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Interview of Philip W. Anderson by P. Coleman, P. Chandra and S. Sondhi on 2002 May 29,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
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Anderson discusses his interest in Complexity and Physics of Information; the Santa Fe Institute; his doubts about DCS theory of superconductivity and theory of A15s; resonation valence bond ideas; political involvement from local issues to Star Wars defense. Other topics include: ferromagnetism; Ginzburg-Landau theory; Josephson effect; magnetism; military research in the United States; solid state physics; solid state physics in Japan; spin glasses; superconductivity; and spin lattice relaxation.
So we are gathered here today the 29th of May 2002 for the sixth and final of our series of interviews with Phil Anderson on his career in Physics and also his involvement in activities outside of Physics. With me, as usual, is Piers Coleman, Premi Chandra, and I’m Shivaji Sondhi. And I will now turn the floor over to Piers for continuing our discussion.
Phil, good morning. One of the trends we wanted to pick up today was your growing interest in aspects of complexity that began I suppose in the early ‘80s. We would like to ask you about that and I suppose to kick things off I wanted to ask you about your work that led up to your paper on “A Suggested Model for Pre-Biotic Evolution and the Use of Chaos” that you published in ‘83?
Actually my general interest in this field started quite a bit earlier. I think I talked perhaps during the Nobel Prize discussion of the fact that in the middle of all the Nobel fuss I had a call from a man named Eugene Yates who was interested in general biological theory. He’s not a terribly important figure scientifically (I hope he doesn’t hear me say that), but he runs journals. He runs a neurophysiology journal and writes editorials which are interesting. He was running a session of the big neurophysiology meeting at Keystone in Colorado and he asked me to speak. After saying, “Oh it’s nice you are still alive,” he said why don’t you come and join this session. I joined his session with three fairly interesting people: Gene himself, Arthur Iberall, who was kind of a wild old Marxist who had always believed that he has the theory of life, and that it’s the physics of life he insists on talking about — the physics of society and the physics of life — and he has a very Marxist view that everything is “science”. On the other hand, he has many good ideas and he was enormously knowledgeable about biology. So I spent a lot of my time at Keystone walking around on the hiking trails with Ibby learning about all the kinds of things I hadn’t had the faintest idea of: that Biology contained like non-coding DNA and microtubules and so on. I was fascinated by the idea that the cell itself had a skeleton. Then the other was Arnie Mandell, and he is notable for being the guy who turned on the San Diego Chargers football team. He was consulted if somehow could he inspire the football team, and he chose to do it chemically; later on for some reason he won a MacArthur Prize. He did write some very interesting books about altered states of consciousness. But I didn’t learn so much from him, I did learn a lot from Gene and Ibby. I had a good time and I think that was the last time I ever had a pair of racing skates on, for instance, in Keystone. The second thing that happened in the late ‘70s was the Solvay Congress, and being a colleague of Prigogine, naturally I was invited to the next Solvay Congress, which was a very plushy event in Brussels. I chose to talk at that one about what I didn’t believe about Prigogine’s own work. I totally disbelieved his theory that he gave in his Nobel Prize lecture, which I think is now discredited completely, but which had to do with variational properties of entropy production, and it turns out that that is not what determines non-equilibrium structures. He had this idea of dissipative structures, and his favorite example is Benard cells, there was the Brussels School and they did many interesting things. They studied the Zhabotinsky reaction, the thing that makes spirals, they study pattern formation, and he was an eminent figure in something called the Institut de la Vie which met once a year in a French Chateau, again very plushy — if it’s Prigogine, then it’s plushy. Also some respectable people were involved with that like Don Glaser. But they would get together and talk over all these problems of complexity, the origin of life, et cetera. But I kind of had a jaundiced view of the Institut, I think I was invited once and said no. But at that Solvay Congress, two things which were important to me happened, one was that I was sitting around the pool in the Solvay Mansion, which is lined with marble and drinking very expensive burgundy, and right next to me on one side was Yu Lu and on the other side was Hao Bang, the two Chinese who had just escaped from the Great Cultural Revolution. And Yu Lu turned to me and he said, “You know, one year ago I was living in a pigsty, and here I am drinking this marvelous wine at a marble-lined pool.” And the other was that I gave this talk which was my introduction really to non-linear mechanics and pattern formation and so on. It was a fairly naive talk but I don’t think there was anything about it that is absolutely wrong. I stuck my neck out and said something. Then from Keystone came Dubrovnik. Eugene Yates ran a big meeting called Self-Organization in Biology, a big meeting of the developmental biology world.
When was this exactly?
That was in 1980 and Dubrovnik was still intact; the Serbs hadn’t gotten at it. It was an absolutely idyllic place to be, except that the meeting room was awful. It was suffused with afternoon sunlight and totally stuffy. But nonetheless we sat there and we listened to each other, and I met some very respectable molecular biologists. Gunther Stent, for instance. In molecular biology Steve Gould gave a talk, Harold Morowski gave a talk, and so on. So I began to meet this community and learn something about biology. Gene Yates gave kind of a non-stop talk summarizing the most recent results in molecular biology, which was to me very exciting; I’m sure it was just a pedagogical talk, but I enjoyed it. There and in Oxford when I gave the Cherwell-Simon lectures I talked again about dissipative structures, but I also talked about the beginning of this work with Dan Stein about early evolution. I had that idea twelve years before but never put it in writing, the idea of periodic denaturation-renaturation of the RNA. I now realize it’s an incredibly naive picture, but it’s no more naive than what most of the people were doing then or later. It turns out that actually I was, although I didn’t realize it, I was parroting what Hans Kuhn was talking about at the same time he’d had a very similar idea. And so I got connected with this group, and then finally I got connected with John Hopfield and Carver Mead and Dick Feynman who were running this course on the Physics of Information in Caltech when I took a Fairchild that year, and I had just time to get introduced to it and then came down with cancer but actually the cancer was taken care of fairly quickly so I had time to talk with Feynman and with John and Carver a great deal. That was when John had used the spin glass technique for a model of the brain, and that got me to thinking about spin glasses in these complexity problems. So that was the genesis of this June 1983 paper in PNAS, which takes a spin glass Hamiltonian as the evolutionary landscape because a spin glass Hamiltonian is what makes sense. You have a genome, which is a binary string essentially, and each site on the genome you can think of it as a spin and the interaction between different sites is certainly random and certainly frustrated — it’s non-random, but it has nothing to do with the actual sequence, so in terms of what the genetic sequence is, it appears to be a random thing. And of course it’s frustrated on every level; all evolutionary problems are frustrated problems. So out of that visit that was a fairly interesting idea to come, and I produced that paper with Dan. The reason it was so slow to come out was we needed one more thing. Dan’s computer skills hadn’t really evolved, he was too old to be really good with a computer, and so we found Dan Rokshar who was an undergraduate at the time and Danny really did the computing for us, and we got some quite interesting outcomes from just computing this model; you know, “wouldn’t it be nice if it was this way” type results. We happen to have a name for them in Santa For example: resemblance physics or resemblance science — doesn’t this resemble the real results; it doesn’t prove anything, but it is an interesting thing to do. I should have used the term resemblance science for Steven Wolframs book [laughs]. That is one of the things that is wrong with it. Some other things. There was an Aspen meeting on the Physics of Information which was organized I think by John, and somebody else at Aspen.
Which summer was that?
I think is was summer around then ‘80 or ‘81 and he had the whole Physics of Information world there: he had Tom Toffoli he had Danny Hillis briefly, Fredkin visited us; and at the same time he had a lot of people from the Origin of Life world: he had Hans Kuhn himself, Eigen dropped by; and of course there was Charley Bennett and Wojciech Zurek. So I got to know a lot of these people and a lot of that community and get a good assessment of that community through the interactions that we had at that meeting. Two things were extremely notable that had nothing to do with the sessions. Number one was rafting down the Roaring Fork with Hans Kuhn and John Hopfield and Charley Bennett. It was quite a combination. But John is a remarkable oarsman, and we all arrived more or less intact, with Hans Kuhn sitting in the front and taking the splashes, he insisted on doing that because he was very honored to be coming to the meeting and to be talking with John Hopfield and myself. He’s ten years older than I am. The other was a long walk I had with Charley Bennett and Wojciech Zurek. We went up to Conundrum and beyond Hot Springs, which if you remember is nine miles to the Hot Springs and we went a mile beyond. Charley being his highly organized self was carrying on his back a primus stove and at the very top we put a little pot on the prima stove and we had boiled I think they were Polish Sausage. What are they called? Zurek provided the sausage and Charley the stove. Also at the springs there was a very pretty girl with a kind of ski bum guy. Of course in Conundrum you have the Hot Springs, and she took one look at Zurek and that ski bum was gone, was absent.
Was that after the sausages or after Zurek himself?
Zurek himself — Zurek is a big very handsome bearded Pole, very male. But we had also talked a lot about science on the way up and on the way down. I twisted my ankle so the way down was a little slower. I have never walked nine miles with a twisted ankle before, or since, thank God. That meeting got me interested in these complex things. And then finally there was the Werner Erhard Meetings, EST — Erhard Sensitivity Training. He got interested in physics, through kind of the Tao of Physics.
Weren’t those the meetings where you had to sit in a room and you weren’t allowed to go to the bathroom?
Yeah, that’s right. And we had these zombies that drove us to the meeting, and they had to take exactly the right route, and then they were going around dusting the place and they had to dust it in exactly the right way. He had his zombie trainees taking care of us. I think we were allowed to go to the bathroom; he was a reasonable man. I do remember this beautiful Bosendorfer piano with which we were serenaded with ragtime by Alan Luther in the middle of that meeting. No it wasn’t that meeting. I went to two Erhard meetings; it was another Erhard meeting. But the first meeting was pretty wild because again this whole offbeat community was there. That’s where I met Stuart Kauffman for instance. But Norman Packard was there, and that was where I first heard about this result that there was complexity between the chaotic automaton and a non-chaotic automaton. He was talking about that. In the end it was a joint paper with Steven Wolfram. You won’t hear it from the book, but it was Norman Packard’s basic idea. So there were several other people I later got to know at Santa Fe for example. I don’t think I have the program of that meeting. But it was fun to talk in this vague way about all of these interesting ideas, and I talked particularly about spin glasses as an evolutionary landscape model. Then in the course of time we Dan Stein and I (Dan Rokshar unfortunately graduated), we had a model for the origin of genetic information, which was supposed to be a model for interaction between genes and protons, and that in essence is a very primitive version of Stu Kauffman’s Dancing Landscapes idea in evolutionary biology in general. We had the idea that we would have a collection of spin glasses and we would let them interact and change each other’s Hamiltonians as they evolved. Incidentally, the Aspen meeting; Stu wasn’t there but Weisbuch was there, and he already had an early version of what later became Stu Kauffman’s NK model for chemical evolution or for biological early evolution. Instead of using spin glasses he was using collections of random boolean networks, which is very much the NK model of Kauffman. The NK model is preferable to what we were doing but it can in principle be completely reproduced with spin glasses. But at that time spin glasses with p interactions — spin glasses with more than two spins interacting at a time — hadn’t really surfaced and I think a much better model is the NK model. It allows modulation of the degree of complexity. The spin glass isn’t yet quite frustrated enough; you really need something a little more frustrated, and the three-spin glass is probably better just as it is for glasses. So all of these lines had kind of gotten me acclimated to the complexity world, and as a result I got myself invited, or David Pines invited me, almost as a matter of course, to the early workshops that formed the Santa Fe Institute. I of course wasn’t a Santa Fe type, I was an Aspen type, but there was definitely a Santa Fe Aspen axis which involved Gell-Mann, Pines, a number of other people. I think George Stranahan threw one of the early meetings in his house in his Ranch near Aspen. Oh, and Bob Adams has a ranch in the next valley up and he was involved in the early thinking about the Santa Fe Institute, was on the steering committee for a long time. So I sneaked in as an interloper in the Santa Fe world, but I was among the speakers in what is now a book by David Pines that contains the founding talks of the workshops. These were held in successive years ‘84 and ’85, and sometime in 1984 George Cowan founded the Santa Fe Institute — it was at that time called the Rio Grande Institute, but he founded it by the simple exercise of opening a bank account. He was a banker. He owns the Los Alamos Bank, which is helpful because no one asked him who he was opening this bank account for. I believe he even put some of his own money in it because he is quite a rich man. But he had a bank account, and we then ask for money for other people to put into this bank account so we could run workshops. I think George Cowan was the explicit founder of Santa Fe Institute, the person who actually did it. And there were a number of other people around who were very important, Mike Simmons, David Pines, Peter Carruthers. At the early workshop there was a problem because Peter was in the course of falling into alcoholism, and his wife disappeared and was driving off into the desert. It was a bit disorderly for a while there.
Can you tell us a little bit about the philosophy of the Santa Fe Institute?
There is an article by Murray that is very good about it. The original philosophy was let’s look at we need an institute that looks at the spaces between fields. It was supposed to be interdisciplinary, and I think we were first on the ground there. People have now founded this fancy institute at Harvard/MIT, and even this University has five or six interdisciplinary institutes, but we were the first one to say look, what’s really important happens in the spaces between disciplines. So we were looking at the spaces between disciplines and we found work that could be classified as complexity work, but at the same time we were going to look at physics and math, but that quickly got taken over by the string theorists. We did look for four or five years at the measurement theory — philosophy of physics interface, and I think there were very important influential workshops, which unfortunately they always had in April so I never got to go to them. But this is where the Zurek-Gellman-Hartle philosophy of that problem got knocked together. But in the end, most of the really interesting things turned out to be interdisciplinary and complex, particularly as we later came to realize that’s where you can get the social sciences hooked up to the biological sciences hooked up to the physical sciences in an adequate way. So we began looking at things like that, but these workshops were just every man for himself. Somewhere in this list is my piece on spin glasses. I gave continuing spin glass talks; you will find the total file somewhere of spin glass talks starting out from pre Edwards- Anderson, then Edwards-Anderson, then pre-TAP, then TAP, and so on and then finally I began to connect TAP to things like simulated annealing and so on.
What is your sense that the impact that thinking from Physics had on the biological community, if any at that, this is out of the interdisciplinary staff meeting?
Not much, not much. Well, yes, we worked hard at getting the network point of view through, but there are good biologist who also have a network point of view. Particularly Alan Perelson and the guys working on, I forget — Avidan-Neumann, people working on the theory of immunological systems. That was the most useful application. The other AIDS application is basically in evolutionary theory and the simultaneous study of ecology and evolution. Recently they have been doing a lot about scaling; I don’t know how important that is. Yes there are real biological applications but the trouble is biology is such a giant subject and has such incredible funding and incredible personnel and very bright people that you don’t steal a march on the biologists very well unless you take a direction quite orthogonal to theirs, and then they tend to look down their noses at you. To continue with Santa Fe Institute, I was at those early things and I became a member. At first we just called it a family, a group of people, and each of these people had what we called a tool kit. There was Doyne Farmer with a non-linear dynamics tool kit; there was John Holland with a genetic algorithm tool kit; I had spin glasses. I don’t remember, there were two or three others who basically had a tool kit, and they said well this is an interesting way to go at truly complex or interdisciplinary problems. And somehow Carl Kaysen got in touch with us, or maybe he was even a member of our original group. He was on the board of Directors of Citicorp. He was a friend of John Reed’s, John Reed had Kaysen on his board of directors. Kaysen is an ex-head of the Institute, and in our early talks and discussions Kaysen was very useful because he said, “For God sake, don’t be like the Institute!” (IAS, Institute of Advanced Study). He explained to us what was wrong with the Institute. I’m not sure you would be interested in that, but we took it to heart. In particular we absolutely fought, fought, fought against developing separate non-communicating schools. We hope we’re still a unit, although the economists have more and more cut themselves off from us. But in general we are not schools; we all talk to everyone and all evaluate everyone. Well anyhow, Kaysen got John Reed. John Reed had a couple of tame economists and asked these economists what about economic models whether any of the economic models had developed a theory of the last two crises in the financial world. The crisis we had right then was the crisis of third-world indebtedness which God knows John Reed and Citicorp had been — no, actually Walter Wriston had been Citicorp’s guilty person in the development of the third-world indebtedness problem. And so he said could any of you have predicted this sudden deflation, the sudden increase in third world indebtedness. How much, suddenly, we are ruining all the third world, and they said no, of course all model methods in economics turn out to be linear extrapolations. You ask what’s in the pipeline now and you say tomorrow that someone will have sold so and so much of the pipeline. It’s worse than that, it’s really worse even than linear extrapolations. It’s really, really, really stupid. And so he said I want to come and have a short meeting with your guys and see if I think that some completely different point of view could be of some use to economics. So in 1956 he flew out to a fancy resort near Santa Fe with Carl Kaysen, and Joyce and I hitchhiked in his corporate jet. We had about a day and a half meeting in which John Reed gave the main talk and then there was Eugenia Singer who’s right here. I haven’t seen her lately but she’s a Princetonian. She was his other economist, and the other members of the group were a whole gang of people with tool kits. We had one real economist and we kind of dropped him out of the discussions right off the bat because he was so obviously stupid. Carl Kaysen is not a stupid economist; this guy was really stupid (I’ll let him be nameless). So we decided we would start an economics program at the Institute, and I was nominated because I had been to courses on economics at Cambridge and because I knew maybe two economists — I knew Galbraith [J.K.] and from high school I knew Jim Tobin, and I knew a number of other people. So I called Jim Tobin, and Jim Tobin said the guy you want to talk to is Ken Arrow, and I called Ken Arrow and he was interested. I was at Santa Barbara for some reason. I drove up to San Francisco with Joyce, staying along the Big Sur Coast, and Ken and I spent a day and he said, “I’ll find ten interesting economists if you will find ten interesting physical scientists.” And we put it together and it worked, oddly enough, in ’87 it really worked. What is now called econophysics was one of the outcomes of that, but there were also a number of other new strains in economics that we discussed: the formation of patterns, why it is that Silicon Valley was formed, and so on. That core of economists turned out be, one of them was Larry Summers incidentally, and they have become professors, not the professors but professors in the various major institutions of economics, and really, really important economists visited on a regular basis. It’s kind of a disorganization. We’d get together and project a few leaders for the program for the next few years, and sometimes they’d come and sometimes they don’t, and they invite their friends, but their friends they just love to come to Santa Fe and talk economics for a few months. So it’s a very viable program. The trouble is it’s too strong and it has a tendency to live by itself off in one corner of the building while the rest of us are talking about other science. But of all the things, the only thing that I ever institutionally founded and I’m really proud of is that program.
Maybe this would be a good point to turn to a new topic.
So let’s actually turn back to the topic of superconductivity and in particular I believe it was in the ‘80s where you and Clare Yu looked at the problem of the A15s. Could you tell us a little bit about that please?
This all started with something I found in one of my old diaries, not for this purpose but because I was cleaning out files. I noticed that one week after the announcement of the Nobel Prize there was a meeting of the Little Dirty Seminar, which is something that John Rowell ran at Bell Labs, and Bob Dynes, John Rowell, a couple of theorists (C. Varma) were members of this Little Dirty Seminar. He would get together every once in a while and talk about the impure and boring aspects of superconductivity, in particular, or anything on the puzzling transport measurements on very dirty samples or on unusual samples. And we kept looking at the saturation phenomenon for instance in resistivity and in the A15s. We kept looking at the A15s in general, you know, is this really possible quite to get Tc out of BCS for the A15s and for the relatively high Tc transition metals themselves. So I kept a kind of interest in this problem. I never actually solved saturation, and of course one sees that saturation occurred at the Mott Limit and you can kind of invent an arm waving theory for it, but I never got to work in it and wrote down a real theory for it. But it’s very striking that the A15s and similar dirty transition metals superconductors don’t have resistivity curves which are anything like resistivity of as a function of temperature of an ordinary superconducting metal like lead or mercury. Clare Yu had graduated to the graduate school, and I assigned her to think about what would happen if we really had a strong coupling situation in which the adiabatic theory didn’t work for the phonons. In other words, supposing we had the equivalent of preformed pairs — interactions which were strong enough that the adiabatic approximation was no longer valid. And she did valiant work on that, but I would be the last person to claim that it really got anywhere. I feel a little guilty about Clare, that she didn’t solve a problem. She did a wonderful job of compiling all of the data and showing that it was anomalous on the A15s in particular but also other strong coupling superconductors. Then she produced this theory that you could force-fit the data with, but it probably isn’t the theory, and that theory was kind of a space-time model of the interactions; we assumed that the interactions were so strong as to completely bias the state. In other words, quite strong coupling rather than weak coupling. So I had this series of lectures to give at Varenna that year, and I chose to do a thorough-going review paper of all that data that came from the Little Dirty Seminar; then in the end to summarize Clare’s thesis. You will find that I was very tentative about Clare’s thesis — I said if you want to do it, this is the way it works out. But that just represented an ongoing interest and an increasing doubt as to whether the BCS theory alone really told you all about superconductivity. So this is, I guess, a monument to the fact that I didn’t believe BCS, and that at the same time Bernd Matthias was rapidly coming to the conclusion that BCS was correct and therefore he was very bored with the subject. So this is just a monument to my distrust of superconductivity theories in general. In the Little Dirty Seminar we also had barium bismuth oxide, although nobody had yet found barium potassium bismuth; we had barium lead bismuth which is an anomaly with superconductivity right near the metal insulator transition. We were very interested in the Chevrel compounds because as it later turns out, probably they are the original cluster compounds, the original Buckyball type compounds, and probably whatever goes on in Buckyballs is also going on in the Chevrels. So I became familiar with all of this data, but at this point I was the data compiler only. At the same time I became very interested in heavy electron superconductivity, just more or less a watching brief. I was fairly convinced, and I think I fortunately may even have said it at one point or another in this bibliography, that heavy electron superconductors were almost certainly not S wave superconductors, and now I believe, you know, after 15 years I actually was willing to give a talk and put this in writing that the heavy electrons are all non-BCS; they are all higher orbital angular momentum superconductors. And we were doing some other things with Kondo heavy Fermion ion lattices, as you remarked last time, and this is about the point where I was developing the large N model and you were doing your thesis on Kondo resonances, and I think finally the final paper of that sequence is the paper I gave at Bangalore. Is it here?
Doesn’t seem to be there. It was in ‘87.
It was in ‘87. Well it was given in ‘86, wasn’t it, or was it just?
No, it would have been January ‘87. [Searches for paper]
Oh yes, that’s it, that it. And I think I was saying in words in that talk what I never had that gumption to do in reality, which was to say in other words what one needed to do was to invent the dynamic mean field theory for this problem, DMFT, because I was saying the key thing about these things is that the self-energy is strictly a function of frequency and not of space. And I was saying already at that time that the self-energy is strictly a function of omega, and looking back really to the old Clogston-Anderson papers which said really what’s happening in the magnetic impurity is all happening on-site. There’s some Friedel oscillations; they’re kind of irrelevant. What’s really important is all happening on-site as a function of frequency. What you should really think about is a time history of the magnetic moment on-site, and the background metal can be either real metal or it can be the f electrons. But the background metal is not really contributing an important space-like component to the self-interactions of the spin. This, of course, is really arguing against Philippe Nozieres who always had this exhaustion model. The exhaustion model is equivalent to the old stuff that there is a compensation cloud for the Kondo problem. But there is not a compensation cloud, it all happens on-site; there is merely an interference phenomenon that takes place and causes Friedel like oscillations. So I had the music for the dynamical mean field theory but I didn’t have the words, and I was trying in a very clumsy way to say it in this talk.
Since we are already in Bangalore with the venue of your talk on mixed valance, this is perhaps as good a point to make what was in fact chronologically also a dramatic entry of the entire field and especially you into the problem of high temperate superconductivity. Perhaps you could take us back to when you first heard about the news and how you reacted to it.
Well, actually Ted Geballe had said a little something earlier, and he said there is this Mueller paper, and maybe it’s right, maybe it’s wrong. Then Ted went to the famous materials research society meeting in December in Boston, and he said, “Look, it’s right, and what the heck is going on with high Tc with these superconductors?” You know nowadays when we look back on it, 35 degrees, what kind of sloppy transition, how could it be really exciting? But it’s hard to think yourself back. We’d been frustrated at 23.2 degrees for 15 years, 20 years, and suddenly here was 35 and it was in a very unlikely kind of superconductor. I think we were right to be excited and Ted was right to be excited. So he said you had better believe this and it’s the Japanese and the Japanese are usually right. So I began thinking about it. I got the crystal structure out of Ted and eventually I worked out in maybe a couple of days that it was a very good structure for a Mott insulator. Certainly in putting in the dimensions that Ted had worked out, the copper was strongly Jahn-Teller split; as a result the last remaining hole band was non-degenerate so you had your good example of a one band Hubbard Model. That may have been the last absolutely right thing I did in this field. It excited me. Then during the meeting, I happened to hear Maurice Rice talk about the one-dimensional Hubbard Model, where he had been redoing numerical calculations which I guess Peter Horsch had done earlier and he showed in his talk how almost exactly the one-dimensional Hubbard Model many-body ground state was reproduced by a simple Gutzwiller projection of a half-filled Fermi sea. That fascinated me, and I thought, supposing we do a projection of a half-filled Fermi sea for a metal, and then I realized there was this old Dyson construction with another step essentially turns half-filled Fermi sea into a superconducting ground state, a BSC superconducting ground state with a cosine K gap, and then if you Gutzwiller project it, you could get something which would resemble the resonating valance bond ground state that Patrick Fazekas and I had been talking about in the past. And so I was very excited, I thought gee this is it; you just take this Gutzwiller projected BCS for the half- filled case and somehow you dope it and displace the Fermi surface so you make free particles, and the result will be a superconductor, which seemed easy like falling off a log. So I gave them a little talk at the end of that meeting presenting these ideas and went home. I went home actually to Caltech because I had decided to take the second half of my Fairchild during the fall semester in Caltech. Joyce met me and we had a much more pleasant house this time in Caltech than the previous one, which had been a ground floor flat and not ideal. This was beautiful, this was right on the boundary of San Marino, and “Dynasty” was being filmed in the house right behind us, which just indicates the quality of the housing in that general area. And we had a grapefruit tree in our front lawn, so we had grapefruit every morning. So we had a very pleasant time in there and I was in a state of euphoria, and I wrote this paper for Science. And then I got into contact with Baskaran who was back at Bell Labs, and said you have a problem. If your state condenses at J and J is a thousand degrees Kelvin, how do you get Tc down? And I think it was his idea first, but between the two of us we worked out the idea that maybe because there is very little charge in the excitations the phase stiffness will go down, the phase stiffness should reduce linearly as you go down to zero doping. And he was busy writing and I was busy writing. First it was my Science paper which I more or less had the original idea plus some kind of vague hand-waving at the possibility of making a superconductor out of it. Then with Baskaran, I wrote this paper in which we had the idea that the phase stiffness went down and so you could expect Tc to go zero as you went. Actually at the moment I think all of that was correct in essence; I think we really had a correct, not even totally hand waving picture of high Tc. The trouble is then we began to modify it and modify it and try to make things go better and better, and every time we modified it a little, it got worse and less in correspondence with everything. I don’t want to go into that history here, but it ended up being one great big mess, and it was 1995 before I got back out of all red herrings and began to believe that in essence we had been right in the first place, if we had just stuck by our guns. Of course there is a lot of other stuff. One thing that we were not right about in the first place was supplied by Ian Affleck and Gabi Kotliar. Ian Affleck I think was the first one I think to say how do you know it’s cosign ksubx, plus cosign ksuby why isn’t it cosign ksubx minus cosign ksuby which gives you a D-wave gap rather than an S-wave gap. Gabi I think was the first person to do the numbers and show that thing had probably got a lower energy than the S-wave gap. Sometime during I think the Berkeley meeting — we were going to meetings kind of continuously for that first year — and so I was meeting everybody and we were all talking about it and then arguing about it, and I had a long knock down drag out argument with Bob Laughlin, and Bob didn’t say D-wave gap, he said it’s actually the Gutzwiller projection of a pi flux phase that had a gap like the D-wave system. I said, okay you stick to your D-wave gap, I’ll stick to the S-wave gap, and we’ll both follow-up the problem and see what happens. That was a very bad mistake on my part because D-wave gaps, by the end of 1994, turned out to be what you have. So I was busy trying to find a way in which an S-wave gap could possibly make a superconductor, and I fastened on the idea of interlayer tunneling theory, and that was the big red herring that I fell into over this long period. The problem which always and still worries me was why is the superconductivity so independent of impurities? Why can we make a dirty sample in your kitchen stove and have it have the same Tc as a perfect crystal. And that’s still very strange. It still isn’t obvious why that is the case, but that was why I stuck for so long with this incorrect idea of S-wave gap.
It’s almost as if your greater familiarity with isotropic superconductivity in the past put you in an awkward position making too much of an expert at the present.
Yes, I was too much of an expert, knew too much. And I didn’t like the D-wave gap because I thought that would be impurity sensitive. You know, I didn’t really believe my own insight that all the heavy electrons were D-wave, which was I think true. Not D-wave, but anisotropic.
There is a second theme that you pursued after the initial ideas which I would like to bring up just to see what way you’ve taken in, which is this idea that you wanted to find a two dimensional non-Fermi liquid.
Yes, I’m still ambiguous about that. Everyone tells me I’m wrong.
Well let me ask the first question, which is starting with the RVB state, in a sense you already had a description if not a mathematical theory of a non-Fermi liquid state. What led you to want to generalize this idea, in particular during much of this period I think you were very strongly focused on optimal doping behavior. Whereas in the initial RVB physics optimal doping was in fact just a point where two different lines crossed. It was a cross over agent. So what was the motivation for going down this road?
Partially because as I looked at the data, the data looked like they scaled nicely, and they were very simple for optimal doping. Of course linear resistivity is another difficulty with conventional theory. It had this nice scaling linear resistivity. It had various other nice scaling properties. You could understand various kinds of properties with a composite carrier theory. And I became enamored with my theory of the Hall Effect because the temperature dependent Hall Effect is the most difficult problem in that area. The Hall Effect again scales very nicely; it definitely gives you a T2. Almost everything scales very nicely for the optimum doping, and so it looked like the optimum doping was some kind of ideal state, you should try to do a theory of it. And it seemed like the theory was going to be the Luttinger Liquid Theory that I worked on and wrote many papers about. I discovered this difficulty of ordinary theory at our workshop in Cargese; we had a RVB workshop in Cargese. I was determined that we were going to get the theory done and right before we were going to publish the workshop in Cargese. That’s one of the dumbest things I ever did; I should have published those papers that were given at Cargese because many of them were very important to the field and got published in the end. Some of them were flux phase papers and some of them were this and some of them were that, and I said no I don’t want to publish a book with all of this controversial inconsistent stuff. That was dumb because in fact that was the correct assessment of the state of the field at that time, and several of the papers, particularly Xiao-Gang Wen’s, were first-rate papers. But I did see the fact that the conventional theory of the two-dimensional Fermi sea was incorrect. Whether or not the correct theory is the Luttinger Liquid or something else I don’t know yet, but the conventional theory is incorrect; I have no question about that. Nobody has given the correct theory of the two- dimensional Fermi gas, the problem being that there is undoubtedly this anomaly of finite phase shift at Q equals zero, and that’s correct. The point is that maybe it doesn’t cause failure of the Fermi liquid theory. That’s still a hard problem to solve. I don’t trust any of the various people who claim to have solved it.
Let me ask a different question. As you know, a lot of fairly recent experimental work when there is some evidence that over portions of the cuprate phase diagram you have coexisting orders of superconductivity with perhaps a charge density wave and a spin density wave. So one of the questions that sort of comes out of it is whether I think one of your recent contributions on praising unstable fixed points perhaps has some bearing on this which is whether for a strongly correlated system — you can have multiple computing instabilities in which case would the task of theory, is it really possible to predict them at asymptotically low temperatures?
Hard, but not necessarily impossible, of course. We look at the heavy electrons and undoubtedly this is happening, we have coexisting superconductivity and anti-ferromagnetism. We have all kinds of animals, vegetables, minerals, and mugwumps in the heavy electron system, and why shouldn’t there be animals, vegetables, minerals and mugwumps in the cuprate system? You can see that there will be inhomogeneity for sure as you start to dope it because of long range coulomb effects. In the paper I never somehow managed to get on the web about stripe phases, you can see that in fact D-wave superconductivity is favorable for anti-ferromagnetism rather than the other way around — it increases the susceptibility for anti-ferromagnetism, not decreases it. So unlike S-wave superconductivity and ferromagnetism, which have contrasting requirements on the long-wave length susceptibility, the short wave length susceptibility for a D-wave is favorable, and you can have a reinforcement effect. That’s what Brinkman and I worked out for Helium 3 and we have corresponding reinforcement effect for cuprates. So it’s very likely you’ll have superconductivity and anti-ferromagnetism. The second reason why I looked at the step with the optimal doping is that you didn’t have all that complication, if your state was undoubtedly just a superconductor at low temperatures. And that was the second reason for this mistake.
But if you do have animals, vegetables, minerals, and mugwumps, what would you view that as the task of theory in dealing with their systems?
The task of theory is to produce a reasonably good theory of the high temperature phase equivalent to the kind of a spin and free electron theory of heavy electrons, and then to find what the interactions are in that theory and what state you are going to get at lower temperatures, and this is not a program people have worked out. I certainly haven’t. I have vague ideas, but I have stopped working out my vague ideas at this point. I think it’s time for other people to do it.
On that note, we want to do something completely different perhaps talk a little bit about Phil’s involvement in our public matters.
All right. So actually we wanted to switch gears and talk a little bit about some of your more public activities, perhaps in particular I notice here that you testified several times before House Committees particularly on Star Wars and on the SSC. Could you tell us a little bit about that?
Joyce and I have been political since Caesar was a pup. I think when we bought our first house in Mendham in 1953 we put a big sign on in 1953 big sign on our front fence “Meyner for Governor”. It worked for Meyner for Governor, well we had been very enthusiastic about Adlai Stevenson, and then later on when we were members of the Somerset Hills Democratic Club, one of the most striking — there is this Somerset Hills or there used to be a Somerset Hills hunt meeting, kind of a point to point meeting, where all the fancy horsy people met in Christy Whittman’s bailiwick, and I had the experience of opening a booth for Adlai Stevenson in 1956 at the Somerset Hill Hunt Club Meeting. I didn’t sell many tickets, but I did oddly enough have quite a number of the grooms and farmers and so on who were around sneaked around and gave us a few dollars and took a few buttons and so on. But it turns out they weren’t real Democrats either. They were Democrats from the Democratic days of New Jersey before slavery, you know, the residues of the Democratic Party, the Southern Democratic Party. But we took their money anyhow. We have always been interested in politics. The next thing that we participated in very strongly was the famous, well not so famous and now forgotten, Great Swamp Controversy where the Port Authority had decided that they were going to put a jet port in what is now the Great Swamp Wildlife Reserve. We thought it was a terrible idea, not only because we lived there — well we didn’t live there, we lived in Mendham, but our friends the Holdens lived almost right smack in the Great Swamp. There was an organization that formed itself to oppose this. In those days it was not popular to oppose jetports; I mean you were stopping progress, and the political establishment was always saying, “oh great, it’s jobs, it’s jobs!” Well the first thing we did was stand back and look at our region and said we are in the most prosperous most incredibly rich region in Morris County, Somerset Hills, and so on. We are in the most incredibly rich region of the United States essentially, perhaps only second to Connecticut. The problem we had is slowing development down — what do we need two hundred thousand jobs for? Well, we joined this effort, the effort was led by people who were much bigger that we were. Kenneth Klipstein was a mogul at the time. Jim Fisk who was president of Bell Labs was definitely on board, he lived in the Great Swamp too and was a close friend of the Holdens. We got what turned out to be much better technical advice than the Port Authority was getting. They said we are going to need a fourth jet port after all. Two things: one is you have to keep planes so and so many minutes apart; and the second is the New York is always going to be the transshipment spot for travel to Europe. Everyone is going to fly London to New York and then New York to X. And we had people who actually knew what was happening in air traffic technology, and it turns out that actually in the factory were the jets that were going to over-fly us to Chicago and to Miami and so on, so that the second argument was wrong, and actually in the factory were the blind landing systems that were going to make it possible even in bad weather to bring in planes twice as fast. So there was no need for this, and we finally realized that it was a political ploy by the Port Authority to extend their domain by 40 miles, which is what they would have been able to do. They not only didn’t own the jetport, fortunately, but it wasn’t within the circle of eminent domain, they had to get it through the legislature. So this group wrangled. There were two extremely powerful Congressmen. One of them was Frelinghuysen, there has always been a Frelinghuysen in Congress ever since the first Congress, and the Frelinghuysen’s have always lived in Harding Township. Harding Township was going to be bulldozed into the jetport. So it was fairly politically unwise for the Port Authority to do it. But anyhow, we did it. In the end we won in the Legislature and then sealed the deal. We had enough rich people so they could just buy the swamp and give it to the Federal Government and then it was over. Joyce and I went around with decibel meters and we listened to jet noise, and that was a fake issue but we were willing to use a fake issue too. We also knew that new jets were going to be much quieter than the old jets, but we didn’t tell anyone. But this was a great learning experience because it’s a learning experience that the official organization is probably less competent than the political opposition to the administration. Unless the administration had really gotten to work and done its homework, it’s very likely that a pressure group like this will have better information on future technology. You do not have to be an insider to understand technology, and the people who are on the inside who have agendas are going to fake the technology, so you mustn’t believe them.
It’s certainly something that our colleague Frank von Hippel has demonstrated the effect of on various issues.
Yes, that was before I read Frank von Hippel’s book. Then after that Volker Heine and I actually ran a course at Cambridge on Science in Society. That was when I read von Hippel's book and joined the anti-supersonic transport lobby, but I wasn’t effective in that, I didn’t really have any role. But the other was a learning experience. We weren’t powerful in these organizations. Joyce was one of their Kiwanis speakers and so on. She, incidentally, for Meyner’s second term was a state wide chairman of the “Independents For Meyner”. The point was in Harding Township we had to vote independent because otherwise you had no say in how the town was run, so we were registered as Independents. She became Statewide Vice-Chairman of Independents for Meyner and nobody ever found out about her. Actually countywide, Morris County. Her co-chairman was a Mafioso.
Well fast forwarding in years to the Reagan era, in some sense there was some analogy there with your Great Swamp experience, namely that the people who were protesting the technology seemed to be able to learn more about it than the people on the inside. Did you want to talk about that?
Yes, there of course they have secrecy and they can pretend that unless you are cleared in the case of the ABM (anti-ballistic missile) or the Star Wars. Incidentally, I was in an organization at Bell Labs, a little known organization against ABM. We had our own ABM organization, and there was another story there. Tony Tyson actually was the guy who got into trouble because of that. Of course Bell Labs was the prime contractor for the original ABM, Safeguard ABM, and in the end we got captured by Tuck, he was a Kennedy operative who was well known for his for his practical jokes. One of his practical jokes was he put our ad on the back page of the Washington Post saying, “Look who’s against the ABM! The scientists who are building it!”
What were your main reasons for being against it?
Wasted money, the technology. Then there was the SST and then finally there was Star Wars. By Star Wars I had read Frank von Hippel’s book and I had also been going to the Frank von Hippel’s seminars for a couple of years. He had a lunchtime seminar I would go over and listen to. Sometime early in 1983 he had a visitor named Ashton Carter, who was at that time totally unknown but had been in the government, checking out ABM. He was actually employed by the Defense Department and he told the Defense Department the truth, which was that ABM was a bum idea. But he said, “Watch out,” quietly, “there is this pressure from this political organization under (what-ever his name is, I don’t remember his name), anyhow, there seems to be some interest within the administration on it, so look out for what’s going to happen on ABMs, you may be surprised. Sure enough March 1983 came the speech, and it’s all been gone into in great detail in Frances Fitzgerald’s book how that speech arrived and how the advocates within the government basically hoodwinked Reagan. I think he cooperated and he was eager to have this as an issue. And so there was a lot of astonishment, but not so much among Frank von Hippel’s friends, as to the speech. And a response to it developed at Cornell for us all to sign a pledge that we wouldn’t use Star Wars money, and it was signed in midsummer, and no tenured faculty was around here in Princeton except for Peter Meyers and myself. So we constituted ourselves a committee against Star Wars and started circulating the petitions. And we were very successful within the Physics Department; only the JASONs failed to sign it. We did quite well in the Engineering Department, and of course very well in the Math Department. So we got a respectable petition out. But this got me in the position of writing articles about it. Then George Shultz, who is a loyal Princeton alumnus, wrote an article in the Princeton Alumni Weekly in favor of Star Wars. I don’t know, I’d had other correspondence with the PAW objecting to one thing or another, and they said well this time we will let you object, so I was allowed to write a refutation. Wait a minute, it went the other way around, I wrote an article — I was allowed to write an article about Star Wars because they knew about the petition; then Schultz was allowed to write a refutation; and then I wrote a refutation of the refutation. I was delighted to have the chance to come at him the second time. I’m very happy with some of the things I said. I ended up saying, for instance, that a one of the reasons not to be willing to spend this enormous amount of money, this was ‘84 by this time, was that the Soviet Union was collapsing. This was also a little private information that came via Frank von Hippel and his group. He had a German visitor and a Swedish visitor and a couple of others visitors from overseas, and they said you know they are letting people demonstrate, he said there are things happening that never would have happened before and it’s different. The other thing was I had seen programs about the state of the Soviet Armed Forces which were absolutely right. They were sending planes up made of steel that we made out of titanium, we thought the MIGS were formidable but a lot of the essential parts had to be made of steel because they couldn’t make titanium well enough, and they were heavy and slow. Of course they had been used in Syria and they lost. Well I said, ‘Look, we’ve got the biggest group of allies, the most prosperous group of allies the world has ever known. Can you imagine Russia conquering Europe? Russia wouldn’t dare send its army into Europe, everyone would immediately all emigrate instead of fighting.” Anyhow, that’s just my reasoning, and as the final sentence, “It’s just silly to be defending yourself against this non-existent threat.” I was very happy that I said that so early, although there was really a large group of people who felt this way already. It never got into the CIA, of course; the experts never knew this. But the non- experts, the outsiders, all knew that the Soviet Union was collapsing at least five years before it did. I also got to testify, but that had no effect on that. I was very happy with this article. In particular the entire exchange was reprinted in Le Monde, so I got a big trip and a very fancy bang-up dinner with the editor of the Figaro and the LeMonde.
Did you meet George Schulz?
No I never met George Schultz.
So he didn’t get the dinner?
No he didn’t get the dinner. He didn’t come to the dinner. But you know, the French were just amazed that anyone in my position would be willing to come out against the establishment. Of course this is silly.
He was Secretary of State at the time.
He was Secretary of State.
And in his defense, the most reasonable figure in the Reagan administration.
Well that doesn’t say much. [Laughter]
Actually in the end he was the one that killed it. Because, you know, the people Ash Carter had been working with had never believed in it. They were fighting it all the time. And it was they who killed it according to Frances Fitzgerald, not the opposition from the public, not really the opposition from the public. SSC, that’s a different matter. There is a mythology that I singlehandedly destroyed the SSC. There couldn’t be anything less true. I didn’t testify before the House, I testified before the Senate. The Senate Committee never voted against the SSC. They had arranged that the relevant parts of the SSC were well spaced, that Senator Bennett who was on top, you know had lots of subcontracting in Louisiana. And the Democratic Senator lady from Maryland had lots of subcontracting in Maryland, and these were the powerful Science Committee chairmen in the Senate, and it was a lock in the Senate. I think that’s why they called me because they knew I wasn’t going to be a very effective advocate. It was in the House that it got killed, and who testified in the house was John Rowell and Ted Geballe among others, and they gave much harder hitting testimony, I believe. So in the first place I couldn’t have — I had been picked as a ringer by this Senate Committee that was totally biased. The second thing is what people right here in this department will tell you is it was not being well run; it was incompetently run, the management wasn’t very effective. The community wasn’t quite satisfied with its sociology. Well, some of them were and some of them weren’t but even high-energy particle experimentalists in this Department like Pierre Piroue had problems with the SSC.
I think the perhaps more interesting question is that traditionally there was sort of a gentleman’s agreement that scientists don’t attempt to hold each other’s excesses to account in public, so this was rather an unusual episode.
Yes, this is why I have two horns and a tail in the opinion of the particle people.
But leaving that, what was it that motivated obviously not just you but also Geballe and Rowell to object and stage a public stunt?
What really motivated us was their claims about spin-off; that was part of it. That’s what made you really mad. Well, let me tell you a story about spin-off. Steve Weinberg and the head of it at that time, I forget who, he was a nice guy but incompetent, and I all testified. The Head gave the party line. Steve was very meticulous in not claiming any connection with spin-offs of the SSC. He was very good about that. But the other guy had all the standard claims, MRI and so on. And I was in the room and I believe, I’m not sure whether Nico Bloembergen was in the room or whether Nico Bloembergen had testified to the same extent. But the literature was all over MRI, “Isn’t it wonderful?” MRIs as superconducting devises, we are developing superconductors for MRI, and that was such a blatant — Well, anyhow. So I went along and I said a lot in my testimony about MRI and about how this and other claims of spin-off were absolutely fallacious, absolutely wrong. So after the session one of the Senators came down, and he walked up to Steve Weinberg and shook his hand and said, “I want to thank you for MRI. It saved my nephews life,” or some relative’s life. That was what I think made many of us furious. That’s why Nico was willing to testify against it.
In a sense that the particulates were taking credit for accomplishments which they in fact had nothing to do with.
Absolutely nothing to do with, which they had impeded if anything by reducing the amount of money available for these other fields. And if they had been honest about that, had they left off the claims of spin-offs, I don’t know whether the scientific world would have been quite so angry. Well of course, you know, Bell Labs developed or started the high field magnet stuff. Westinghouse completed it and GE, mostly for MRI, and then these guys were just piggybacking on our technology on the superconductivity. And of course the magnetic resonance never had anything to do with, Nico did all that, and we at Bell Labs and actually Erwin Hahn is the biggest figure in that, because they use all these complicated pulsing techniques in the MRI. That and the fact that they jumped the standard peer review process. They went straight to Reagan and you know there is this famous instance in which Reagan said, “Throw long, throw long,” and they said, “We are going to leap frog all the little things and we are going to come up with the biggest damn accelerator in the world, and won’t we be proud of it?” And that was exactly the pitch for Reagan. And they have the nerve to call their laboratory the Reagan Laboratory, and that was not popular in the scientific world either. But my attitude was that really if they want us to go along, they had better talk to us, they better have gone through conventional funding avenues at least to some extent. This shouldn’t be an enormous piece of pork barrel legislation. Pork barrel was usually in Congress, but this was Presidential pork barrel.
Well on that note perhaps we will call this which has been certainly for the three of us I think an absolutely fascinating tour of your career. Phil Anderson thank you very, very much for taking the time and sitting down with us.
Well thank you. You have been a wonderful crew.