Frances Hellman

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ORAL HISTORIES

Photo courtesy of Frances Hellman

Interviewed by

David Zierler

Interview date

April 25, 2021

Location

Video conference

See catalog record for this interview.

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Interview of Frances Hellman by David Zierler on April 25, 2021,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
www.aip.org/history-programs/niels-bohr-library/oral-histories/46802

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Abstract

Interview with Frances Hellman, professor of physics and of Materials Science and Engineering, Dean of Mathematical and Physical Sciences at UC Berkeley, as well as senior faculty scientist at Berkeley Lab. Hellman is also president-elect of the APS. Hellman explains why she considers physics her “home” department and why her research agenda spans so many disciplines. She describes the major issues in her incoming leadership of APS and how Berkeley has coped during the pandemic. Hellman recounts her childhood in Manhattan and then Brooklyn and she describes her Quaker education and her early interests in science. She describes her focus on ski racing and her undergraduate experience at Dartmouth, and the formative influence that Bruce Pipes had on her development as a physicist. Hellman discusses her motivations to pursue thesis research at Stanford, where Mac Beasley and Ted Geballe were her co-advisors and where A15 superconductor research was in full gear. She describes her postdoctoral appointment at Bell Labs to work on magnetic thin film materials and magnetic superconductors. Hellman conveys her interest in entrepreneurship and the opportunities that allowed her to join the faculty at UC San Diego, and she describes building up her lab and her interests in thermal links. She reflects broadly on the basic and applied aspects of her research, and she explains her reasons for transferring to Berkeley and her affiliation with the Exploratorium. Hellman describes her administrative responsibilities as department chair in physics and she conveys her recent interests in amorphous materials and specifically ideal glass. At the end of the interview, Hellman discusses her involvement in both the APS and Berkeley’s efforts to make STEM more inclusive and diverse, and she describes her optimism that her work on amorphous materials will lead to key discovery in the field.

That’s a great question, and actually an important question, too. I consider myself first and foremost a professor of physics. Way back when I was applying for jobs, when I was a postdoc and looking for assistant professor positions, I applied for jobs in quite a range of departments, mostly physics but also some materials science, materials science and engineering, I think one chemistry department, and one or two electrical engineering departments. That’s because my research really could lie in any of these departments. I'm a condensed matter experimentalist and my research lies at the intersection of all these fields. I mostly do research in magnetic materials. But that being said, for the last quite a few years, most of my research has involved amorphous, meaning non-crystalline, materials. And in the last about ten years, I've been doing a lot of research on non-magnetic amorphous materials, specifically insulators. That’s its own topic and has led me to having an affiliation with LIGO, for example. I'm now an official member of the LIGO team, and I work on improving their mirror coatings, which are insulators.

So getting back to your question about affiliations, when I was applying for jobs, I reached the decision that I loved teaching physics. And that’s still true. I probably could be in any of these other departments, but I love teaching physics, and I love having physics as a hobby as well as my job. I love learning about all aspects of physics. The breadth of physics, I just find remarkable. So I love being aware of that. I love going to colloquia. And since I love teaching and learning about physics, the natural thing for me is to be in a physics department.

That being said, my graduate students come from a range of departments. It is common that I have graduate students from materials science and engineering—MSE, to use the abbreviation. It’s common for me to have about six graduate students, and of them, right now I have three from physics, two from MSE, and one from electrical engineering. And that’s pretty common. At other times in my career, not that long ago, I had two from chemistry.

Great question. I get invited to soft matter conferences to speak on my work on amorphous materials and ideal glasses and topics like that. Many of my talks are in sessions on soft matter, and many of the people that I talk with, particularly the theorists that I talk with about the ideas around ideal glasses and related, call themselves soft condensed matter scientists.

I don’t tend to call myself a soft condensed matter person, even though I'm working on non-crystalline materials. And that’s in part because one of the aspects I'm most interested in in amorphous materials is what one might term a hard-core condensed matter topics, meaning correlated electron physics. I love the fact that I observe in amorphous materials what most people regard as properties that you only find in crystalline materials, and I love showing that the theory underpinning the understanding of those properties are therefore an incomplete understanding. Amorphous materials don’t have Bloch waves and we lose our mathematical approach to the condensed state, represented by Bloch waves and periodicity — yet we have virtually all the properties that we are trying to describe with Bloch waves. I have shown that some fairly hard-core properties, like topological insulators and Berry phase curvature, which are topics whose theories rely on the periodic lattice and reciprocal space, are found in amorphous materials.

The thing you don’t have in an amorphous system is reciprocal space; k is no longer a good quantum number. At least as a vector, it’s no longer a good quantum number. Energy E is a perfectly good quantum number, but momentum k as a vector is not. But you find the same phenomena. What I love about that is that you're forced to think about these phenomena slightly differently. You're forced to think about them in real space, for example. You have to think about real space analogs to what you normally talk about in reciprocal space.

We're getting a little far afield, perhaps, but the example I love to use for this is superconductivity, which in the original BCS theory relied on plus-minus k-state pairing. That original formulation of BCS theory is completely a reciprocal space description. [An] electron traveling one way pairs with an electron traveling the other way. And many people don’t know this, but there are amorphous superconductors. There are amorphous superconductors that have significantly higher TC than their crystalline counterpart, molybdenum being the best example that I know of, which is around one Kelvin in its crystalline state, and around seven Kelvin in its amorphous state. This forced a generalization of the superconductivity theory. It was no longer plus-minus k- state pairing; it’s time reversed states. Leading to this beautiful description in which one electron travels through scattering essentially every mean-free path. And a time-reverse of itself travels back through that path, just like light would, through a bunch of scattering events. No matter how complicated the mirrors—as long as there’s no inelastic event. Those time-reserved states are what actually pair.

And that may sound like a purely mathematical generalization of BCS theory, but it leads to very deep insight. Superconductivity is a remarkable phenomenon. Many refer to it as an emergent phenomenon. It doesn't care about the details of the underlying structure; the coherent electron state emerges, as a pure wave function. Isn’t it more amazing that some material (like amorphous Molybdenum) superconducts where in its normal state the electrons scatter at every atom—meaning that the mean-free path is like one and a half angstroms in the normal state, and when it goes superconducting, it goes into a state where the paired electrons don't scatter at all—well, the specifics of what they are doing, you have to think about a bit, but the pairs travel coherently in a single wave function.

Zierler:

As if there weren’t enough challenges to deal with!

Hellman:

Hellman:

Yep, exactly. And there’s a range of scientist careers. Some of us are researchers at R1 universities. Others of us teach high school science classes. Others are science advisors to like politicians, or are lobbyists on behalf of science, or patent lawyers. All of industry is filled with scientists that are needed for technological advances. There’s a huge range of careers. I'm a very strong believer that it’s not a hierarchy. It’s not like the people who are academics at the top universities are somehow the top of some hierarchy. All these people have important strengths and are valuable to our society.

I am, in some ways, very smart, and I have a good memory for things, and I have a good knack for working out how to do things. But there’s other ways in which I am not as smart as other people —my husband Warren, for example, is much smarter than me about various things. And it’s quite funny when I suddenly realize this. For example, I don’t recognize people, for example, very well. And he’s like, “We just saw them yesterday.” Or, “We just heard them on the radio yesterday. How do you not remember that?” That’s not my skill set, apparently. People have different talents, and we have to learn to value them.

Zierler:

Frances, I'll ask one last question that’s in the moment, then we'll go back and develop your personal narrative. In light of your deanship coming to an end in late June—and as you say, of course, COVID happened and that overtook everyone—obviously there was no playbook for what we all dealt with over this past, what are we, now, fourteen months? Something like that. What do you wish you knew now at the beginning of this pandemic, and how would you grade yourself in terms of your part in guiding Berkeley as best as possible through this multifaceted emergency?

Hellman:

All right, I'm going to answer this in two parts. I will talk about the Berkeley part first. One of the biggest challenges in COVID was not knowing how long it would last and what we were going to have to do. So we spent so much time creating plans that never got implemented. Just constantly, constantly creating plans for—“Oh, maybe we'll be able to start in-person classes at the start of Fall semester.” Nope, that’s not going to happen. “But maybe we can have in-person classes starting at this other date.” Constantly planning for things that didn't happen, so that everybody was just working much too hard. And I don’t know if we could have let that go, but in hindsight I wish we had.

To tell you a related story from when I moved to Berkeley—I was a professor at UC San Diego from like 1987 until 2004, and I moved to Berkeley in 2004. And when I moved, my laboratory wasn’t ready, but I had a research group. I said, “While my lab gets done, I have to have a laboratory.” So they gave me this little room, down on the basement floor. And I picked two or three experiments that I wanted my group to be able to do, while my lab got built. And we worked so hard. My whole group, we worked so hard, in that little tiny space, which had not enough ventilation, so the pumps kept turning themselves off because they were overheating. And in the end, we did do one experiment. We measured the magnetoresistance of amorphous Gadolinium-Germanium. It was a key point for a paper that we finished. And I was so excited about it. We did it in this horrible, little tiny space. And I put the data on my office door—“We did this!” We spent almost a year, and we got one experiment done. In hindsight, perhaps I should have just sent everybody home. I should have told them to just take a vacation. Just take a break! Do some reading, so something. But I was so determined that we were not going to shut down for the year.

I felt like this time of COVID has the same element. We were so determined to not shut down. But we were all running around a lot. And I don’t know that we could ever have done this differently, because I don’t think it was ever going to be possible to just say, “Oh, well, we're just going to go home and—we'll just pay you all somehow, but we're just going to wait to see when we can reopen.” There’s a part of me that wishes we could have just waited to see when we could reopen. I don’t know if that’s really a lesson learned. I don’t think we could have done it differently, but it was painful, how much effort got spent, with little effect.

Personally, I remember the day we got sent home. I was in my office at Berkeley. I think I walked home. It’s about a 40-minute walk. My husband was off doing his job. And I was mildly excited about the whole thing. I had all these plans. I was already busy thinking through what projects I was going to give to each of the students in my research group to keep them productive. I had a plan for every student. We're setting up a new scanning calorimeter, and so a couple of them were going to do simulations of the thermodynamics of the nano calorimeters that we needed. Others were going to do density functional theory calculations of electronic density of states in amorphous topological insulators, a topic I'm interested in, etc.

I had all these plans for what each of the students was going to work on, and I was slightly excited because I thought of all the things I was going to do. Like for example [laughs] I remember I was going to clean up the house. I was going to finally get rid of all those extra clothes in my closets. I was going to learn the mandolin. I am a member of a family band, and I don’t play an instrument; I am vocals only. But I have been under a certain amount of pressure for quite a while to learn an instrument. And so I have a mandolin that I borrowed from somebody. And for the past about three years now, I have been paying $20 a month to an online mandolin teaching class, but I have not participated in a single class. Not even one. I have literally not even logged in once. But I every month pay my $20 dutifully.

So as I was walking home, I'm like, “I can finally do this.” I was on my way home, and I had all these plans of what I was going to do. And here we are, 14 months later; I still have not done a single mandolin lesson. The house is definitely not cleaner. So what lesson would I personally take from that? I guess maybe give myself a little more of a break? I don’t think any of us knew how long this would go on. I remember being all excited that I had a freezer that had two pizzas in it. I thought, “Oh, that’s great. I'm all set for food for a little while, because I've got two pizzas in the freezer.” And of course, that’s not even a month. The things you think at the beginning are going to be helpful to you—we've learned all kinds of things, how to do all sorts of things that we didn't know how to do when we started.

Zierler:

I'll just share with you that at the beginning, I was going through the same thing, trying to figure out what I was going to do now that I'm not traveling and interviewing scientists in person. I reached out to top-ten department chairs in physics, asking, “Who’s emeritus that would be great for me to interview on Zoom? I've never done that before. Let me do it now. That’ll keep me busy for a couple weeks.” One of them was—I got in touch with Wick Haxton, and as a result, John Clarke, Mary Gaillard, and Marvin Cohen. And I thought, “Wow, this is amazing.” And then, here we are; I'm just doing everybody now. [laughs] Frances, let’s take it all the way back to the beginning. First, let’s start with your parents. I know this is a very interesting story. Please tell me about them and where they're from.

Hellman:

Oh, gosh. Well, they are interesting. There is no obvious science in my past, in my heritage. My dad was born and raised, more or less, in San Francisco. His parents were interesting. His mother in particular—Ruth, my paternal grandmother—was a WAC, Women’s Auxiliary Air Corp. They flew planes in World War II. They mostly flew supply planes, but then I've also heard stories of them flying target practice. They would haul the banner behind that the other planes would shoot at. And she had amazing stories—like they’d be shuttling planes from a factory across the country. In those days, planes did not fly all the way across the country. So they would land somewhere, and the military commanding officer would say, “What the heck is going on here? Women don’t fly planes.” And he wouldn't let them take off! [laughs] And they’d have to call Washington to get permission for them to refuel the planes and take off again. She was an amazing woman. She died when I was relatively young, scuba diving, when she was about 60. She was remarkable.

My dad was a native San Franciscan, and my mom was British. She grew up in England, a wartime child, World War II child. She was a dancer, so she stopped high school when she was 16, after she took the A-levels. Which you take when you're 16 in Britain, to enable you to go to the university. Her father would not let her stop school to become a dancer until she passed her A-levels, which she did, then she stopped school and danced professionally. She was a soloist with the London Festival Ballet. She and my dad met on a boat, transiting the Atlantic. My dad went to UC Berkeley, and he was doing a junior year trip abroad with his buddies, and so they were on a boat traveling to England, and from there to Germany and so forth. And my mom was returning from a set of ballet performances in the U.S. And so they met on this boat.

And over the course of the next two or three years, they saw each other twice [laughs] for like a week each time. She went to San Francisco one time on tour, and she stayed with his parents. And he went one more time to London and more or less courted her. This was over the course of three years. They had about two weeks together, and then he sent her a telegram saying, “Will you be Mrs. Hellman?” And she said, “Yes.” And so they got married, then she flew across to the United States. And in those days, there were phones, but it’s not like you routinely went home at that point.

My father was very non-technical, a very successful businessman. A very entrepreneurial kind of businessman. He believed in investing in people. He would find somebody he believed in, and then invest in them. He did well by himself and by them. Nobody on that side of the family has any technical background—many are bankers, and there’s some lawyers in there, things like that.

So I've always been of the belief that it was my mother who had the innate science skills, but never expressed, because she left high school at 16. She always believed herself to be terrible at math, but I just don’t believe that.

I'm the oldest of four, there’s four kids in my family. I was born in Britain, so presumably could never be president. Although I've never been clear on that, because I was born of U.S. citizens while my father was in the military. But I have no interest anyway in being the president of the United States. We should be clear on that.

Zierler:

Well, you say that now. Let’s see after APS. Maybe you'll find out.

Hellman:

Yeah, yeah. [laughs] My dad was in the military, so it seems like a little funny to think that if he’s in the US military stationed in Germany—

Zierler:

What does your birth certificate say?

Hellman:

It’s a British birth certificate. It says I was born in a British hospital—because my mother went home to England to have me. But we went back to Germany, to the army base Dad was stationed with by the time I was 6 weeks old. I have a giant smallpox vaccine on my arm—huge—like the size of a quarter—because my smallpox vaccine was done in a U.S. Army base, and they don’t routinely do children. And then each of my sibs was born as my parents moved around. My dad went to business school at Harvard, and so my sister was born in Boston. And then the next two siblings were born in New York, where he then had a large fraction of his career.

It’s an interesting thing to look back on now. That whole thing with my sequence of ski-racing colleges—I got into Dartmouth, so I went to Dartmouth. But I was quite adamant when I went to Dartmouth that I was not going to take money from my parents. Now, the privilege part of this, which I've come to recognize since—it’s kind of a privileged statement—I did not, in fact, take money from them. They never sent me a check. But they did pay my tuition, and they did pay my room the times that I had rooms in the university. But I always had jobs, and whenever I was off-campus, then I would pay my own way. And I always paid all my own clothes, all my own books, all my own optional things.

I had jobs the whole way through college. I worked at Dunkin Donuts for a quite a while, which was one of my more interesting non-technical kinds of jobs. So I didn't recognize my privilege—I look back on it now and I say, “Wow, I had privilege that I refused to admit.” I was determined that I was going to make it on my own, and I did not need my parents’ help. Growing up on the Upper East Side and going to a private girls’ school —there’s a lot of angst going on now in that school about what that meant, and how terrible we all were around the very few people of color who were in that school.

There’s a way in which, when I was growing up, having money was viewed as a bad thing. So I very much incorporated that into the way I thought of myself and my family. Having money, meant you weren’t making it on your own. And I always thought it was quite ironic that the people who would say this —in modern language, the one-percenters— first of all usually don’t recognize they're one-percenters. Secondly, half the people who were protesting against the one percenters actually are in the one percent; they just don’t want to admit it. That was very clear to me even when I was a child, that the people who were being dismissive —“You, oh, your father has money”—they were very privileged, also. So it was complex, growing up. And it did lead me to feel very strongly that I wanted to make it on my own. So a complex question you've asked there.

Zierler:

Now, when you got to Dartmouth, is it a gradual process whereby science becomes more important to you than skiing?

Hellman:

Science actually became important to me while I was still in high school. I had an interesting and kind of weird high school experience, mainly because of the ski racing. Ski racing was incredibly important to me. I was attending one of these private girls’ schools in NYC, and there was a moment in tenth grade where I qualified for the Junior Nationals, which is quite competitive. And it happened that the Junior Nationals—or maybe it was the Junior Easterns, which is the predecessor to the Junior Nationals—was during exam week, or perhaps during exam preparation week.

I was at that point doing this hybrid thing. I was attending school in New York City, but I would be gone to Vermont from October through April. My parents and one other family had started this ski racing academy, which was a tutoring system, basically. There were around 15 kids, and we lived in these two houses; a girls’ house and a boys’ house. And there were two tutors, one science and math, and one arts, humanities, and social sciences. We would spend every morning studying, and then every afternoon training for ski racing. And we would do that from October through April.

Then there was this moment where I qualified, and so we said to my school in NYC, “She needs to stay for the Junior Easterns.” And they said, “Well, she can’t.” And my parents said, “What do you mean, she can’t?” They said, “She has to come back. If she doesn't come back for prep and exam weeks, she can’t come back at all.” And we all looked at each other and said “I can’t go back. I've just qualified for the Junior Easterns. That doesn't make any sense at all!” And to my parents’ credit, they said, “She’s not coming back.” So we had this little moment of playing chicken with this whole thing. And they said, “Then don’t come back at all.” And so we said, “Okay.”

And so there was a brief moment where I was enrolled in like a public high school in Vermont. And then one of the other private girls’ schools in New York—where my sister went—reached out and said, “We’d be happy to have her come to us, and we will accommodate her schedule.” The whole thing was sort of silly. The first school kept saying, “If we let you not come back, we’d have to let everybody not come back.” And I'm thinking, “That doesn't even make sense. Not everybody has qualified for the Junior Nationals”. I was doing well in my classes. I thought, “I could understand this if there was a problem, but there isn’t a problem. There’s just your rules, is the problem.”

I first transferred to the school in Vermont, where I nominally finished tenth grade—ironically, because I never actually went there, so it was all very theoretical. Then this other school in New York said, “We will happily take you. We will work with you. We get it. As long as you're doing well in your classes, we will work with you. If you start doing badly, that’s different. But as long as you're doing well, we will work with you.” And so I transferred to this other school.

And then a strange thing happened. That school was in the middle of changing when they did physics. So in the end, I had, in 11th grade, a high school physics class, where there was only five of us in the class. These private schools, they're small anyway, but five was really small. And this physics class was taught by a woman who was getting her master’s degree from NYU. I always thought she was getting her master’s degree in physics, but I learned years later, she was actually getting her master’s degree in biology.

So she was teaching our class, and she taught this amazing physics class. Amazing in the sense that I learned nothing that one normally considers introductory physics, but we learned so much about black holes, and timelines, and waves. We learned all these amazing concepts. And I remember literally at one point figuring out, or believing that I had figured out, how the universe began. That the universe had begun with a forward-moving universe and a backward-moving anti-universe, spontaneously created out of the vacuum. And I was all excited, and I went to her and said, “I think I've figured out how the universe began.”

Zierler:

[laughs]

Hellman:

And she just let me go with that. We explored it. We talked about it. And meantime, I was also going to the school in Vermont with the tutors, and the math science tutor there was incredibly excited he had an 11th grader with all these ideas. So I basically got all this one-on-one just amazing physics. I loved it. So I went to college totally convinced that I wanted to do physics, having loved high school physics.

My senior year in high school was academically a mess. The tutoring approach became a full-time school, so it was actually an accredited school for my senior year. Which mostly resulted in my doing absolutely nothing scholastic my senior year. I ducked everything I could, and spent my time focused on ski racing. I almost didn't pass. There wasn’t much standards being set in this first year while they figured things out, but there was some. I did have to pass a chemistry test, which since I had never even opened the chemistry book, was a significant challenge. And I did have to pass it. Fortunately, they gave me three tries to pass it, and by the third time, I had figured out the answers, so that I did pass this chemistry class! So my senior year was an unusual one and not very academically focused.

Anyway, the next year I went to Dartmouth intending to be a physics major, loving physics. I just thought it was amazing. I took a placement test for physics at Dartmouth. Dartmouth is a liberal arts college, so you don’t take tons of classes in your major. But there was an advanced physics sequence, which was called Physics 18/19, and then there was the regular physics. The regular physics sequence didn't start until the winter, but Physics 18/19 started in the fall. And I knew I wanted to ski race in the winter. So I wanted to get into Physics 18/19, not because I had had any particularly advanced physics training, but because I wanted to start physics in the fall, not wait until winter. So I took this placement test.

Which was interesting, because I really had had none of the traditional physics. The person who was teaching the advanced class called me in, and he has my exam in front of him, the placement exam. And he said, “You know, I'm trying to decide what to do with this. Because you didn't do particularly well on the questions, but you seem to have a lot of insight, and I feel like you inherently know a lot. But you didn't do particularly well. So it’s on the edge, and I wanted to talk to you about what you wanted to do.” So I told him I really wanted to take Physics 18. So he said, “Okay.”

There were I think four, out of 40, which is quite a large number for those days. This is 1974. Bruce Pipes was personally responsible for a fair number of young women physicists coming out of Dartmouth. This is also the days of co-education just starting. I was the third co-ed class at Dartmouth, which was its own story, and quite horrendous in some ways, and bizarre in some ways.

I've had a few places in my career where the only reason I'm still in physics is some person like Bruce Pipes intervened and helped. He was amazing. I was in his office every week with homework problems that I didn't understand. There was so much I didn't understand. I remember one of our very first assignments was on a computer, to create an orbit of a satellite around the Earth. And I didn't even understand what this meant. I thought computers did things like solve for prime numbers. I knew that for a satellite going around the Earth, there was an equation—F=-Gm1m2/r2. That was fine. I knew that. But I didn't have any concept of what it meant to put this into a computer and make an orbit. None of this made sense to me— there was just no connection.

So there were two problems with me and intro physics. One, it was incredibly hard, because I just did not have the background. Two, it was incredibly uninteresting to me. I genuinely did not care how fast a spring oscillated. I did not care how long it took a block to slide down an incline plane. So this was a double whammy. Hard and uninteresting to me. I wanted to talk about black holes and timelines and universes moving forward and backwards and things like that. I went into his office at least four times that first quarter to tell him I was quitting, that I just didn't want to do this. It wasn’t what I pictured. And he just kept saying, “You have to hang in there. This is not what physics finally is. You have to learn all these tools. You will eventually get to where you can do the kind of physics you want to do. But you have to get through this stuff.”

And it’s a message I convey a lot to my students. Like, don’t be discouraged in the early days if it seems hard and not interesting. You will get to the place where it’s about creativity, and ideas, and not just problem sets, which are not very interesting. And by the way, getting back to the question about ski racing versus science—my whole model was fall quarter was going to be about getting school stuff done, and then winter, I was going to get back to my ski racing. And that’s what actually happened. I missed most of my classes that first winter quarter. I was gone, all the time, ski racing. And he still stuck with me, talking me into continuing, and I hung in there.

It was horrible. I mean, there was a moment when I wasn’t doing school well, and I wasn’t doing ski racing well, because they just didn't coexist very well. I could feel that I was not skiing as well as I had, and manifestly not doing as well as I had been, and also not doing a very good job with my schooling. So I stuck that out for the winter, and then decided I would quit ski racing.

And so in the end, I got to design my own thesis. For better or worse. There were times when—late in my thesis, Ted suddenly came up with completely other ideas. Once, near the end of my thesis, I was already supposed to be at my postdoc position at Bell Labs. Ted had a conversation with Phil Anderson about strong coupling superconductors, and this idea they had, instead of the electrons and the phonons and a weak interaction between them that led to superconductivity, the whole problem needed to be flipped the other way around. The interaction was the dominant thing. And so you had to recast everything, you didn't start with separate excitations and then a perturbation. You had to start with the coupling between them.

That’s exactly right. So it was a great time to be there. Mike Gyorgy was probably the best collaborator I've ever had. He was infinitely patient and willing to work complicated questions through— I would just come into his office, and we would scribble on the board. He always had time. He never said to me, “Look, I'm sorry, I can only give you half an hour.” He seemed to have as much time for me as I needed. We worked all kinds of science problems through together. He was just an amazing man.

I then applied for jobs, after my postdoc—1987 was a good time to be applying for jobs, so I applied for assistant professorships all over—I had something like 14 job offers. I had one big advantage—everybody else who was a postdoc was working in superconductivity, and I wasn’t. I was working in magnetism. [laughs] And so I stood out. It was kind of ironic. I was pretty much the only person who used to work in High-Tc superconductors. Like, I used to work in High-Tc back when they were A15s. But I think I stood out as a result. I mean, that’s not quite fair. I did a little bit of work in High-Tc while I was at Bell Labs, also.

Zierler:

Now, did you start up a lab right away? Did you have the resources to do that?

Hellman:

Yep. Kind of. The physics world was in a transition where assistant professors were starting to get more real startup packages, but they were still kinda small. So I didn't really have enough. And in particular, I didn't have enough to actually build the lab. I inherited a lab that wasn’t even empty. My lab literally was full of stuff. The first thing I had to do was get rid of all the stuff that was in my lab, keep what I wanted. Literally the first thing I had to do, was clean all the person’s stuff out of there, that had been in there before.

Somewhere in there, as an assistant professor, I wrote some grant proposals, and got enough money to put together my first deposition system. But there was no money for the electrical power and the cooling water and things like that. And I remember going to the vice chair for facilities, and he said to me, “You're asking for the wrong amount of money.” And I said, “I don’t know what you mean.” And he said, “It’s too much for the department, but it’s too little to go to the university.” At the time, there was a senior person who had just been hired who had gone massively overbudget, and they had managed to accommodate it. And I just looked at him and I said—I think I actually said something like, “This is”—well, let’s just say—"bull-pucky.”

Zierler:

[laughs]

Hellman:

Something like that. And I marched out of the office. I said, “This is ridiculous.” I was going to leave. There was no point in my staying. I couldn’t ask NSF for these infrastructure needs—I think I needed like $50,000 or $70,000 to put a new transformer in the building to power the needs of the deposition system. And NSF is not going to give you $70,000 for a transformer for the building. So I went to the department chair, which was Roger. And he just said, “We'll figure out how to do this.” And he did. I still don’t know how he did it, but he did.

Zierler:

Between the opportunity to build a lab and the fact that the resources were so slim, that really requires you to focus on what’s most important experimentally at this stage in your career. So what was it?

Hellman:

I was doing the multitasking thing. I had two priorities, for better or worse. My thesis work had involved what we called microcalorimeters, which were these little silicon and sapphire chips that we used for calorimetry on relatively thick films, but nonetheless thinner than commercial calorimeters can handle. Micron-thick films, using these little silicon and sapphire chips that then you wire-bond leads out to the side. You don’t work in an adiabatic limit. You're working in the time domain, a technique called the small delta T method specifically. You actually do the equivalent of—it’s much like an RC circuit. You put power in to a resistive heater, you reach an equilibrium, where the power flowing in through the heater is equal to the heat flowing out through conduction or radiation. And after that equilibrium is reached, you then turn off your heater, and measure the relaxation. And that relaxation time is the specific heat over the thermal conductance of the link. So much like measuring a capacitor’s capacitance, by measuring the time decay using a known resistor. You'd have to know the resister, then you would measure the time constant, and that would give you the capacitance. The small delta T calorimetry technique is much the same. You have to measure the thermal link, which, without going into all the details, is a hard thing to do, but doable. And then you measure the time decay, and that gives you the heat capacity.

I had done that in my thesis work, and so when I got to San Diego, my goal was to set up two things. One, I needed to be able to make thin films, so I needed a thin film evaporation system—you know, a high vacuum or ultra high vacuum physical vapor deposition system, multisource, things like that. And two, I was going to design the next generation of calorimeters. I looked into this, and I realized that there was a new MEMS technology that was membrane-based. People were making these amazingly strong, thin amorphous silicon nitride membranes. And you could make them pretty large, but thin, and still strong enough to stand up to being handled. People were using them for all sorts of things. They were using them for x-ray masks, for sound velocity measurements, pressure transducers. I realized I could use them for heat capacity, because the thermal conductance is so low through the membrane that I could put a sample in the middle, and the membrane would thermally isolate the sample area to allow the small delta T technique to work.

So I set out to do two things. One was to build a way of doing thin film evaporation. And the other was to design this next generation microcalorimeters, membrane-based. A calorimeter on a chip, if you will. It’s a completely self-contained calorimeter, using MEMS technology to make these membranes. And that, interestingly, involved coming to Berkeley. [laughs] I looked around, where I could make these membranes. It turned out Berkeley had what they called the Nanolab at the time. So I visited and talked with people at Berkeley, and they welcomed outside users. For the next five or six years, my research group—pretty much my students—would every summer rent an apartment in Berkeley, and they would fabricate devices.

It took us about five years to get this to work. It was very close to not happening in time for me to get tenure. That was pretty darn risky—as somebody said to me at San Diego, “You've put an awful lot of eggs in that basket.” And I said, “Well, I don’t know what else to do. That’s what I want to do. So I have to put all of my eggs in that basket.” It worked, but barely—the paper, the key paper, to getting me tenure, came out pretty much exactly when it had to come out so that I wasn’t denied tenure. [laughs]

Zierler:

Phew.

Hellman:

Yeah. It was a little interesting. It never crossed my mind not to do that. I really had this feeling that if this didn't work, so be it. “This is what I want to do, and if I can’t do it here, I'll go somewhere else, or I'll do something else. But this is what I want to do, so I'm just going to do it.”

Zierler:

Did you take on graduate students right away?

Hellman:

Yep, yep. I had two, in the early days. The first student was a person who was relatively senior. In fact, he was older than me, slightly. He had had a whole career before coming to graduate school, then had started in one group, then was leaving that group, so joined me. He did not work on the heat capacity development. He worked on getting our deposition system set up. I had another student who worked on the calorimetry, the microcals, as we called them then. So yeah, I had students pretty much right away.

I'm always cognizant of possible applications. Both my magnetism work and the work on amorphous insulators have both basic science aspects and possible applications. Let me use the example of my DOE-funded work on magnetism. DOE is quite clear that we are supposed to be doing basic science —the magnetism work is funded through the Basic Energy Sciences directorate. They're very clear that we are not supposed to be aiming at applications. We're not supposed to be thinking about can we make a better device, like for magnetic recording, in this case. Instead, we are supposed to work on the underlying fundamental principles that might be limiting the application.

The way DOE might put it is, anything that has a yes/no answer, like “Can we” is not the right question. The example they like to use is if you're working on photovoltaics, it’s not about “Can we make a more efficient photovoltaic?” The question should be, “What limits the efficiency of photovoltaics?” Do we understand what limits it? Can we address those limits? There’s nothing wrong with the work having an application; it just can’t be the immediate driving factor. And so in all my work, I pretty much think of it the same way. Like, why do we work on spin electronics? It’s likely to enable more efficient, lower energy consumption, with higher density bits. But if your goal is higher efficiency, higher density, more efficient, there’s a lot of approaches you would use. Engineers are very innovative, and they come up with lots of new approaches. So aiming at the technology is the wrong thing, in my opinion, to do, as a physicist.

I don’t really know how the engineers manage to do it, because industry changes constantly. People in industry and engineering are so creative. They find something that we call a fundamental limit, like the size of a magnetic recording bit, and then they find a way around it. And if there’s some limit, there’s some assumption that we're making that we should try to understand. One of my favorite professors of all time was Dirk Walecka at Stanford. He was an amazing teacher. Sandy Fetter, also my professor at Stanford, was also pretty amazing, but Dirk Walecka, even more so. Dirk Walecka would do some incredibly complicated derivation in field theory or in quantum mechanics, both of which I took from him. And then at the end of it he’d stop and say, “Okay, what assumptions did I make?” And as a class, we’d have to sit there and go back through and think what assumptions he had made. I love that approach. It’s not about the proof; it’s about what assumptions did you make in deriving the proof. I love that.

And so in industry, yeah, they're making advances all the time. And if you just focus on that outcome, of like a faster or more efficient computer or a higher bit density, there’s many ways to get there. So for me, that’s not the right problem to work on as a physicist. We have to work on a fundamental understanding of some phenomena that then may lead us to a better device. I like knowing about what’s going on in industry, but then I follow up by thinking about, what’s the underlying physics? How do I understand what’s going on and what’s limiting it? And underpinning all that is what assumptions are getting made. When they think they're about to reach the fundamental limit of some process, what assumptions are they assuming, and that if we got rid of that, we could open up a whole new approach?

Zierler:

This begs the question if there’s a Moore’s law for MEMS devices.

Hellman:

Mmhmm. You know, Moore’s law is such a funny one, because of course it’s not a law, at all.

Zierler:

[laughs]

Hellman:

It’s an observation. It’s a goal. Well, it’s a past observation and a future goal. But there’s no particular reason it has to be true; it’s just a goal. Everybody would like it to be true. Although, I'm not positive I even want it to be true, because I'm sick of having to buy new computers. [laughs] I’d be perfectly happy to just stick with my existing computer. I don’t need more memory. I just need my computer to keep working. But anyway, leaving that aside.

So yeah, Moore’s law is a great example. There are places you're going to hit so-called fundamental limits, where you're not going to be able to get beyond that. But in reality, there’s an assumption somewhere earlier, and somebody is going to find a way to make that assumption not right. Make the material granular, or move into the third dimension. Use light instead of electrons—various things, that you can imagine, that make your assumptions go out the window. So yeah, I'm much happier trying to understand the underlying principles of something, with the hope that it will be relevant to practical things.

Zierler:

Now it’s in the mid-1990s that your interest in amorphous and crystalline thin films really comes front and center?

Hellman:

Oddly enough, I've been working on amorphous materials for a long time, starting with my postdoc position. My postdoctoral work was on amorphous terbium-iron alloys, which were used then for magnetic storage. The very first rewriteable disks were amorphous terbium-iron type materials. I learned a lot about amorphous materials in making amorphous terbium-iron. That then evolved into an appreciation of the flexibility and power of amorphous materials. So in the 1990s—maybe even very early 1990s—I started working on amorphous silicon doped with rare Earth ions. And that actually has two interesting pieces in its history. One, it started as an undergrad project. I've always worked with undergrads. I love working with undergrads. I love working with undergrads in part because there’s so little pressure. Like I can just say, “Let’s try making this material.” And it’s just an idea, and often it’s just an idea I've had for a while but we haven't tried. But with a graduate student, you have this pressure of a thesis.

Zierler:

There’s a career. There’s funding. Right.

Hellman:

There’s funding. There’s a career. There’s a thesis. Sure, there can be negative results, but you kind of hope there isn’t, because it’s hard to get a job with negative results. So there’s lots of pressure. But with undergrads, as long as you've given them a good experience, they're happy. It doesn't have to work. Nothing has to work. You just have to give them a good experience. COVID has threatened that particular approach, because it’s hard to even give them a good experience. But in normal times, you just have to give them a good experience. They have to have tried some things, had the experience of having ideas on their own, designing an experiment. All of these things are what matter.

So, I had read about how silicon at the metal insulator transition has magnetism come into it, and it is a highly correlated electron effect. And when I say silicon, I actually mean doped crystalline silicon. But it was also known to happen in amorphous silicon. I mean, we could do a whole session on the beauty of correlated electron physics—but the whole idea, in my mind—and again, with an experimentalist lens on the metal insulator transition—is pretty remarkable. Let’s start with why does the theory of metals work? Landau Fermi liquid theory is all about the fact that by the time you're done accommodating all of the many electrons you have to accommodate—the totally identical electrons in their non-equivalent states—you have so much kinetic energy that the potential energy is kind of a perturbation. Again, that’s my hand-wavy statement about why this works. More or less true. You have 7 eV worth of kinetic energy, and the potential energy is less than that.

Then the interesting thing is, if you have fewer electrons, of course you have less kinetic energy, but you also have less potential energy. And it turns out the low electron concentration is where the potential energy dominates, and the high electron concentration is where the kinetic energy dominates. And you can see that in a sense, it’s almost the definition of metals. Metals are all about kinetic energy. Metals are all about electrons that are free to move. They release themselves from their being trapped on individual ions, and they move freely through the underlying material. So that’s a kinetic energy dominated limit.

In insulators, on the other hand, electrons pretty much stick back where they started. They may be in bonds or bands and lots of complexity around that statement, but they are, in some sense, dominated by potential energy. And, the interesting thing is at the metal insulator transition, their potential and kinetic energy are close to equal. And so it’s not surprising, any time you have energies competing with each other, then small perturbations matter a lot.

So, one of the things that happens at the metal insulator transition is the whole principle of condensed matter physics with its orbitals and wave functions break down. I don’t know if you've thought about this, but the term “orbital” is a very funny one. What happened to the word “wave function”? Why are we suddenly talking about orbitals instead of wave functions? And the answer is, because that’s the one-electron solution. So we're using the one-electron solution, and then sticking all our electrons, all our 1023 electrons, into the one-electron solutions, as though that had any meaning. It’s a crazy idea. Why do I not have to re-solve the entire problem? I interactions between the electrons; I should have to create all new wave functions. Why am I still sticking them in the original wave functions, as though the other electrons didn't matter? And the answer is just what I said before—that you do, but the kinetic energy dominates so it doesn't matter. It’s only the electrons at the very top of the Fermi surface with the most kinetic energy that matter.

Anyway, the point is, in the limit where the material is about to become an insulator, the potential energy terms matter, and what happens is, in a hand-wavy sort of way, electrons want to stay away from each other. As soon as they want to stay away from each other, then you get single occupation of states. And once you have single occupation of states, the spin is visible. Normally, you have double occupation of every state. Every state is occupied one spin up, one spin down. That’s the lowest energy state. One spin up, one spin down. No magnetism. But, near the metal insulator transition, highly correlated electron phenomena start coming in, creating what are called Coulomb gaps due to potential energy effects. And, the bottom line is electrons don’t want to be in the same state anymore. So they singly occupy states. They therefore have a magnetic moment. And that magnetic moment now can interact with other magnetic moments. Which they do. So they start having a magnetic susceptibility.

I thought that was fascinating, that something purely non-magnetic, like phosphorous-doped silicon, at the metal insulator transition, has a fairly significant magnetic susceptibility. And I was like, “That’s weird. It has this big magnetic susceptibility.” So my idea was I wanted to stick Rare Earth atoms in. The thought was, “Okay, we have this little tiny, dinky magnetic susceptibility here, but I'm going to put these big magnetic moments in, and they will couple to it, and then amazing things may happen.” That was the thought process that went into this project for this undergrad. And it turned out to be completely true. Huge effects happened. Huge. And all of this was enabled by the amorphous state. You can’t put that much Rare Earth into crystalline silicon. It’s not soluble. You end up with just a screwed-up mess of nanocrystals and segregation and stuff like that. But you can make amorphous Rare Earth doped silicon pretty homogeneously.

So that was the first time I deliberately made an amorphous material that wasn’t already a known material. The amorphous terbium and iron, people had known about for a long time. And I discovered some things about it, but it was a known material. The amorphous rare Earth silicon was the first time I deliberately made something amorphous, because I couldn't make it crystalline, and I wanted to understand how this worked. And we found all these amazing properties. And then somewhere in there, as a background [laughs] to the amorphous Rare Earth silicon materials, their heat capacities specifically, I needed to make an amorphous silicon background, with no Rare Earth in it. And that’s when we started discovering things about amorphous silicon, and the remarkable effects of how we grew it.

So, it’s interesting—I wasn’t that conscious of it, but it is true that as chair, I paid a lot of attention to our graduate student processes, and the prelims, and the quals, and all of these sorts of things. One of the things that I have been very conscious of —both as chair and now as dean—is the dropout rate. The leaky pipeline. I don’t actually like the term “leaky pipeline,” but everybody knows what I mean by it. The fact that we differentially lose women, and we differentially lose people of color is disturbing, and it’s not okay. We can rationalize all we want about how we're trying and we're not racist and things like that, but it’s not okay. So I have spent a lot of time, both as chair and as dean, trying to improve the climate —recognizing that there’s a wealth of literature that suggests that if you make a university more welcoming to everybody, you will differentially impact the non-mainstream people, meaning the women and the people of color. You will differentially impact them. So you don’t even have to single out women or people of color; you just have to be more welcoming in general.

My experience of not coming to Berkeley because of the feeling that it was unfriendly is important. I think it was unfriendly. But I think it impacts differentially—I think women are often more sensitive to that climate. That you're not as much part of the mainstream, so you're more likely to be sensitive to an unfriendly climate and decide not to go to Berkeley. I think of that as a general theme. How do we make processes more transparent? What is the qual exam? What is the prelim? How does this work? How do you find an advisor? Making things more clear and transparent is helpful to everybody, but they differentially help women and people of color and others who are not as mainstream. In my role first as chair and now as dean—I've got a few things I'm working on now, in the final two months in the office—to try and impact this.

So yes, in a sense, I do think, as chair, one of the things that I tried to do was to make it feel more friendly. I've always thought it was important, not just to the students, but for example, to the staff, and to the junior faculty. There’s an annoyingly large number of senior physicists who somehow regard themselves as better and more important than the staff. And to my eyes, that’s just not true. We have different roles. But I am not better than the staff. I'm not more important. Everybody is important. We're all working to support the research and teaching mission of the university, and we're all important in that mission.

So, I think you asked early on about one thing I did not say early on but should have—one of the things that is a high priority for me as president-elect of APS, and is very important to the current president as well, is the culture of physics. To have a culture which is more respectful of people. I think that’s the underlying word that one needs, more respectful. More respectful of differences. More respectful of where people are in their career, how much they know, how much they don’t know. But just generally, more respectful. Also, a more welcoming culture overall. And I’d say I wanted to add that to what I said way back at the beginning, because I forgot to say that. [laughs] So yeah, I do think that was important to me as chair.

Zierler:

Berkeley physics of course has a very strong legacy, and that cuts both ways. In terms of your agenda, what you wanted to do for the tone, what were some positive aspects to build on, and what were some challenges to overcome, right from the beginning?

Hellman:

At Berkeley, you mean?

Zierler:

Right.

Hellman:

Well, there were a few specific things that I took on. Berkeley physics Department does have a remarkable legacy, and I was very honored that I was asked to be its Chair, but you can’t rest on your laurels or assume that just because you are a great department, everything the department does is great. The oral prelim is probably the most dramatic example. There was a very long tradition of an oral prelim, which was very inconsistently applied, is the best way I can describe it. It was very contingent on who gave the exam. Each oral prelim was given by two faculty. It depended on who you got, what that looked like. And that inconsistency was something I found unacceptable as a chair.

There was a specific example where the inconsistency was just too much. There was a person who was about to get kicked out of grad school, having passed with one committee, and failed with the other. And somehow the average was getting taken. [laughs] And it’s like, “Why would it be the average?” If they had taken the two exams six months apart, either order would have worked. Either order—if they passed one, and they failed the other, it wouldn't matter. If you passed the first one, you'd be done; you wouldn't take the second one. If you failed the first one, but then passed the second one, you'd have passed and you'd have stayed. But somehow the fact that they did it on the same day meant we were going to kick them out, because the average of these two was below passing, as though the average of two exams meant something. [laughs] How can you have an average of some point system with no clear standard of what the points mean. I spent a lot of time talking to people about what their goals were with the oral prelim, and could we meet them in another way, and could we create something that was a little more consistent, and—well, friendly is another part of it. And ultimately, the department voted to eliminate the oral prelim.

One of the things I did when I first started as chair was a very important way to have started. When the dean asked me if I would be the chair, I said, “That’s crazy. I don’t even know everybody’s names. I mean, I just got here. I've been here less than two years, and I'm still building my lab.” Although at that point, I was actually kind of done building my lab. I asked for a week to think about it. And I went away, and I realized that was a solvable problem, not knowing everyone’s names.

Since then, I've appointed many chairs in my role as dean. I have five departments. Every three years, there’s a new chair, so I've had quite a few new chairs. And I have this conversation with them about—there’s things you may know or not know, but those are fixable things. And so the first thing I did as chair—in fact, even before I became chair—is I went and met everybody in the department. I went to their office and talked to them, each. In their office, not my office. I made the effort to reach out, and to ask them what they thought was important in the department. What was going well, what was going badly, what did they need. And that stood me very well going forward. The fact that I had reached out to ask people. There was a real lesson there for me, that people, by and large, just want to be heard. People want to know that they've been listened to. It doesn't mean you always agree with them. It doesn't mean you always do what they wanted you to do. But you've heard them, and considered what they had to say, and incorporated what you could out of what their opinion was.

Okay, well, there was a sequence. I was chair for six years, which is sort of two terms. And I felt like I needed to do that, because the first three years, you're just learning how to do things. So I chose to do a second three years, to get some stuff done. But then it was clear to me, at the end of those six years, that I had to make a choice. That my research needed attention—oddly, my research productivity was the highest in the sixth year, of any of the years, but that’s not coincidence. You're writing up the papers. In reality, the research had reached its natural conclusions. The apparent productivity was the highest, but the actual productivity was about to fall off a cliff. I was out of experiments, and I needed to shift directions. I needed to write new grant proposals, create new areas of research focus. So I stepped down at the end of six years as chair, because otherwise my research was going to be done.

And then the dean said to me, “I'm going to be stepping down in another year or so, and you are just a natural person to be the next dean.” And in a completely unpolitic moment—sometimes I talk without thinking quite hard enough—I said, “Oh my god, that is the last job on Earth I’d want.” [laughs] And I literally said that to the dean, which is not a very friendly kind of a thing to say. Like, “Yours is the last job on Earth I’d want.” But I meant it. I liked being chair, I liked having my feet grounded in the department, and I had no ambition to be an administrator.

Zierler:

It’s also discipline-specific, though. Dean is like—it’s everything.

Hellman:

It is. But it is Math and Physical Sciences, so it’s not that broad. My deanship is—it’s math, statistics, astronomy, physics, and earth and planetary science. It’s close enough—I mean, I have to a little bit wave my hands when I'm talking about math. The research they do is kind of esoteric compared to what I understand. But it’s still not infinitely far from my knowledge base. Anyway, I did not think I wanted to apply for dean. And I didn't apply. They started the dean search, and I did not apply. I had a whole sabbatical planned, like I mentioned. I was going to do a scientist in residence at the Exploratorium, and I needed to kick start some new directions in my research. But then they came to me and said, “You should apply. We need you to apply. We want you to apply.” “We think you'd make a great dean.” And I said, “Well, I'm sorry, but I've got this whole Exploratorium thing planned.” And, “I can’t do it now. But maybe in a year.” And they said, “Well, then, why don’t you just apply, and then we'll worry about that when we get there?” So they talked me into applying. And then they offered me the position. And I said, “Well, but I told you I couldn't start for a year.” So that’s when we got into the negotiation, and we compromised on six months. So that is how that came to be—yeah. [laughs]

And, you know, being the dean—the part that is facing the departments is much like when I was chair, and I love that part. I feel like I'm still supporting individual faculty and staff and students. I love Berkeley’s approach of prioritizing hiring assistant professors. I just love that approach. Sometimes I've referred to it as like the Oakland A’s. You start with raw talent, so you have to recognize the raw talent, but then your goal is to turn them into top players —you're the one who helps them launch their careers. And I love that aspect. Instead of the Harvards and the Stanfords of this world, who steal our faculty away after they've become successful! I really, really value this focus on assistant professors. So that part of my job is great, as dean. The part of my job that is rewarding —the rest of it is less good. [laughs]

Zierler:

So just to bring our narrative up to the present, back to the science, the past five years, what have been the scientific topics that have been most compelling to you?

Hellman:

Well, there has really been two, and they're both related to the amorphous materials idea. One of them is this ideal glass, and the hope that we have found a way to make an ideal glass by taking advantage of thin film growth techniques, which gives the ability to have significant atomic diffusion at the growing film surface despite being well below the glass transition temperature. The pragmatic aspect of that could be the next LIGO mirror coating. I had a high profile article in The Atlantic, which was very cool, although a bit scary, because you don’t control what writers write. I got more credit in that than I was totally comfortable having. And some of my LIGO colleagues were a little bit taken aback that I was the one interviewed—I had to send them a note saying, “I'm sorry it sounds like I thought I was doing everything, but really that isn’t what I said.” And the few of them said, “Well, you should have demanded to see the page proofs.” And then others said, “Come on, guys, you don’t get to see the page proofs.” [laughs] “That’s not the way this works. This is a news article. Lay off of her. She just interviewed, and they wrote what they wrote. And you don’t get to see page proofs; that’s not the way it works with The Atlantic.”

So, one of the things that I'm the most excited about is this ideal glass and its connection to low noise — this has potential to be the greatest overall impact in my career. I am however badly behind in writing papers, which is one of the things suffering under my overcommitment level. My students may kill me if I don’t get caught up—I have papers sitting on my desk for months, which is terrible, and very unfair to them. But I can only do what I can do. I think the idea of this ideal glass and its connection to the excess heat capacity and excess mechanical losses in amorphous materials—or to making those go away, to be exact—that the ideal glass can make those excess excitations go away—I think that’s one of the big things that is happening in my career right now.

I know. And you know, just to loop all the way back in my history to when I was an undergraduate—Dartmouth, it’s a liberal arts college, so I only had to take eight physics courses. It led to some problems when I got to grad school, by the way, that I had only taken eight physics courses. But, I got to do physics reading courses. I did two reading courses when I was an undergraduate, one on superfluid helium, and a second one on black holes. And keep in mind, this is 1977 or 1978, my senior year in college. I read this article—Cyg X-1 had just been discovered. Prior to that, everybody thought black holes were just a mathematical abstraction, that they were actually impossible. Everybody assumed there was some way around the math that led to this mathematical insanity of a singularity. But Cyg X-1 had just been discovered and was already pointing pretty strongly at being a black hole. And Kip Thorne wrote the article on which I did my reading course.

So at Dartmouth, in 1978, I did a reading course using Kip Thorne’s Physics Today article on black holes. I wrote this whole report about Cyg X-1 and black holes and Kip Thorne. And then graduate school, postdoc, and I go to UCSD as an assistant professor, and Kip Thorne is coming to give a colloquium. I read this article by him when I was an undergrad, about black holes. And now he’s coming to UCSD to give a colloquium, and I'm totally starstruck, and was like, “Oh my god, I get to meet Kip Thorne.” And I meet him! And he’s only like ten years older than me!

Hellman:

Yeah, so you can just picture him. He’s like, “I don’t care that they want me there. I'm not going to change my plans because I might win the Nobel Prize tonight.” And in fact, he didn't win it that night. It was a year later that he won it. But he was like, “I'm just not going to change my plans because I might win the Nobel Prize and the PR people want me at MIT.” He is visiting Berkeley and he has a whole set of meetings scheduled. And I'm on the meeting schedule, or maybe I'm not on the meeting schedule. I was going to introduce him later, I think because I was dean, and I wanted to make sure he knew that I was going to be introducing him, and that I was now being invited to join LIGO. And I wanted to not surprise him with that information.

Yep. And Saul, when he won the Nobel Prize, he was all expansive, and he brought literally everyone—his whole team— into the room, and he ended up sitting on the table. Everybody else had a chair, and he hopped up on the table, because somebody else had taken the chair that he was supposed to be sitting in. And you know Rai, Kip, and Barry—the first LIGO conference I went to, right after the Nobel Prize had been won. Everybody is “Rai” this and “Kip” that and “Barry” that. And this is undergraduates and technicians and staff and faculty. And everybody’s on a first-name basis. I had never experienced anything like that.

And the three of them were like, “We tried to give the Nobel Prize back, because it should have been for the team, but we realized that wasn’t really going to be helpful, to give it back, so we decided to accept it. But it really is all of yours.” And it’s just this giant love-fest. Not all of science is that way. There’s a lot of very competitive science out there, where everybody’s not all chatty and happy and passing credit off to everyone else. So it was a real delight to get to join the LIGO folks.

Zierler:

Frances, for the last part of our talk, I’d like to ask two broadly retrospective questions, then we'll end looking to the future. So the two questions – we'll do one on the science side, and one on the sociology side. So we'll start on the science side. Amorphous materials has been the through-line for you, really from Stanford all the way to now. What is your fundamental curiosity that keeps you so connected, and what remains unknown that keeps the field productive, and there’s always the need to do new stuff?

Hellman:

So, I have a two-part answer to that. One is that amorphous materials are very underexplored compared to crystalline materials. There’s a richness and an availability. I can make materials that nobody has ever made before. Sometimes, like my example of amorphous gadolinium-silicon, there is no crystalline analog. You simply cannot make Rare Earth doped crystalline Si with enough Rare Earth in it to be interesting—and the Rare Earths are the only ones that have this giant magnetic moment. There is no crystalline counterpart. And so making it amorphous has opened up a whole set of materials that have never been made before, with all new possible properties, and that’s exciting. It’s a very unexplored area.

So that’s half of it. It’s a much more wide-open field. Very few people like working in amorphous materials. Because it’s harder to do structural characterization. If you have a crystalline material, you can characterize the degree of crystallinity. The only thing I can do is try to characterize the entropy/enthalpy, and that involves pretty high-temperature thermodynamic measurement. It’s harder to directly characterize the materials. So, one motivation is just, it’s a wide-open field. And I like working in wide-open fields. I like having parameter space to explore, where I'm not directly competing with anyone else. I get to go try things and see what works. So that’s part of an answer. The other part is—it’s maybe even a little bit mischievous. I like the fact that the theorists don’t like amorphous. I mean, really, literally, theorists say this to me all the time.

Zierler:

[laughs]

I have half-written papers sitting on my desk with data that I don’t yet have a model for. I don’t just crank out papers. Most of my papers are unique. I have very few multi publications on the same idea. Very, very few. I tend to wait until I really have something thought through. Right now, we are sitting on a really huge result. I've talked about it at conferences, but I've not published it, because we don’t understand it. And I'm very conflicted as to whether I'm just going to go ahead and publish the data, with whatever understanding we have right now, and just let it be, or am I going to keep trying to find an answer to why the data is the way it is. And I don’t know the answer to that yet.

So, how will I know? How will I know? I'm very excited by the ideas we've already got! We have to get them out into the literature. I'm frustrated at my own inability to get these things done.

Zierler:

Well, on that note, Frances, let me let you go and get back to the papers. It has been so fun spending this time with you. It’s a great example of why what I do is really not work at all, which is why I'm so happy to do this on a Sunday evening with you. Thank you so much for doing this. I really appreciate it.

Hellman:

Thank you. It was lovely getting to meet you.