Mark Wise

David Zierler:

This is David Zierler, oral historian for the American Institute of Physics. It is February 18th, 2021. I'm so happy to be here with Professor Mark B. Wise. Mark, it's great to see you. Thank you for joining me.

Mark Wise:

You're welcome, and it's nice to meet you in the Zoom sense.

Zierler:

All right. So to start, would you tell me please your title and institutional affiliation?

Wise:

I am the John A. McCone Professor of High-Energy Physics, kind of a mouthful, at the California Institute of Technology.

Zierler:

And what's the connection to McCone, is there any particular connection with your work?

Wise:

There is some connection. John A. McCone was Chairman of the Atomic Energy Commission, which I believe funded research in High Energy Physics. McCone was an interesting fellow. He, of course, donated the money to Caltech for the chair, and he was, amongst other things, director of the CIA for a while. I think he resigned over issues related to the Vietnam War. He was cofounder of the Bechtel-McCone corporation which might have been the source of his wealth. The chair I hold that carries McCone’s name is very generous. It not only funds part of my salary but has additional funds for postdoctoral support. I am very grateful for the support it gives to my research.

Zierler:

Mark, a question that's sort of in the moment before we go back and develop your personal narrative and your family background. As a theoretical physicist, in what ways has the pandemic and the mandates of social isolation perhaps allowed you the bandwidth or the time to work on problems you otherwise might not have, and conversely, in what ways has the lack of physical interpersonal connection been a challenge for you over the past several months?

Wise:

So I think, for your first question, given the way I do physics, it really has limited my ability to think about more out-of-the-box things. For one thing, I have a son and daughter-in-law that live a block away. We end up watching one of their two children half the day, and it's pretty tough to do the creative things while you're getting interrupted frequently, although it's great to have him here. Also things just seem to take a lot longer, like preparing my Zoom lectures. It's the way I work, that makes things take longer, I'm more distracted, and a lot of my creativity comes from interactions, which are very few these days. So I'd say not a lot of upside, the COVID world is more of a downside for my research.

Zierler:

Yeah.

Wise:

But it's not forever, hopefully.

Zierler:

Hopefully. Well, Mark, let's take it all the way back to the beginning. Let's go back to Montreal and let's start with your parents. Tell me a little bit about them and where they're from.

Wise:

My mother grew up in Toronto, and my father in Montreal. I don't know how they met. Maybe he was visiting on business. I don't remember whether the wedding was in Montreal or Toronto, although I am sure my mother told me at some point. Back then, I believe the family would've taken the train between the two cities to gather for something like that. For the first four years of my life I grew up in Montreal. Neither of my parents had a college education. Actually, I'm sure for my mom that is the case but not 100 percent sure with my dad.

Zierler:

What was your father's profession?

Wise:

I believe he was involved in the making of suits. His father had a factory. To be honest I don't remember much of Montreal. My father left when I was four, and then we moved to Toronto. Our family never heard from him again. I have almost no memory of my time in Montreal, perhaps it was because his leaving was a traumatic event for me. But I still went back to see family there, mostly in the summertime.

Zierler:

Did your mom remarry, or did you have another father figure in your life?

Wise:

No, my mother never remarried. She was pregnant with my younger brother when my father left. I can't imagine how hard it was for her under those circumstances.

Zierler:

Mark, when did you first realize that you had special talents in math and science? Was it early on?

Wise:

Oh, no. In fact, I failed one term of math in grade nine. I was a rather poor student. In Canada when I was in school there were 13 grades. There's only 12 now. Kindergarten to grade 6 was one school, and then 7, 8, and 9 was another. It was called junior high then. I guess the analog here is middle school. I was a terrible student. I wasn't failing overall, but certainly was not a good student. And, in fact, my mother told me that in grade 9 the guidance counselor recommended to her that I don't go to high school, that I pursue a trade or something of that ilk. I don't think I have a tremendous amount of natural ability in the sciences. We grew up poor because of the circumstances I mentioned to you. In grade 9, I realized I have to do something with my life. And I went through the things I thought I might do. I was really terrible at sports, although I liked to play with my friends. In those days there wasn't little league. You'd go to the park with your friends and the two best players would choose amongst the others to make up the two teams. I would usually be picked, second last because one of my close friends was the captain of one of the teams and he didn't want me to be last. [laugh].

Zierler:

[laugh]

Wise:

So I knew that athletics out of the question. I didn't have great social skills, pretty minimal actually, so I was never going to be in business, or at least I didn't think so. Finally I said to myself, ok, let me read about science, let me try that. Maybe I can be a doctor or a dentist if I can get good at that. To start, I read books by Isaac Asimov and I found I really liked it. When I got to high school, there were some very good teachers and I got engaged more and just got better and better by working hard at it.

Zierler:

Was it physics that you were most interested in even in high school?

Wise:

I really liked physics in high school, but I also liked chemistry, so it is hard to say. And at the beginning I couldn't have imagined being a scientist but as I said, I slowly got better and better. I took a really advanced chemistry at my high school. I remember the name of the teacher, Mr. Ward. He gave a spectacular class. And then, when I got to college, I found it really easy because my prep was so good.

Zierler:

Uh-huh.

Wise:

Physics I found difficult but if I worked hard I could do well at it. I liked the challenge, so I went more in that direction. I had excellent physics teachers, as well. Ms. Falona was a very inspirational teacher for me. I like to mention their names because I don't think they get enough credit.

Zierler:

That's right, they don't.

Wise:

They change people's lives, in the lower grades, too. And you rarely hear them mentioned.

Zierler:

Mark, who were some of the professors in the physics department at Toronto who may have exerted a formative intellectual influence on you?

Wise:

Lynn Trainor who was a quite well-known nuclear theorist. I believe he was one of the first to work out some of the isospin selection rules in nuclear physics. He came back to Canada from the United States, because there were aspects of US society that he found not to his liking. He was my mentor early on. From the age of 15, I worked in the mornings before school, 6:00 to 8:00, and continued to so in my freshman year. I also worked full time during the summers. Professor Trainor, who was writing a book, let me help him with that project. He paid me during the summers for that and made me a co-author. I was quite close to him. Really a lovely man, he was very generous with his time. The other mentor was Nathan Isgur, who I did some of my best research with much later, after I became a professor at Caltech. Nathan came to Canada because of the Vietnam War. Unlike Lynn Trainor, he was American, grew up in Texas. But he also found that time in the US difficult, and so he left. I don't think he was at risk of having to go to Vietnam, it was more of a moral issue for him. Like Lynn, he was a really nice person who was very generous with his time.

Zierler:

Mm-hmm.

Wise:

Nathan played a huge role in my development as a physicist. He's a particle theorist, which is what interested me even as an undergraduate. By the time I was in my third year as an undergraduate, I felt that particle physics was the field for me.

Zierler:

And not just particle physics but theory; it was really theory that captivated you?

Wise:

It had to be theory. Oh, my god.

Zierler:

Yeah.

Wise:

I never completed my second-year lab course. I couldn't get the oscilloscope to work.

Zierler:

[laugh]

Wise:

In my senior year, I didn't have the requirements for a physics major, but I was, one of the very best physics students. I had a meeting with the assistant chair, because they wanted me to be a physics major. My summer job for a few summers was working at a factory, Industrial Wire Cable, in the lab. I would test cable. The department decided to use that work to satisfy my lab requirements so I could be a physics major. I have no talent experimentally and I liked theory, so I knew I had to be a theorist, for sure.

Zierler:

Mark, being an undergraduate in the mid, early 1970s, how well aware were you of the extraordinarily exciting advances that were happening in particle physics? Were you aware of what was going on at Brookhaven and SLAC and things like that, or was your experience a bit more parochial?

Wise:

I was not aware. You would think I would be, but I was very focused on my undergraduate training, the classes I took. I think it is a little bit of a mistake what we do now. The undergraduates are under tremendous pressure to do research. It's hard to get into top schools if you don't do that. I think having the deepest possible understanding of the foundations in the long run is more valuable. There wasn't that pressure back then, or at least, if there was, I wasn’t aware of it. As you said there was a huge revolution of particle physics going on, but it played no role in my choice of fields.

Zierler:

Did you write a senior thesis?

Wise:

I don't think I wrote a senior thesis, no.

Zierler:

What kind of advice did you get in terms of graduate schools? Did you specifically get advice, look to the United States, that's the best place for you?

Wise:

Nathan Isgur gave me the advice to look to the US, that's where the great expertise is. Lynn Trainor wasn't so sure about that, but he was not a particle physicist, Nathan was. So for that type of advice I listened mostly to what Nathan told me.

Zierler:

Where did you apply?

Wise:

Since he said I should go to the States, that is where the schools I applied to were. I was very naïve about the process, and I applied to just to Harvard, Stanford, Cornell, Princeton and I think Caltech and MIT as well. I thought that since I was the top physics major at University of Toronto I would get in. The application asked for an essay and I thought, who cares about this silly essay thing? So I wrote something that was not awesome.

Zierler:

[laugh]

Wise:

And then I got in nowhere. So I stayed for a master's at Toronto. Here's an odd thing, I don't remember being depressed at all after not getting in anywhere. I just thought I'll stay another year and try again. That worked out really well because I took this class on particle physics from Nathan Isgur and he taught me something called the nonrelativistic quark model. It was an old-fashioned subject by the time I was taking it, but, once you understand it, you can organize all the particles made up of quarks very easily. It gives you this powerful intuition for how things work. And because it was passé by the time I was starting, if I would've gone directly to Stanford I would have learned more fancy-pants things like the renormalization group, which, of course, I eventually learned, but I wouldn't have had this powerful intuition.

Zierler:

Um-hum.

Wise:

So I think, in the end, it worked out really well for me.

Zierler:

It was actually a productive year for you to stay back at Toronto?

Wise:

In the end, yes. I did learn things that proved to be very useful later in my career. I also spent some time looking up decay rates in the particle data book and trying to understand them. That helped me develop a way of thinking about things that also proved to be very useful. I was highly unsuccessful at understanding the patterns of decay rates listed there, but my attempt to do so was useful.

Zierler:

Did you take the essay application a little more seriously next time around?

Wise:

I took that more seriously. It still was not awesome, but I took it a little more seriously. [laugh]

Zierler:

[laugh]

Wise:

And you know how these things go. It's partly who's on the admissions committee. The second time around, I got into a few places. I don't remember which schools they were. I think I got into Cornell, Stanford, and MIT the second time around. It could just be the changes in the admissions committee. Hard to know.

Zierler:

Did you know Fred Gilman or know of him before you got to Stanford, or you developed that relationship after you arrived?

Wise:

It developed after I arrived. Fred’s research interests are very phenomenological, that is, connected to the data. Like most students, I thought I wanted to do something more high-falutin’, however, he was the only one who would take me as a student. He was the only one that had an opening at that time. But, again, it's amazing how these things work out. That's really where my talents lie. I don't know why I thought I wanted to do something more abstract given that I'm not great in mathematics. Of course, you have to be good in mathematics at a certain level just to have a career in theoretical physics. As an undergraduate I started off taking the mathematics course for math majors, but I had to drop down to the math for engineers.

Zierler:

[laugh]

Wise:

[laugh] A little humiliating, but still, you have to find your place.

Zierler:

Now, working with Fred, did you spend most of your time at SLAC, or most of your time in the department?

Wise:

Almost all of it at SLAC.

Zierler:

Yeah.

Wise:

Before I worked with Fred, I had an office in the Stanford physics department in the attic, but once I started working with Fred, I got a desk up at SLAC. He was a spectacular advisor.

Zierler:

What was his style as an advisor? Was he hands-on, hands-off?

Wise:

He was somewhere in between, I would say. He gave me a first project almost right away, and I think that's very important not to leave new students hanging. It was a good project, and doable. He outlined it very clearly so I knew how to start.

Zierler:

What was the project and was it related to what he was doing at the time?

Wise:

He would work on a variety of phenomenological things, that interested him. My project was on weak radiative hyperon decays. I had to model them as a single quark transition and then calculate relations between rates that you would get in such a model. Of course, as a student you're learning things. I would come in to see him and ask him questions. He was very busy, so it took some initiative to understand how to get his time. The method that worked for me was to come to his office five minutes before lunch. I would make him late for lunch. [laugh]

Zierler:

[laugh]

Wise:

I could ask him any question and he could answer it on the board without notes, explaining in detail how it worked. To this day, I'm not quite sure whether he has a photographic memory or whether he's one of these very linear thinkers. But, yeah, he was a great advisor. He gave me that first project and then, after that, I was able to find my own projects. Of course, I still needed help from him, so we would do them together. But that's the part in physics I think I excel at, finding interesting things to do. It sounds sort of silly, because the field always has these great unsolved problems, but they're really hard to solve. That's why they're the great problems.

Zierler:

Right.

Wise:

And so finding something solvable that's still very interesting is a talent. I think of it as the part of my skillset where I compare favorably with others.

Zierler:

Mark, to what extent did you utilize all of the exciting things that were happening at SLAC at the time to develop those ideas on your own?

Wise:

I went to the seminars and that was important. And, of course, at that time, the Standard Model was confirmed by an experiment at SLAC, and I found that very exciting. You feel the excitement around you.

Zierler:

Yeah.

Wise:

It really impacts your work. There were two great postdocs there that were generous with their time and worked with me, Larry Abbott, and Pierre Sikivie. Pierre Sikivie is the one that developed the axion search experiment, using cavities.

Zierler:

Yes.

Wise:

We’ve stayed in touch over the years. He told me that he was teaching E&M about cavities, and that's when he got the idea for that. Larry Abbott became a biologist. I don't know if you ever heard that name?

Zierler:

No.

Wise:

He's a really interesting guy. He makes violins as a hobby. He changed to biology and is in the National Academy of Sciences as neurobiologist. Amazing young people were at SLAC at that time, and I worked with some of them when I was a grad student. Larry and Pierre participated in mentoring me at that time.

Zierler:

Mark, how did you go about developing your thesis topic?

Wise:

I got interested because of some papers by Russian physicists that I read. In those days, there was no arXiv. At SLAC every week they would post the papers that got mailed to them. I don't remember exactly how it happened, perhaps because of the project Fred suggested to me, I got interested in weak decays more broadly. I read this paper by Ed Witten on how you calculate logarithmic QCD corrections the effective of Hamiltonian for such decays. Then I saw these papers at the SLAC library by Shifman, Vainshtein, Zakharov, and Voloshin, who unfortunately, passed away recently. They had done the QCD corrections to weak decays using four quarks. The top quark was not discovered yet, but everyone expected it. You didn't have a complete theory without it. I saw there was an opportunity to work out in more detail the CP violation in the Standard Model. In particular to, how calculate the logarithmic QCD corrections and work out the effective Hamiltonian for CP violating processes and to calculate the values of the measurable parameters that characterize CP violation in kaon decays. Fred might have also participated in this choice of topic, I don’t remember. It ended up a much richer subject than I thought. CP violation is very tricky because how you get it. Theories need coupling constants with an imaginary part. If they have a complex phase, you can get CP violation, but some of those phases are artifacts, they're artificial. You can just redefine them away, and so it was a little more difficult than just the straightforward calculation. I worked it out with Fred, for a parameter that characterizes direct CP violation in kaon decays and that got me into this area. What was really advantageous to me is it was an exciting area experimentally, and I became one of the world's expert in CP violation, well the SLAC expert, at least. So people would come to me and ask questions, for example bj [Bjorken], a great physicist, who probably should've won the Nobel Prize. Maybe he still will. Once he came to ask me a question. This graduate student that was sitting at his desk amongst 10 other graduate students was telling BJ how things worked.

Zierler:

[laugh]

Wise:

Knowing really well this particular area gave me a lot of stature within the group there.

Zierler:

Mark, being at SLAC, did you take advantage of any of the experimental advances; was that relevant at all to your research?

Wise:

For the CP violation parameter that Fred and I predicted, it was Bruce Winstein who was doing the experiments. He was at Chicago. There were no experiments directly relevant at SLAC, but the experimental program at SLAC really was important. It was exciting. They were confirming the Standard Model, and it provided the right environment, for the type of physics that interested me. At Princeton, my research direction might not have been as valued. Maybe it would have been, but it's hard to know. At SLAC it certainly was very highly valued to be connected with experiment as a theorist.

Zierler:

How did you know you had enough to defend? What was that process like?

Wise:

Oh, I knew. By the time I had done these things on the weak interactions, I was known in the physics community, I was the expert, and I knew it. So I had no question in my mind, even as a graduating graduate student, I would get a postdoc and probably a good faculty position after that, not necessarily at Harvard or Princeton or Caltech, but at a good place. My graduate work wasn't something that was going to win the Nobel Prize, but it was something that was clearly good.

Zierler:

Who was on your committee?

Wise:

Lenny Susskind, Fred Gilman, and I don't remember the rest of my committee. I remember Lenny because he asked me a question I couldn't answer.

Zierler:

[laugh] Do you remember the question?

Wise:

Yes, I remember the question. He said, "Show me how to do this with Feynman diagrams, not with effective Hamiltonians." And I should've been able to actually, because I knew it, but maybe I was nervous. And so I was fiddling around, and it wasn't going so well.

Zierler:

This presumes it could be done with Feynman diagrams.

Wise:

Oh, it can be done, yeah, absolutely. And then he said, "Oh, I see. Now I understand why you use this effective field theory method" [laugh]. My oral was fine. Everyone was nice. Your thesis defense in particle theory is usually not a big hurdle. By the time you get there you usually have more expertise than your committee on the subject of your thesis.

Zierler:

Mark, what were the most interesting postdoc opportunities and offers you were considering?

Wise:

I wanted to go to Harvard, and when I got that offer, I declined the others. For my postdoctoral work I wanted to change direction but still stay connected to phenomenology. Howard Georgi, Shelly Glashow, Steve Weinberg, and Sidney Coleman were at Harvard. They were some of the giants of the day, plus there was a big group of students and postdocs with phenomenological interests. I was in the Harvard Society of Fellows, which has a lot of prestige. Back in those days, it was the lowest-paying postdoc. They leveraged the prestige to control costs.

Zierler:

[laugh]

Wise:

It had this very peculiar aspect, I could eat anywhere on campus for free. [laugh]

Zierler:

[laugh]

Wise:

Even the faculty club. Of course, I had a great time at Stanford and a great time at Harvard, as well. Spectacular young colleagues there. We all got along and worked together.

Zierler:

Mark, do you have a sense who in the physics faculty really promoted your acceptance for the postdoc; was it Georgi?

Wise:

Oh, it was Howard, for sure.

Zierler:

Yeah.

Wise:

He's one of my heroes. His accomplishments are amazing. At the time I was there, I thought SU(5) grand unification, which Georgi and Glashow discovered, would be the correct theory, and that the new experiments coming on to test it would be the future of high-energy physics. In particular, that we'd work out the Hamiltonian for baryon number violating processes; maybe it wasn't the SU(5), but another theory. You have to look to nature to figure out what the correct theory is. I was very confident that would be the future, but it didn't end up that way. It still might be correct, not the minimal SU(5) model, but some variant of it. You have to have experiments that confirm it, otherwise you just don't know.

Zierler:

Mark, who were some of the key people you were working with at Harvard, both among fellow postdocs and faculty?

Wise:

So on the faculty I worked a little with Shelly Glashow, but I mostly talked with Howard. By and large, I worked with postdocs there. I worked a lot with Joe Polchinski.

Zierler:

Um-hum.

Wise:

With Luis Álvarez-Gaumé quite a bit as well. He is very mathematical. I also worked with some of the students, Mark Claudson, Lawrence Hall and Ben Grinstein. It was a remarkable environment for research. I wrote one very important paper with John Preskill who became my colleague at Caltech.

Zierler:

What was Shelly doing at that time?

Wise:

I don't know in general what he was doing.

Zierler:

Yeah, but with you; what was he doing with you?

Wise:

He realized that the long B lifetime told you something about the mass of the top quark. The B lifetime just got measured and it was quite long lived. Paul Ginsparg, Shelly and I worked out the lower bound on the top quark mass taking that into account. It was a pretty influential paper at the time. It was Shelly's idea, and it was fun to work with him. He's a great physicist, and a pretty laid-back guy. He'd walk into my office and we'd chat a little bit and do a little physics.

Zierler:

[laugh]

Wise:

You never could tell if he really calculated anything, but he knew what the answers were. [laugh]

Zierler:

Of course, you could've been a postdoc at Harvard without being part of the Society of Fellows. Was your sense that this was sort of grooming you to be a Harvard professor; was that part of the package?

Wise:

No, I didn't view it that way. In fact, I wanted to be at Harvard. If it would've been a regular postdoc and not the society that would've been fine. It was really the people, the faculty at Harvard, and the very strong postdocs that attracted me more than the prestige of the society.

Zierler:

What were some of the bigger projects that you did that you might not otherwise have done had you not been at Harvard?

Wise:

I transitioned my research there. I worked almost exclusively on weak decays at Stanford, and so my senior year as a graduate student I spent the time learning unified theories and other things. When I got to Harvard, supersymmetry at lower energies was kind of the rage. I worked on that, first with Luis Álvarez-Gaumé, who was a postdoctoral scholar, who ended up at CERN, and then with Joe Polchinski, who unfortunately passed away recently. Very sad. Those were the main people I worked with. I also worked with Ben Grinstein when he was a student. I think I gave him an awful time. We worked on this project—I feel so bad about it still. We could've written an excellent paper, but I decided it wasn't worth writing a paper on. Showed remarkably bad taste on my part, but he seems to have forgiven me for it.

Zierler:

Mark, so just to be clear, at this point, you're not really thinking about cosmology; this is really not yet on your agenda?

Wise:

I started thinking about cosmology at about that time. What started me in that direction was some work with Eddie Farhi and Larry Abbott. They were in Boston. Larry was still a physicist then. I think it was Eddie who came up with the idea for the project. I had to learn about inflation to participate. We wrote a very simple paper on how the universe reheats through particle decays. Pretty wimpy paper, actually, although it ended up influential. That started me thinking about cosmology. After that came the axion work with John Preskill and Frank Wilczek which was a much more substantial contribution. When I left Harvard, I was very interested in cosmology. In my first couple years at Caltech, I worked on cosmology and astrophysics almost completely. Good thing I changed eventually. I don't think I was getting tenure at Caltech for that work. [laugh]

Zierler:

[laugh] Mark, did you have any interaction with Alan Guth when you were at Harvard?

Wise:

Maybe a little bit. I don't remember for sure. In any case, not a lot for sure. I actually met him at Stanford.

Zierler:

Oh, you did?

Wise:

He was at visiting Stanford. I'm in my advisor's office discussing our work and he comes in and he says, "Let me explain this exciting thing I just thought of." That ended up being inflation.

Zierler:

[laugh]

Wise:

I'm listening and I'm thinking to myself, that's crazy, this early universe stuff. Of course, his work really changed things in cosmology.

Zierler:

When were you on the job market? At what point did you start thinking about faculty positions?

Wise:

In my last year as postdoctoral scholar, I didn't really interview or anything. People knew me. I got two offers, one from Berkeley and one from Caltech. I got married as an undergraduate, and by then I had two children. They were born in Boston. I grew up in an apartment, so I really wanted to have a house when I became a professor.

Zierler:

[laugh]

Wise:

It was important to me in ways that are hard to explain really. But if you grow up poor, it's sort of a sign of "making it," and I realized pretty rapidly it would be tough in Berkeley for me to get something "reasonable." Caltech had a housing plan. Caltech had a smaller group of colleagues I was likely to work with, but I had a lot of confidence in my own ability to come up with projects. I didn't feel I needed a tremendous amount of stimulation, but it's important to have faculty around of very high caliber that you can ask questions. Both Berkeley and Caltech had that. It is also important to get good graduate students so that they enrich you as opposed to being a burden for you, which both Caltech and Berkeley have. It was the housing plan more than anything else. At Caltech I could afford a house I wanted. Now I also feel there's a lot of advantages to a private school, that if I would've been more thoughtful, I would've realized earlier and that would've put Caltech ahead anyways. Berkeley is a great school. I'm sure I would've been happy there, but that's why I chose Caltech. Also, my wife, Jackie wasn't working at the time, which made a house even more important. It is easier with children when you have a private backyard that is fenced in. This was back in the day when having a spouse that didn’t work that was still common.

Zierler:

Besides housing considerations, who was on the faculty at that point at Caltech that would've been exciting for you to work with?

Wise:

So David Politzer would've been the one I would work with. Also, John Preskill came to Caltech at the same time and I had already worked with him at Harvard. Of course, Murray Gell-Mann and Feynman were on the faculty, but you don't imagine you're going work with a God.

Zierler:

[laugh]

Wise:

Howard Georgi, he's a demigod and I worked with him. [laugh]

Zierler:

[laugh]

Wise:

Not that it's impossible to work with them, but still it's not something that's in your imagination.

Zierler:

So Gell-Mann and Feynman were still active when you got there?

Wise:

They were still active. And I'll tell you a funny story about that. So when I got the offer from Caltech, Shelly Glashow came in to congratulate me, because as I said we had worked together. He said, "Well, now you're going to be working with the big boys." And I said, "Come on, Shelly, you're a Nobel laureate." And he told me, "Well, you know, there's Nobel laureates and there's Nobel laureates."

Zierler:

[laugh]

Wise:

Shelly wasn't one for humility too often, but there was an example of that.

Zierler:

Did you have interaction with Gell-Mann at Feynman at all? Were you able to work with them at all?

Wise:

Murray was very generous with the younger people. He would come out to lunch with us. But I didn't really work with him. I didn’t think I could come into either of their offices and describe my most recent idea to them. Once I was working on a project to understand the probability of cosmic voids with Mark Goroff, David Politzer and John Preskill. We were stuck on something that really was just an aspect of probability. Mark Goroff ran some numerical simulations for the probability of voids. It was in my astrophysics phase. Comparing with the simulations we found that our analytic results were off by a factor of 2, and we just couldn't understand it. So finally, David Politzer says, "I'm just going to go ask Feynman." He left us, and Feynman didn't exactly answer it, but he came up with the conceptual root of our mistake—he knew what was wrong intuitively. After he told that to David, we figured out where the factor of 2 was coming from. We were thinking about it for quite a while and Feynman put his finger on the problem almost right away. When you're younger, you think you're going to be like Feynman or Boltzmann, maybe not Einstein. Why not, right?

Zierler:

[laugh]

Wise:

But then, you meet some of those people, and you realize, at least for me, that there's something different about them. They are a notch above what mere mortals like me can possibly achieve.

Zierler:

Was Politzer working on asymptotic freedom at all when you first met him?

Wise:

No. He did that as a graduate student at Harvard in the 1970s. I didn't come to Caltech 'til 1983. We worked quite a bit together at Caltech, both on the astrophysical things and on heavy quark physics, when I started to do that.

Zierler:

Yeah, yeah.

Wise:

And, boy, he really was great to work with. He's a very deep physicist, and he really understands QCD. I didn't fully appreciate that 'til we started work on things related to the strong interactions.

Zierler:

Mark, what was your sense of the culture of promotion at Caltech? Was the idea that, as opposed to a place like Harvard, junior faculty would be supported and the momentum, unless there was some problem, was that they were on a path to getting tenure?

Wise:

That's correct. It's a very different system. The idea was to tenure the junior faculty unless it didn't work out. At that time Harvard and Princeton would treat them more like senior level, not postdocs, but somewhere in between that level and the faculty level. That policy gave Caltech a lot of advantages. If you had a faculty offer from Caltech versus Harvard, you might take the Caltech one given that your chances of tenure were much higher. But now I think Harvard's changed, Princeton's changed. It's all more like Caltech.

Zierler:

Mark, when did you really start to get involved with heavy quark effective theory?

Wise:

I first got involved in the work that led to heavy quark effective theory and heavy quark symmetry in 1988. It started due to a question from Joe Polchinski. It was either a phone call or an email, probably a phone call. He said, "You know, Mark, the bottom quark mass is much heavier than the QCD scale. Shouldn't there be some logarithms of the b quark mass that are relevant for B meson physics that you can calculate using the renormalization group?" Basically, people were used to logarithms of the W boson mass when you correct weak Hamiltonian to include strong interaction effects. Logs of the b quark mass for B meson physics, was more unusual because the B meson contains a b quark. However, the relevant dynamics was determined by much lower energies, the QCD scale. So there still should be and are calculable logs. Joe asked me that question or brought up that issue, and I started to talk with David Politzer about it and we figured it out. Indeed, there were logs that were calculable, and we wrote a little paper on it. We later found out that a similar paper had been written earlier by my Russian friends whose work was so influential to me when I was a graduate student. Anyways, we found those logs. I asked Joe once we figured it out, "Come work with us on this. There'll be more to do. It'll be fun." But he was very much into string theory and writing his book.

Zierler:

And Joe was at Texas at that point?

Wise:

I think he might've been at Santa Barbara but I'm not sure, to be honest. I don't remember when he came to Santa Barbara.

Zierler:

And in terms of your past interactions with him or what he knew your area of expertise was, what was your sense of why he came to you with this problem? What did you have to offer?

Wise:

We had worked a lot together on low-energy supersymmetry at Harvard, so we knew each other really well. We were friends, and, of course he knew I had worked on weak decays before I got to Harvard, in particular these Hamiltonians and the logarithms. I was amongst the world's experts in those issues, and he knew that. As I said we were close friends, so you talk to your friends.

Zierler:

What were some of the broader theoretical questions around this question that may have prompted this interest at the time?

Wise:

I don't know—from Joe's perspective I think it was just the realization that there were things related to nature you could compute that people didn't know how to compute and he thought that was interesting. He wanted to understand it. He didn't want to spend the time, given his interests in string theory then, but he wanted to understand it. He was happy for me to figure it out and tell him what the understanding is.

Zierler:

Was your perspective, was Joe's interest primarily coming from the vantagepoint of this was useful for string theory?

Wise:

No, not at all. He's a broad intellect or was— I hate having to use the past tense. It was intellectual curiosity about the strong interactions. Basically, in theoretical particle physics, there are not that many cases where new methods are developed that make contact with data, that influence the things that can be measured in a way that's somewhat novel. It is a rare opportunity in my field. Of course, in the long run, that is what it's about, making contact with nature, to know that that's the way nature works.

Zierler:

You've been dabbling in it up to this point. When did you get more involved in cosmology on a substantive level?

Wise:

It started late at Harvard. I wrote the paper with John Preskill and Frank Wilczek on the axion cosmology, and that continued at the beginning of when I was at Caltech. So it started at Harvard and continued into the first couple of years at Caltech where it became my major interest. A few years into my time at Caltech I got interested in a project in weak radiative B meson decays. After that, heavy quark symmetry came, and then, I just completely switched back to more conventional particle physics. That was all I basically worked on. At the beginning, it was just the logs, but then, during one summer maybe, or just a visit, at Toronto, I started talking with Nathan Isgur and we came up with the idea of heavy quark symmetry and being able to have different quarks, moving at a fixed velocity have their properties related non perturbatively by a symmetry. The field broke wide open because it enables you to say interesting things about weak decays and there is a lot of data on that subject. It was a great time for me. Almost every day I had a new idea of something important to do. And so that's all I worked on for a few years. More recently my interest has returned to cosmology, but I am still somewhat of a dabbler.

Zierler:

What has heavy quark effective theory allowed? I mean, the theory is what it is, but it's opened up new paths of inquiry that weren't possible before. What are some of those new paths of inquiry?

Wise:

So first let me just go over what its power is related to it. Before heavy quark symmetry, if you wanted to calculate the decay rate of a B meson, a B meson is made up of a b quark and maybe an anti-up or anti-down, and then a lot of gluons. It's a bound state. They're called hadrons when they're bound states of strongly interacting particles. Before the development of heavy quark symmetry and the methods related to it, you couldn’t really calculate B meson decay rates. For inclusive decays people had intuition that a proposed rate was the leading term in some expansion. For exclusive decays they had nothing, nothing systematic. Heavy quark effective theory, which includes heavy quark symmetry and the methods related to it, opened up the ability to make predictions. They were systematic in the sense that there were corrections you could classify, and in some cases compute. It was a revolution. Its power was so great that there was a lot to do just applying it without ever going outside that formalism. Just the application of it, understanding the subtleties in how you apply it, the new things you could predict, provided a wide array of opportunities. That went on for years. It also led to other things indirectly. It led to a greater appreciation of effective field theory, and I think things like soft-collinear effective theory, which is a different method applicable in a different context was influenced by the work on heavy quark theory. At some level, nonrelativistic quantum field theory is an example of an effective field theory that has a lot of similarities to the heavy quark effective theory, and that has been known about, in the context of electromagnetism, for ages.

Zierler:

Mark, a broad question about your increasing interest in cosmology. Do you see yourself as part of a broader trend of people who sort of grew up in particle theory and then went on into cosmological questions because that's where the most interesting stuff was happening?

Wise:

It started with Alan Guth —well, it actually started with Ben Lee and Steve Weinberg if you go back a little further. They derived a very famous bound on neutrino masses. Weinberg and Lee were early examples of theoretical particle physicists contributing to cosmology. The questions in early universe cosmology are so fascinating. There's something magical about it. You're thinking about these tremendously early times, yet there's potential observational impacts of those things today. I view particle physicists as the guardians of the laws of nature. We're the ones that are going to figure that out. Things like inflation, seems unlikely to me that they would come from the astrophysics community. Cosmology is part of my field. Of course, it has undergone an unbelievable revolution more recently. When I started to think about it, it was before the microwave background anisotropy was measured. There wasn't even a quadrupole, the dipole, which is just our peculiar motion, was measured. But once that started, oh, my gosh, just so much was learned.

Zierler:

You mentioned before about the questions surrounding your research agenda and your tenure application. What do you feel was really what put you over for tenure at Caltech?

Wise:

It was my expertise in weak interactions and my model building in low energy supersymmetry.

Zierler:

Uh-huh.

Wise:

I got hired at Caltech in '83, and I think I got tenure in '86, very fast, and before the development of heavy quark symmetry. I was already well known for my work on weak interactions, and I had done all these beyond the Standard Model things related to low-energy supersymmetry. I was in what was considered the group of top young people at that time. I might have had a tenured job offer that hurried up the process. I did get some other job offers, in particular one from SLAC, but I don’t remember if it was before or after I got tenure at Caltech. You would think I would remember such things.

Zierler:

[laugh]

Wise:

One way to get tenure fast, is in response to another institution offering you a permanent position

Zierler:

You were happy at Caltech, though; it was working for you?

Wise:

Yes, I was very happy.

Zierler:

Yeah.

Wise:

I think there's basically two kinds of people, there's the happy people and the not happy people. Of course, unfortunate circumstances can make you not happy even if you are a basically happy person. SLAC and more broadly Stanford is a great place for research, and Caltech as well. I think I would be happy at both. If I would've gone to Berkeley, I think I would've been happy there, too.

Zierler:

What's your teaching load been like over the course of your career at Caltech? Has it been heavier at times, lower at times?

Wise:

It's pretty steady. We are on the quarter system. The academic year is three quarters, and I teach every quarter and then get one quarter off every two years. That's not an overly demanding load and so it's fine. The real advantage of Caltech, at least early on, was I was on almost no committees, and I really hate committees. Oh, my God!

Zierler:

[laugh]

Wise:

There's never been a committee I didn't dislike, even the ones I was the chair of. For some reason I just can't stand doing them. You know, when you teach it's still physics.

Zierler:

Yeah.

Wise:

To teach your class you have to think through some physics. Of course, I realize the committees are necessary, but that doesn’t mean I have to like them.

Zierler:

[laugh]

Wise:

If I was a physicist of the caliber of Feynman, I would just say no every time I was asked to be on a committee. Eventually, they wouldn't ask me anymore, they would know better. I have to do them at some level, and as you get older, you get put on more of them.

Zierler:

What have been some of your most enjoyable undergraduate classes to teach?

Wise:

I like to teach quantum field theory. That was probably my favorite class but it was a graduate class. The undergraduate one I've taught the most is quantum mechanics, which is also a great class to teach. Junior level quantum, classical, and graduate level quantum field theory, those would be my favorite. I dislike the ones that are a one quarter introduction to an aspect of physics.

Zierler:

Mark, you've been at Caltech for long enough where you have some historical institutional perspective. I'm curious how Caltech undergraduates may have changed over the years, demographically, the kinds of things that they're interested in, that kind of thing?

Wise:

There has been a change. Certainly, there are more women at Caltech now than when I started, no doubt that that's a positive change. It was pretty terrible before. It made undergraduate life so skewed, it just was not right. At Caltech overall, we're roughly 50/50 men and women now. There has been a more subtle change which I'm still trying to understand. When I first came to Caltech, I would give very hard problems, not necessarily intellectually hard, but they involved a lot of detailed calculation on the problem sets, and that was sort of the norm. And at some point, there was a rebellion, the students just didn't want to do that anymore. I'm not quite sure why. It might be partly the pressure to do research as undergraduates. I'm not quite sure. The students seem to have less time for the problem sets than they used to. They're still working all the time. I don't think they're out partying or anything. We haven't managed to become a party school.

Zierler:

[laugh]

Wise:

So something changed there. Of course, they know different things. That's just the way the world works. Students would come with expertise in electronics when I came to Caltech in 1983; now they know software. But that's just the world changing.

Zierler:

Mark, in the way that you talk about your positive experience with Fred Gilman, I wonder what you might've taken away from that in terms of your style as a graduate advisor?

Wise:

Well, I'm certainly not as good as he was, that's for sure. He was also very friendly. My wife and I would go over to his house for dinner. His wife Barbara is a lovely woman who made us feel welcome there. Once we took their children to a Giants baseball game. One aspect of his mentoring style that I try to take over, is to give my students a definite first project that they often do in collaboration with me. That's what Fred did. I would talk to him about the project on weak radiative hyperon decays. If I was on the wrong track, he would straighten me out. So I try to work very closely with the students for their first project. After that I more or less treat them like colleagues.

Zierler:

Um-hum.

Wise:

I don't expect them to know as much as postdocs or faculty, but when we work on something together it is sometimes a very close collaboration, checking results frequently, having discussions to get over obstacles.

Zierler:

Who have been some of your most successful graduate students over the years?

Wise:

There have been many. I will just mention a few: Martin Savage, Roxanne Springer, and Iain Stewart. They all have lasts names that start with the letter S so maybe that’s the organizational principal behind this choice. I've had quite a few other good students over the years, and postdocs that worked with me, as well.

Zierler:

Did you keep in touch with Fred during the SSC years and were you following those developments closely?

Wise:

Yes, I keep in touch at some level even to this day, partly because I know the family. There is one thing about the SSC that I didn't quite appreciate when it was canceled. I thought, well, we'll have the LHC so it isn’t such catastrophic even for my field. But the LHC really isn't as good. The SSC would've gone to higher energies and that would've been much better for the field.

Zierler:

In terms of what, supersymmetry, beyond the Higgs, what are you thinking about?

Wise:

Beyond the Standard Model of physics more generally. The SSC would have had a greater discovery potential. Now we are probably going to be sort of stuck 'til we get the next collider. There will be the upgrades of the LHC at CERN which will help. There is no evidence for anything beyond the Standard Model at this point, and that has led to massive depression for some of my colleagues, even a little bit for me. We are still exploring physics at the weak scale. New physics beyond what we currently understand could be something more subtle to detect or just out of our reach. Of course, we had all these theories, low energy—

[Audio cuts out 1:02:53.8 to 1:05:57.0]

Zierler:

And we're back.

Wise:

Sorry.

Zierler:

No worries.

Wise:

My battery power ran out. I was downstairs watching my grandson before I came up for this and I was plugged in down there. When I came up, I was in a hurry, forgot to plug in up here.

Zierler:

Mark, the last thing that I heard you say was low energy, and that was it. About what the SSC might've found.

Wise:

Yeah. It might have been helpful to just be able to go somewhat higher in energy. We're roughly the weak scale now. Even though I worked a lot on low-energy supersymmetry, it should be assigned a low probability of being nature. Not zero or one in ten thousand, but nature is cleverer than us, so a low probability. I just think a little higher reach might've helped.

Zierler:

Mark, given the durability of the Standard Model, as a theorist, what are the theoretical assumptions or assertions that would give some level of confidence that, at these higher energies there is something beyond the Higgs, there is beyond the Standard Model physics?

Wise:

The main motivation for that was something called the hierarchy problem. When you have a quantum field theory, it's got parameters that you fit to data, and more or less, you think that, these parameters, should be allowed over a range; there shouldn't be anything peculiar when you fit them to the data. But it ends up in the theory for the Standard Model, at least if it lives inside something larger with higher mass particles, you have to arrange these parameters to one part in 10 to the power 30 to get the Standard Model Higgs boson to have the measured value. That just seems so peculiar. So that was the main motivation for new physics at the weak scale. That point of view was developed by Weinberg and Susskind—well, actually Ken Wilson even earlier, realized that fundamental spin zero particles have this issue. That was really strong motivation. There're no particles with zero spin that are fundamental particles except for the Higgs boson, and it has this problem. It was very strong motivation. There still might be new physics that resolves this issue. Maybe we'll see this new physics at a little bit higher energy scale than we are now, and that'll be a revolution that resolves this issue.

Zierler:

What were your perspectives when the Higgs was discovered?

Wise:

It wasn't clear it was just going to be the Standard Model Higgs with the couplings that matched the Standard Model. So I thought we might see some evidence of new physics there, but now everything looks Standard Model-ish from the LHC. All the couplings look normal, and that's where we're at. One thing about this hierarchy problem is that it's not a self-consistency issue. It’s really just something unattractive in the formulation, so it could be that we’re just not looking at the theory correctly. Maybe there's a way to set it up without this problem.

Zierler:

Mark, absent higher energy endeavors, since we are still very much in a post SSC world with no clear plan on what might happen next, in what way does astrophysics and cosmology contribute to searching beyond the Standard Model?

Wise:

Well, that's a really important observation that you just made. We have dark matter that we know exists. We don't know for sure if it's a new elementary particle. I guess it still could be black holes, although I think it's only a quite peculiar mass range that that's not ruled out. But assuming it's a new degree of freedom, that's our best evidence for beyond the Standard Model physics, so you want to explore that as much as possible. We have explored dark matter on various different fronts. There's the direct detection experiments – basically these large vats of something, and they look for dark matter interactions with that. Then, there are things like dark matter annihilating in the sun or just in the universe at large. So far, those experiments or observations have just put constraints on dark matter. It could be that dark matters interactions with ordinary matter are so feeble, that none of these things occur at observable rates. We know there's some physics beyond our current understanding if the dark matter is not black holes. That's why a lot of particle theorists have moved in that direction, and particle experimentalists as well. Bruce Winstein, who passed away a few years ago, worked on a CP violation experiment to measure the CP violating parameter that Fred Gilman and I first predicted the value of. He later moved to cosmology, in particular the microwave background. He did a sabbatical at Princeton and worked with someone there. He saw the excitement in cosmology. But I'm not saying particle physics is over or anything like that.

Zierler:

And for you, in terms of your overall research agenda, has cosmology, in terms of the amount of time that you spend on any one project, is that the main focus and how long has that been the case?

Wise:

So I'd say the last three years it's been my main focus, but I've done other things along the way that were conventional particle physics and I'd like to continue to do that. I have a funny attitude about this that's not shared, I think, by almost any of my colleagues. For a while, I might work on beyond the Standard Model physics and then one day, I'm shaving in the morning thinking about that physics and it just strikes me, oh, maybe all this is just not nature. I should do something that at least has some lasting value.

Zierler:

You mean that this is all artificial constructs that physicists have created?

Wise:

Yes. Maybe dark matter is not the particle I was working on, maybe it's something different. If you do beyond the Standard Model physics and you write down a model that ends up not being nature, your grade is zero. It's a failing grade as a physicist.

Zierler:

[laugh]

Wise:

I did really badly in school for a while. I want to pass now. [laugh] This is not a common attitude amongst my fellow theorists, but I strongly believe it's true. On the other hand, you’ve got to give it a shot, right? So there's some tension there. The way I resolve the tension is that I try to do something more concrete for a while. I'm never very formal mathematically in what I do, even when it's beyond the Standard Model physics. Of course, you can come up with clever ways to derive fairly model independent limits on the properties of dark matter, and that is interesting.

Zierler:

Mark, when did you get involved in using your interest in math and science towards finance and business questions?

Wise:

I got friendly with a Caltech undergraduate who did a summer project with me, and took a class from me, Vineer Bhansali. He went into finance on Wall Street. We kept in touch and we'd always talked about getting together and doing something together. Eventually he took a job at Pacific Investment Management Corporation in Orange County, in Newport Beach, a beautiful area. I came down to his office to talk with him about a project. I figured, it would be a hobby. Got to have a hobby at a certain age. When we met, Vineer said, "Mark, you're going to work on mortgages. We're very interested in mortgages at PIMCO." He gave me all these papers to read. I basically went down once a week, or once every two weeks. It was something different, I would work on a project that was of interest to the firm, Often, it became very interesting to me, and I would work very hard at on the weekends as well. Vineer was in charge of research at the firm, in addition to managing some portfolios. I read all these papers on mortgages. One time they had a meeting of the people doing the investing in mortgages, that I attended. It was fun, and, in the end, we wrote a little paper on prepayment of mortgages. If you have a mortgage in this country, a 30-year mortgage, you don't have to keep it for 30 years; you can pay it off if interest rates drop. That dramatically affects the value of mortgages to someone who wants to buy a mortgage as an investor. Basically, the mortgage is more valuable if interest rates drop, Let's say, and they're paying you 6% on the mortgage and interest rates are 3%. It's an awesome thing, but they might just pay it off, so it is less valuable than if they kept it longer. You have to understand prepayments very well to price mortgages. I remember reading a paper from Lehman Brothers that says that there's people who would never refinance, even though it was advantageous to them financially to do so. I'm reading this paper discussing these odd folks who never prepay even when it is advantageous for them to do so, and then it dawns on me, oh, my God, I'm one of those people!

Zierler:

[laugh]

Wise:

I've got, like, a 9% mortgage that I assumed when I bought my house, and I could get something for—I don't know what it was then—like, 6%. That was kind of funny. Eventually we wrote our paper on prepayment. We realized that you could do something analytically for the last people in a mortgage pool, the last to prepay. They're called people with a low propensity to prepay. We derived a formula for that rate, at late times. Bond firms run these very numerically intensive models. There's a lot of data on whether people prepay, and they use that to develop mortgage prepayment models. We ran the PIMCO model and compared with our result, and it agreed. I was all excited. I figured we had done this great thing in finance. We never could get that paper accepted for publication. The final referee's report, which I thought was pretty good, said, "I think this paper's correct. It's kind of interesting. But I don't see how you can make any money off of it." [laugh] It was good referee’s report. We had a formula for the last people in the mortgage pool, to prepay towards the end of the life of the mortgage, but who cares about those people.

Zierler:

[laugh]

Wise:

I had a very good time and I enjoyed it a lot. I learned a lot about finance. There were other things we did that were more useful. I was never a big player as a researcher in that area. There are really smart people doing that full time, not as a hobby. Particle theorists are kind of arrogant, but I soon learned that people in that field were really smart and did very creative things. I'm sure I'm one of the few particle theorists who admires people from economics.

Zierler:

What about things like picking stocks and that kind of thing, did you ever get into that?

Wise:

Not as part of my work at PIMCO, but I went to lunch with the other people in the research group. They would talk about their investments sometimes. The way we might talk about other parts of physics, not related to our work during lunch. I learned some about investments from those conversations and I started investing a little bit of money on my own. PIMCO was a bond firm, so I mostly did things with bonds. You can make good money in bonds, if you know what you're doing, or at least you could. It's harder now. At one point I had this idea that oil prices were going to go up, so I put some money in oil companies, Canadian ones in the oil sands that never made any money. Of course, when the oil price went up, they made tons of money and I felt I was a genius. I seemed to do everything right. I remember going to lunch one time and sitting at the counter. It was a lunch counter but not on a campus, and these people beside me started asking me about oil prices. You know the stories about the shoeshine boy asking you about stocks in the roaring twenties. I figured, this is the end.

Zierler:

[laugh]

Wise:

I sold everything, and the oil price crashed shortly after. I had that very awesome beginning, which I've never been able to replicate.

Zierler:

But it's mostly fun; just a hobby?

Wise:

Even though it was always a hobby, I worked very hard at it when there was an idea for a paper. I got a consulting fee when I went down to PIMCO, but I hardly went down. There was never much money in it for me. That made it easy to stop doing it if I decided that is what I wanted to do. Eventually I got a new administrative task that didn't leave time for finance research, so I stopped. But I still do a little bit with my own investments. I'm not particularly good at it, but it's fun to think about.

Zierler:

It's obvious how you would've come to this from the vantagepoint of physics, but is there anything you've learned about the world of finance that has been helpful in the way that you think about physics?

Wise:

I don't know. I think financial economics is a lot like physics.

Zierler:

In what way? What do you mean by that?

Wise:

They build models. The models are true under certain assumptions, and they explore their consequences mathematically. Setting up the models is hard, requires creativity. And, in fact, when quantitative finance took off with the development of option pricing a lot of firms would prefer to hire physicists to do that research because the model building and the mathematical creativity had a lot in common with physics. I just found it very similar. I wasn’t going to be a big player in finance but I had a lot of fun.

Zierler:

Mark, what did it feel like when you won the Sakurai Prize?

Wise:

It felt good and I'm proud to have won it, but I'm at Caltech, so there's a high bar for standing out.

Zierler:

[laugh]

Wise:

[laugh] I'm not going to reach that bar. It's nice to be recognized by your colleagues. Of those type of things, being elected a member of the National Academy of Sciences was also very significant to me.

Zierler:

Has the National Academy, besides just being a great honor, has it been useful to you in terms of connections that you might not have otherwise made?

Wise:

It could have been if I would've been more active in it. I have a hard enough time just doing my research and making some progress there. I haven't taken advantage of my membership.

Zierler:

Mark, for the last part of our talk, I'd like to ask a few broadly retrospective questions. The first is just the idea of things that were really not known in the beginning of your career relative to where they are, and then the ongoing mysteries, the things where there might've been a lot of optimism 30 or 40 years ago and yet we seem to be stuck not much further than where we were then. So in terms of the real discovery, the real answer to some of those question marks, what stands out particularly with regard to your research and then the broader fields that you represent?

Wise:

So with regard to my own research, I would say my most important contribution was the heavy quark symmetry. It allowed you to do things you couldn't do before. It's a tool, but it is not a new theory. Within particle physics, the lack of something new at the weak scale that relates to the hierarchy problem is a disappointment—well, disappointment is too strong. We learned something deep about nature. We discovered the Higgs particle, but, as a theorist, you want to participate in the next revolution. That didn't happen. Earlier on in my career it didn't happen with baryon number violation, which I had mentioned to you. In cosmology, there was a revolution in the level of understanding that occurred on my watch. I left that field, while most of that revolution was occurring to work on heavy quark symmetry but it was a huge development in science. Cosmology could be entering a phase like particle physics, though. They have this picture, dark energy, for which the leading candidate is a cosmological constant. A cosmological constant is peculiar like the Higgs mass is, but it's certainly not what you would call beyond the Standard Model physics, it's allowed in classical gravity. So it could be that the picture that dark matter is a new elementary particle and the dark energy a cosmological constant is correct. We don't know what the dark matter is but we could just get stuck there if its interactions with ordinary matter are very weak. That picture is consistent with everything, of course, there are always these inconsistencies. I have a high bar for when those discrepancies are an important problem in astrophysics and cosmology. It’s not like particle physics. You can't repeat the experiment over and over. I remember when there were two determinations of the Hubble constant, one was 50 and one was 100 in some units, and they both had small errors. It ended up, having a value near 75. It is pretty hard except for special cases to really pin things down in astrophysics. The microwave background seems to be one of the cases where you can with a high level of precision. I don't know, we'll see what the future brings in that field. In particle physics, we have gotten used to revolutions. We had it in the '60s, with many particles being discovered, and the SU(3) symmetry of Gell-Mann bringing order out of chaos. Again, in the 70s, a revolution started by the discovery of asymptotic freedom and the charm quark. We could go 50 years, 100 years without another one. Larry Abbott, who is the friend I mentioned earlier used to tell me, "You know, Mark, particle physics is not like electromagnetism. Not everybody has to know it."

Zierler:

[laugh]

Wise:

[laugh] So maybe if I stay healthy and live a very long time, I will be the last of my kind, remembering what the revolutions in particle physics were about.

Zierler:

[laugh]

Wise:

Well, let us hope there are more in the near future.

Zierler:

Mark, just to bring the conversation right up to the present, how did you get involved more recently in conformal Fermi coordinates?

Wise:

I had been working on non-Gaussianity in the distribution of the mass density in the universe. Primordial non-Gaussianity that might have been generated during an inflationary era. I think it's one of the exciting possibilities in cosmology. If we observed it, we could learn more about the degrees of freedom that played a role in the very early universe. There is this brilliant work. I won't list all the authors because I will forget some. They found that some of the non-Gaussianity that you compute, is really not there. You have to go to the right frame. If you go to that frame, you see that it is absent. Of course, you never really have to go to the right frame because we have general coordinate invariance. However, it might be that to formulate what you observe in a general frame is just very awkward but it’s simple in the right frame. That frame is conformal Fermi coordinates. I knew about this, but I'd never studied it, and I really wanted to understand it because it's a very deep thing related to non-Gaussianity. It certainly should be in all the textbooks if they write another generation of cosmology textbooks. With my student, Adriano Testa, we decided to understand it better and work on a project to facilitate that. In the models people had looked at going to the right frame cancels out the non-Gaussianity. We thought, well, let's have the project be finding some kind of non-Gaussianity, where going to the right frame is an important effect, but it doesn't cancel everything out. We found an example of that and worked it out.

Zierler:

Mark, last question. Looking to the future, to come back to the importance of mentorship and the benefits that you got from Fred Gilman, one of the best ways to really put your money where your mouth is in terms of where the fields are going is the way that you approach mentorship with your graduate students, because it's really their careers that are on the line, in terms of the most fertile areas for fundamental discovery, right? And so, on that basis, given your broad range both in theoretical particle physics, cosmology, things like that, where are the areas in physics where you are optimistic for that fundamental discovery? Where are those places where—obviously, you always want to encourage your students to follow their interests, but in terms of being confident that there's the next theory, there's the next experiment, there's the new way of thinking about things, there's the impact of AI and quantum computing, all of the above, what are those areas in physics from the fields that you represent where you're most optimistic for the next generation?

Wise:

First of all, there are the things that I am personally interested in that match my tool set. Quantum computation and quantum gravity for example doesn’t fit that bill. In particle physics and cosmology, there'll be new developments. Weak decays were around for 20 years and then came heavy quark physics. There will be tools developed, there'll be new insights. I'm not worried about the field drying up right now. When a student comes to work with me, I will be working on something that interests me. They know what it is, and if they want to think about that, then I'm happy to take them and work on that with them. I don't really worry about the long-term future. They are just starting. I worry about whether they will do something interesting enough in that area to get a good postdoc. After they get their postdoc, they might change what they do. I want them to get that first postdoc and do well, but I don't worry about long-term issues like that with the mentorship of students. It's really, do I have enough of a set of ideas to give them that first idea and stay active enough that I will be a good mentor over the time that they're working with me? Another thing is, it's kind of a difficult thing for me to say—you know, I'm 67 now. There's a question of retirement. Supervising a graduate student is a five-year job, so if I take a new student, I'm committing to being at the forefront of my field for five more years. I hope I will be, but it does worry me a bit, actually.

Zierler:

Because your responsibility to the graduate student is you need to be at the cutting edge of the research so that you can present those problems to your graduate students, otherwise it's a disservice. You have a moral obligation, essentially?

Wise:

That's correct. For the first project certainly. Even though I expect them to be finding their own projects and broadening out, I think I have to be able to participate at the highest level throughout the whole time they're my student. That is a responsibility for sure.

Zierler:

So you always have a five-year plan you have to operate on?

Wise:

I don't need to have projects that span five years, but I have to think about whether I'll still be creative enough and engaged enough that I can come up with them.

Zierler:

Right.

Wise:

I also have to stay sharp enough to see when they are making a mistake, even a subtle one. Even really good physicists make mistakes. I remember the first important paper I wrote on CP violation with Fred Gilman, as I said, CP violation has all these subtleties with phases. We sent it to John Ellis and Bruce Winstein. I remember John Ellis, at least I think it was John, got back to us. He had written a paper on CP violation—Ellis, Gaillard, Nanopoulos—before ours. It wasn't as detailed. It was sort of a general brush. He wrote back that he thought that what we did wasn't right, and that we had not correctly taken into account this phase freedom. He was right. So we fixed it up. He didn’t work through everything we had done; he just knew. I want to be sharp enough so when a student comes to me, I can know if it’s right. That's an issue in the back of my mind. There is another example of this. I've been helped along the way a lot. It's amazing how giving people are. They really care about getting the physics right. John Ellis came to visit SLAC, and I had written a draft of a paper on my own on inclusive B decays, a B meson that goes into a psi particle and anything else. I gave him my notes on that, and he said that he thought that there was a mistake, and he was right. I fixed it and submitted the paper for publication.

Zierler:

[laugh]

Wise:

Yeah, there you go. I'm wrong a lot, at least not in the final product. There are a few cases where the mistakes made it to the final product and an erratum was required, but not many.

Zierler:

[laugh] Well, Mark, on that note, it's been great fun speaking with you today. I'm so happy we were able to connect. Thank you so much. I really appreciate it.

Wise:

Yeah, you, too. It's been fun.

[End]