific impact by not addressing such issues early. But the situation is now better.
An administrative question. The national laboratory system I think is currently comprised of 16 or 17 national laboratories. Is there any particular designation that would make INT definitely part of that or definitely not part of that?
The INT has a DOE label. I believe the term is Center of Excellence. This is a designation they have used for several facilities around the country below the scale of national laboratories. They may not have the scale of a national users facility, but DOE recognizes they are special. So, you really…DOE has been consistently supportive of the INT, and you can see the results. Right now, with Larry McLerran as the director, it’s just still a beautifully run, really innovative place. A pleasure to visit. I go there whenever I have a chance.
To go back to that question about how well sheltered you were at Los Alamos from the national security stuff, is INT involved at all on the military/national security side of things within DOE?
Not at all. In fact, in the early days we had many international visitors during an interesting time (the breakup of the Soviet Union). We had all kinds of folks coming through. We were visited by some fairly spooky folks who were suggesting that we should provide them with a tally of the visitors and so forth, and we took the viewpoint that we don’t do that.
So, they just went away and didn’t ask us again about this. The openness of the INT has always been considered sacred, openness not only to a variety of fields within the US, but also internationally. We were the model and inspiration, I think, for the ECT, which is the European equivalent of the INT—a somewhat different model, but a similar visitor institute that has proven a great success. Ben Mottelson was very much involved in its creation, and with its location in Trento, Italy, it has served Europe really well in the same way that INT has served the US. And the interactions between the two institutes have been helpful.
So, this is to say that problems like the Wen Ho Lee incident and the subsequent creation of the NNSA—this was outside of your world for the most part.
Yeah. I think it had…Certainly, I had some friends who were at Los Alamos at the wrong time and who suffered a bit for this because of enhanced security concerns. It is unfortunate that that happened, but they sorted it out relatively quickly. What impressed me is that Los Alamos, when I was there, had a reputation of being a fabulous place for post-docs, and it has maintained its reputation for mentoring young people, many of whom wind up in universities afterward. The national labs, especially the NNSA labs, face a challenge because a generation of workers are retiring right now and need to replaced. Places like Los Alamos and Livermore are very aware that their partnerships with the university community are hugely advantageous, not just for the science, but because of the contacts that they make with young people.
We have a lattice QCD group that I helped get started at LBL that partners with Livermore and a couple of other places. Many of the young people who come to do lattice QCD remain, using their high-performance computing expertise on more programmatic problems. I know that also happens in experimental nuclear physics. So, they’re in the recruiting game as well as in the national security game, and the two go together. I think it’s a great formula in an NNSA laboratory: a strong basic science component supporting the programmatic side, with recognition that the two are mutually beneficial. The science component is a doorway to the rest of the world that benefits the entire laboratory.
Wick, what opportunities did you see as director of INT to serve in a mentor capacity either to undergraduates, graduates, post-docs, or even junior scholars?
Yeah, I think we did some good things there. I got very…I had a visit from Bob Eisenstein when he was the NSF Mathematical and Physical Sciences Director. It was the early days of the NSF REU program, and he showed me a map of REU sites with none in the northwest quadrant of the US. He said, “Wouldn’t you like to start one for us? We think this is a great program,” so I got involved in that. It was enormously fun to create a program. We would get 300 applications each year—unbelievably talented undergraduates.
The first four undergraduates that I mentored under that program—I typically did one a year in those days because I had the time then—continued onto to PhDs and strong research careers. One was Andrew Cumming, now one of the foremost experts on neutron star structure, working at McGill University. Marcus Brüggen became a professor at Hamburg, where he heads the high energy astrophysics group. Natalia Toro, who was awarded a New Horizons Prize, is at SLAC. Neil Weiner, New York University, is a world expert on dark matter. Those were my first four undergraduates in this program! [Chuckling] And most wound up doing something that was pretty close to the undergraduate projects I gave them, so I just…The REU program attracted incredible talent, making it hard to go wrong. It pleased me that work the students did as undergraduates wasn’t entirely disconnected from what they chose to do later on in their lives. This program is still strong at the UW. Deep Gupta is the current director of the REU program, which has continued to do well for 25 years.
We also got very involved in the National Summer School. The National Summer School was started by folks connected with Oregon State University, and earlier Texas A&M. One year something happened, and the school collapsed, as it lacked a base in the broader community. They couldn’t recover.
Steve Koonin used to have occasional meetings at a retreat that Caltech owned, and he would invite his close friends in nuclear theory. I remember sitting around with this group and hearing, “We must do something about this. The school must be stabilized. There has to be somebody behind the school to make sure it happens…backstops it every year.” I realized it was a great role for the INT, so the INT became the steward of the National Summer School in Nuclear Physics, and that’s been a huge success. It continues today. Almost every aspiring young nuclear theorist (or experimentalist) attends either as an advanced graduate student or as early career post-doc. So, I’m really proud of such steps to provide needed mentorship.
I had some great graduate students at the UW, as well. Calvin Johnson was my very first student. He was terrific. I always felt bad about Calvin because I had no way of calibrating him, so I had no idea how good he was [laughing]. Many years later when I realized, “Boy, was I hard on that fellow!” because he was so good. Michael Ramsey-Musolf was this really interesting young guy who Princeton “farmed out” to Barry Holstein and me. His thesis was amazing. The first version was 700 pages long, reflecting the volume of work he did.
It was just absolutely brilliant. Weak interactions, radiative corrections work. I had Tom Luu, who was another amazing student…Earlier I had worked with Mariana, who later married Tom. They were a couple, but I didn’t know it at the time. Mariana wanted to do condensed matter and I kind of was dabbling in this area, so we worked on one problem together. I think she realized that I was not the best advisor for that area. She got a better offer from Boris Spivak and gave me the bad news on a Friday. “Wick, I really enjoyed this, but I’m going to move over into a condensed matter theory group now because Boris has offered me a position.” I said, “Great.” Monday morning Tom comes in and says, “I understand you have an opening.” [Laughs] So, that worked out really well for me. Tom was one of my very best students—with a marvelous ability to both do theory and computation, and to put them together in wonderful ways.
I’ve never been able to work with a lot of graduate students, but I’ve enjoyed my one-on-one or one-on-two interactions with graduate students a lot, and it has continued at Berkeley. I’ve got a couple of excellent graduate students right now that are getting their legs under them, and it’s such fun to see the transition from learning to independence and productivity. They just suddenly know exactly what to do. That’s a great experience. So yeah, I’ve loved it all.
The INT has done well because it sponsors visitor programs that reach out into the community and help all of us. But its post-doctoral program has also been a great success. I mean, we once counted up how many of our post-docs went on to permanent jobs in universities and national laboratories, and it was well above 70%, an incredible batting average. All of these efforts build up the people infrastructure that we need for our field.
Wick, you experienced something of an interregnum between 2006 when you stepped down as director and when you went emeritus from UW in 2009. What did you do during those three years?
I went back to research. During that period, I began to realize that I was in danger of continuing to do the same things [laughs] that I had done earlier. No, being INT director is a great administrative job because I could continue to do research at a reasonable level throughout. It wasn’t like being department chair, which is all-consuming, and thus I didn’t have any trouble getting back into research.
Primarily, the decision to leave UW after that period was just that I felt there was a danger of being stuck in a rut, that if I were ever going to make a change and take advantage of the last 10 to 15 years of my career, it was the time to make the move…A move would force me to form new collaborations, new interactions, and to think about new problems. I just sort of intuitively knew it would be good for me to make a change. Indeed, I always had some regret about turning down Berkeley in 1990, because of the variety that would have come from that move (and because Berkeley is close to where I grew up).
In fact, when I actually made the move, my mother and my sister were both ill and living in Santa Cruz, and I thought, “Gee, being closer to them during this period could be really helpful.” So, that started my thoughts. It wasn’t…In the end, neither one of them survived long enough for me to make the move to join them, but it got things started for me.
Then when I visited Berkeley, again, the aspect of the department that just overwhelmed me was the friendly welcome I received from its various groups. I felt like each one of them wanted to welcome me to the department. Then I started meeting the folks that run Berkeley, and they were all scientists. The administrators were not administrators; they were scientists volunteering as administrators following Berkeley’s philosophy of faculty governance. Any university that has Bob Birgeneau as chancellor and Frances Hellman as a dean will value research. It was just amazing, the feeling I got that this is…I never thought I’d find a place as good as the UW, but I was convinced from my Berkeley visit that a move would be great for me, and it’s worked out that way.
Berkeley has been so supportive, both at the laboratory and on campus, you know, doing everything they could possibly do to help me succeed. The lab helped me start up the astrophysics effort that led to the hiring of Dan Kasen, who is quickly becoming a superstar in that field. It helped me start up a lattice QCD effort…The idea we ran with is still very fascinating—making lattice QCD talk to effective theory in a way that’s compatible with how we actually model nuclei. So, we created a program called CalLat. André Walker-Loud came to us as a postdoc, then returned to the LBL staff. Connections with the Japanese lattice community led to a partnership with RIKEN, Japan’s national laboratory, that now extends to areas like explosive astrophysics and quantum information.
In the department, I have links to both particle theory and astrophysics. I returned recently to dabbling in condensed matter, and my condensed matter colleagues took an interest. They saw a paper I wrote, invited me to give the 290 Seminar, and later persuaded one of their students to give me a hand. [Laughs] He told me “They say that you need to know more about the literature.” This student became a coauthor on the next paper. Berkeley faculty look out for one another and cheer each other on. I know other universities where groups are jealous of each other. Berkeley has a very different sociology. And it’s so fun—
Now the appointment from the beginning, was it dual appointment that you would be co-located at the lab and the physics department?
Yeah, and this furthered a long-term goal of the laboratory. The Nuclear Science Division had tried for many years to bring somebody in that would reestablish the connections with campus. LBL has a Physics Division, the home of particle physics and a Nuclear Science Division, the home of nuclear physics. The Physics Division has always been connected with the physics department on campus. The Nuclear Science Division, because of Seaborg and other great nuclear chemists, was initially partnered with the campus’s chemistry department. But over the years, nuclear chemistry declined in importance in chemistry, and so the connection between the Nuclear Science Division and campus atrophied.
Over the years many LBL advisory committees urged the NSD to reestablish a campus connection, with reasons including the need for access to students by NSD. I believe they twice tried to recruit Steve Koonin. Never could quite make it work…and they tried me and it didn’t work the first time. But this little window of opportunity showed up and they were eager to jump on it. James Symons, who was the associate director at the laboratory, very much engineered my appointment, but it had the strong support of campus as well and it’s worked out really, really well.
Did you take students with you from UW?
I took one, and it was a tough transition for him, but he did finish his PhD. It can be a challenge for a graduate student to move in the middle of a thesis, to leave a familiar place and have to get reoriented at another. But Berkeley did everything they could to help. They made him a Berkeley student and he completed a strong PhD thesis. He later took a postdoctoral position with Michael Ramsey-Musolf. The transition to Berkeley was probably easier for me than for my student.
Wick, over the years, when would you find yourself spending more time at the lab and when would you find yourself spending more time in the department?
You know, it varied. Certainly, my time at the laboratory diminished tremendously the last three years, when I served as physics chair. The lab was very, very generous in releasing me to help campus. They continued their support of me, but I’m sure they knew they would not get their fair share of my attention while I was chair. [Chuckles] I will tell you the chair job is a really hard one.
In a big department like that, being chair is equivalent to running a small company. The department is pretty darn lean, given its activities and responsibilities. We’ve had a wonderful staff, wonderful faculty, but there is just so much going on at one time. So, I pretty much was working seven days a week, 12 hours a day just doing chair things. I find it kind of exciting in some ways. When I came on board, we were in a lot of trouble financially. We had too few FTEs and so forth. I do thrive on challenges like this that require strategy and some degree of vision. I greatly appreciated how much support I got from the department and from the dean and other campus leaders. They responded to our initiatives, and I think we made some terrific hires in the past few years and got…You know, they came through with creative recruitment packages that allowed us to get some really, really talented people.
So, I’m pretty happy with the impact I had, but when COVID-19 hit, it felt like my 12-hour days were now multiplied by 1.5 or 2. It became impossible. I was very lucky to have a friend and colleague, Jonathan Wurtele, as the vice chair. He did just an unbelievable job dealing with space adaptation and on-line teaching—putting everything on his own shoulders because I could not keep up. His help allowed me to survive the last six months of my term. At one time I had told our dean, Frances Hellman, that I would continue for two more years, but I realized it was just impossible. It was quickly wearing out.
At the same time, toward the end of my third year, we were successful in creating a new NSF Physics Frontier Center at Berkeley, N3AS. I am the director, and I feel N3AS is an opportunity similar to what I had with the INT. I remember how hard we had to work to get the INT started, so I should (and want) to focus on N3AS. Frances was very nice to allow me to back out of my chair agreement at that point. I’m excited about the opportunity to develop this nuclear astrophysics center and its connections with the rest of the department, and with twelve external partners. At Berkeley it will help us knit together astrophysics, particle physics, and nuclear physics in new ways to support the department broadly. So, it’s a better use of my time, and in terms of scope, more reasonable for me than trying to continue as chair.
[Laughs] As chair, Wick, did you see any opportunity to improve—not that there was any problem necessarily, but any opportunities to improve collaboration between the department and the laboratory?
Yeah. I think it’s always been pretty positive, but certainly the lab helped me tremendously with our recent recruitment and retention efforts. They’ve been a strong partner, and very frequently we share a vision of coming physics opportunities. During my term as chair, we worked together to strengthen campus and LBL in areas liked collider experiments, condensed matter experiment, and quantum information. All of our peer departments are in private universities with deep pockets. Berkeley is the only public university among the top ten physics departments, and our partnership with LBL is one of the reasons we compete so well. As we have fabulous people, we also have many retention battles to fight, and the laboratory has consistently helped us. They also often partner on new hires. Their LDRD program is a source of funding for young faculty with LBL connections. But benefits flow in both directions. Our department helped LBL conclude several recruitments successfully this past year, and several of our faculty are in leadership positions at LBL.
So, it could not be better, and we’re really blessed to have a national laboratory on our doorstep with such a record of Nobel prizes and big-science leadership. LBL is often called the crown jewel of the national laboratory system. Being right next door to UC Berkeley and its fabulous students is not a bad deal for LBL, either. It’s a marriage made in heaven, and we’ve been lucky that folks like Mike Witherell and Horst Simon who run the laboratory recognize this, and work to keep our partnership really strong.
Wick, just to bring the narrative up to the present, when you recovered from being chair, COVID was still happening. What have you been doing in recent months? What’s been on your agenda?
Yes, I’ve gone back to doing some work, getting my students on track…reconnecting with my students to make sure that they finish with strong theses. And then I’ve been spending a lot of time organizing the new Physics Frontier Center. We just did our first batch of hiring for that. Of course, everybody is working virtually now, but we hope actual people will be arriving this coming fall. We had a previous program, also supported by the NSF, that resembled a mini-Physics Frontier Center. This project morphed into the Frontier Center. Thus I’m closing out one project while starting up a second, trying to engineer a smooth transition between the two. So, I’m excited about that challenge. I’ve got some great collaborators around the country: George Fuller at UC San Diego, Sanjay Reddy at the INT, Gail McLaughlin at NCSU, and Baha Balentekin at Wisconsin. Really, really terrific people who are part of the PFC executive board.
So, we have the task now of putting together this project with generous NSF support. It’s basically about multi-messenger astrophysics, which with gravitational wave astrophysics at a threshold, is going to be a huge deal. If one looks at the resources that are going into the astrophysics instrumentation to extend the fidelity and depth of our probes of the universe, it’s staggering. It’s many billions of dollars of new investment, and a lot of the physics underneath involves nuclear, neutrino, or atomic physics, the stuff we do. The theory wasn’t responding adequately to the growth of experiment and observation. Perhaps the PFC can do for these fields (nuclear astrophysics, neutrino astrophysics, dense matter physics) what the INT did for nuclear theory in support of RHIC and JLab. The NSF and its referees really resonated with our arguments and were willing to support us through the Physics Frontier Center program. A lot of credit goes to some terrific program officers at NSF, who were not hard to persuade because they were aware of the needs. NSF has long had a vision for this field, as one can see from its early and consistent support of gravitational wave astrophysics.
Competing for a Physics Frontier Center is not something one does lightly. It’s a year-long effort of coordinating a team and developing a science case. So, I’m excited. The PFC effort has been a good use of my experience in the field and my talent for organization. I still get more enjoyment sitting at my desk and working on my personal research. But while the PFC is a big effort, it still leaves some time for my research and for interacting with my students and postdocs, so I’m in a nice situation at the moment.
Wick, I’m not familiar with the term multi-messenger. What does that mean?
It means that now…A great example was the discovery of the neutron star merger a few years ago by LIGO. They detected the gravitational wave signature of the merger, which if you distilled down to basic physics, probes the structure and deformation of the stars as they merge, ultimately reflecting properties of the exotic dense matter at their cores. After they merge they produce an accretion disk and later a radioactively powered explosion known as a kilonova. The physics is multi-messenger because we have many different probes of a single event—gravitational waves, a variety of optical and other electromagnetic observations, a short duration gammas ray burst, and forensic evidence of nucleosynthesis. Dan Kasen, my colleague, with Elliott and Metzger worked out the theory of the kilonova to explain the radiation signatures that we would see: the optical observations, the gamma ray burst, the gravitational waves, the nucleosynthesis. These are the messengers. Multiple observations now constrain the underlying theory, testing whether we really understand what happens when two neutron stars merge.
There is so much physics going on in a merger—the multiple signals from one event—that the interpretation of the data is beyond the capacity of any one person. Our Center represents a collaboration of some of the best people expert in the various areas, who are committed to work together in order to make progress. Frequent interactions lead to progress. Our group is involved in the modeling of these events—the use of high-performance computing to simulate the events, thereby connecting observables with the theories that describe the underlying microphysics. Connecting the dots in this way should lead to progress, so that’s the idea behind N3AS. I think it’s a great idea. The problems are hard, but I think we got the right collaboration and right organization.
Central to our plans is the training of young people, including giving them unusual opportunity to build scientific breadth, as that is so necessary for success in this kind of field. We do not want to train postdocs as specialists because they’ll never recognize what the important problems are or who they should collaborate with, as the field is broad and interconnected. Thus, we started by forming a national collaboration that includes many of the field’s leaders, and we created a post-doctoral program that allows young researchers the freedom to interact with anyone in our network. Our postdocs do not belong to the individual sites, and they have the resources they need to travel throughout the network to collaborate in person (though COVID now restricts interactions to Zoom). They are free to seek mentors and advisors anywhere within this collaboration. I think we’ve so far succeeded marvelously with this training model.
Prior to COVID-19, I noticed that when a half a dozen of our young people showed up at a meeting, they would link up. [Chuckles] They recognize themselves as a group as opposed to individual members from Northwestern, Kentucky, UCSD, etc. They interact every week, and that builds community. It’s great to see. So, the PFC is built on an emerging science theme of multi-messenger astrophysics and a plan to train postdocs to be broad scientists, and we’ll see in five years how successful we are in making an impact on the science.
Wick, in what ways is this collaboration offering research that might make a big impact on some of the most intractable problems in cosmology?
Yeah. It can. We’re interested in dark matter, for example, because the explosive astrophysics we study provides environments that are far beyond the capacity of any laboratory to reproduce. One can explore the possible signatures of dark matter in such settings, then check to see if there is any observational evidence of such signatures. Many of our interests are cosmological, for example, the neutrinos in the early universe and the possible consequences new “sterile” flavors or new interactions. We may learn within the next five or ten years what the absolute mass of a neutrino is from its influence on large-scale structure formation. We may learn more about sterile neutrinos, or at least place limits on their existence, from their impact on nucleosynthesis in the Big Bang. We might detect dark matter through its interactions within a supernova or a neutron star, for example altering how a neutron star cools. They might be produced directly through interactions with or within these objects. One has to work through the various possibilities to determine whether interesting opportunities exist.
In the case of gravitational waves, we will be flooded with data in ten years. Every day should produce new events. In the case of neutron star mergers, much of the physics has to do with properties of QCD at four or five times nuclear density. What’s the structure of the center of these stars and how does that connect to what we have learned in the laboratory? We’re the ideal group to make this connection due to our familiarity with QCD, and we intend to learn enough about gravitational wave analyses to be confident that we’re handling the data properly. We hope to connect astrophysical tests at very high densities to our laboratory experiment at lower densities, clarifying the phase diagram of QCD. If we fail to do this, we may find ourselves with a catalog of neutron star merger events ten years hence, with little idea of what it all means.
We’re hoping to help them learn what it all means.
Well, Wick, now that we’ve worked our way up to the present, for the last part of our talk I’d like to ask one broadly retrospective question, and then we’ll look to the future.
So, obviously a hallmark of your career is that you’ve refused to be bound within one particular subfield. You’ve been involved in so many different kinds of physics. You’ve worked in so many different collaborations. Overall, what’s the connecting thread for you? What’s the thing that says, “Even though I’ve worked in this area and this area and this area, here’s my interest or my scientific viewpoint,” or even an intellectual tradition that you feel a part of that might connect all of these disparate areas of research for you?
Okay, I have to admit that I’ve never planned anything. [Laughter] I probably don’t have any driving philosophy. I’ve just always been curious about different problems.
But there are always choices, right, Wick, about what to work on and what not to work on.
Yeah. I think it all goes back to Los Alamos, where so many different problems were offered to me. I began to learn that by stretching a bit, one can learn more and then later one can do more. It’s a good strategy for developing. It may seem like at the beginning that tackling new problems is costing too much time. One will not generate the same number of publications as somebody else who decides to redo his thesis in six different ways, producing quick publications. Nevertheless, one begins to see connections and opportunities for new work.
For example, at Los Alamos I wandered into a collaboration with Kevin Schmidt, a many-body theorist who used Monte Carlo methods, who was interested in the fractional quantum Hall effect, and saw advantages in solving this problem not in a plane, but on the surface of a sphere. It turned out that Haldane had already introduced this idea. But once this mapping is made, interesting connections with group theory techniques used in nuclear physics emerge. The many-body states of interest have total angular momentum zero. So, that makes one curious whether one can contribute something that others have missed, because one views the problem in a different light.
I’ve always been lucky, fortunate, and grateful that my primary sponsor, the Department of Energy, has been willing to let me explore. Our field is not at all narrow. I mean, it has core interests but there are no strict boundaries today. As I mentioned earlier, this has not always been the case…If one is at the core a nuclear physicist, but pursue an unconventional topic that arises, it’s okay with them—if the quality of the work is high. [Chuckles] If one has a long track record with the DOE, there is a level of trust that the work will prove to have some relevance.
I remember a time at the INT—a bad year as too many tasks were coming across my desk. I was unhappy with my own research progress. My DOE program officer called about the INT budget. Then we turned to my own contract. I said, “You know, I’m really embarrassed about how little I did this last year,” and he says, “Oh, don’t worry, Wick. We know you’ve been busy!” [Laughs]
The DOE has always taken this long view. Researchers have ups and downs, obligations to the community, and so on. It takes away from the physics. DOE seems to have faith that we researchers are making good decisions, and they tend to grade us on our long-term record.
I have had less experience with the NSF, but I suspect they have a similar philosophy. NSF’s willingness to support our multi-messenger astrophysics has provided us with a great opportunity. The investment is significant, and they are willing to invest for five years with the expectation we will be successful, It’s a great strength of American science that it’s not programmatic. They trust that we researchers will exercise good judgement. There is latitude in what we decide to do.
Wick, we can take that--
But I’ve always been interested, though, in research that creates bridges. I find it terribly amusing when something ones know in one context proves relevant someplace else. That’s when I feel like I’ve made some progress.
Well, we can take that question right into the future for my last question. Of course, there remains no plan for you. There remains no understanding of what you might work on next, but if you can just…Using the power of extrapolation in terms of all the exciting work to do, in terms of all of the generous support that you and your colleagues enjoy from the federal government, what are the physics that are most personally compelling to you with time being a precious resource, and as a mentor to the next generation, the up-and-coming physicists, what are some of the things that you’re most excited about as they look forward to the many decades that they have in their careers?
Again, I think there are these sweet spots in physics, very interesting areas for young people to work in. We’ve already talked about multi-messenger astrophysics. Arguably, the four or five greatest discoveries in physics, at least in the particle-nuclear-astro side of physics, in recent years have come from this area. It started with neutrino masses, but then came dark energy and dark matter. The next generation of CMB studies is going to be fabulous. We now have seen Einstein’s gravitational waves and we have characterized the black hole at the center of our galaxy—amazing. Not only are these topics fun, but when you’re in an airplane and sitting next to somebody who sells insurance, you can explain what you’re doing and excite the listener. [Chuckles] I have colleagues who work in lattice QCD, and they have a much harder time explaining what they do. Path integrals do not work as an airplane topic. [Laughter] So, I’ve always loved astrophysics for its accessibility.
Another area I love—and I think it comes from Los Alamos; that’s where it really started for me—is low-energy tests of symmetries. As the scale of physics gets higher and higher, it becomes more costly to build new accelerators, and small increments in energy may leave a lot unexplored. The alternative “small science” of seeking subtle symmetry violation at low energy becomes more attractive. Such tests can probe energy scales beyond any current accelerator. The latest problem I’m working on with one of my students is motivated by the Mu2e conversion program that Fermilab has launched. It’s a small effort compared to their main neutrino program. The physics is part atomic, part nuclear, and part particle physics. How can we help particle theorists focused on UV theories make use of a new measurement? What aspects of UV theories can one constrain? We asked similar questions about dark matter direct detection recently.
I like problems that provide an opportunity to create an efficient formalism that others will find useful, that clarifies, and bridges between fields like nuclear physics and particle physics. There are great problems at the intersections of fields. I like working with young people who are interested in particle physics and astrophysics problems, but who also understand many-body theory. Then, when estimates are made, they are not off by orders of magnitude. So, I think people like me play an important role in that we look at problems in the way a particle or astrophysicist would, but we have the many-body expertise needed to deal with atoms, nuclei, or the bulk matter and plasmas found in astrophysics. So, I’m going to continue to work in this mode. I’m looking forward to retirement when I will have more time to do so.
Yeah, that’s right! Physicists never retire. That’s when the real work gets done.
I know, especially at LBL. They carry you out with your boots on. [Laughter]
Wick, I want to thank you for spending this time with me. It’s been a lot of fun listening to all of your perspective and insights, and I’m so glad we connected initially a year ago and that we’re still in this and we finally circled back, and I was able to do this with you. So, thank you so much.
Great. I enjoyed it tremendously. Thanks so much.