History Home | Book Catalog | International Catalog of Sources | Visual Archives | Contact Us

Oral History Transcript — Dr. Berni Alder

This transcript may not be quoted, reproduced or redistributed in whole or in part by any means except with the written permission of the American Institute of Physics.

This transcript is based on a tape-recorded interview deposited at the Center for History of Physics of the American Institute of Physics. The AIP's interviews have generally been transcribed from tape, edited by the interviewer for clarity, and then further edited by the interviewee. If this interview is important to you, you should consult earlier versions of the transcript or listen to the original tape. For many interviews, the AIP retains substantial files with further information about the interviewee and the interview itself. Please contact us for information about accessing these materials.

Please bear in mind that: 1) This material is a transcript of the spoken word rather than a literary product; 2) An interview must be read with the awareness that different people's memories about an event will often differ, and that memories can change with time for many reasons including subsequent experiences, interactions with others, and one's feelings about an event. Disclaimer: This transcript was scanned from a typescript, introducing occasional spelling errors. The original typescript is available.

Access form   |   Project support   |   How to cite   |   Print this page


See the catalog record for this interview and search for other interviews in our collection



Interview with Dr. Berni Alder
By Gianni Battimelli and Daan Frenkel
At FOM (Institute for Atomic and Molecular Physics)
June 18, 1990

open tab View abstract

Berni Alder; June 18, 1990

ABSTRACT: Use of early computers in statistical mechanics; the development of the Monte Carlo method and his role in the invention of molecular dynamics simulation; the people involved with the Monte Carlo method at Los Alamos and his own colleagues: Edward Teller, Marshall Rosenbluth, Nick Metropolis, Stan Frankel, John G. Kirkwood, Bill Wood; work at Lawrence Livermore National Laboratory; difficulties with acceptance of his work within the scientific community; computer simulation versus real experiments, past and present; brief account of his personal history.

Transcript

Alder:

Övery early user of computers. The idea being — one has the — I mean, just like in statistical mechanics. You have the equations, find means to solve them, right? And it was clear that hydrodynamics was a very early, you know, early stimulus to get, use computers, so — Well, you may want to do, Iím just saying you may want to do this, especially since at the end now there is again a connection between hydrodynamics and statistical mechanics. But it may be to a vicious circle [?].

Speaker (Battimelli or Frankel):

Well, I think we donít have necessary to define things that strictly right now. Just we have to find a starting point sufficiently well defined to go on and see at least we want to have this and this from this point after this point. And then itís quite natural, that since the field is so undefined in a way, thing will expand if the project actually goes on.

Speaker (Battimelli or Frankel):

Yes, and I also understand that Johnny will be going to the U.S. in November and actually be visiting many of the places where the early simulations were done. So with some suggestions on your side, we probably can make a list of the people who ??? ??? ???.

Alder:

Sure. That's one of the things we will have to do. And just finishóthe thing Giovanni was mentioning when we discussed, why don't we try to set up something like, for this field, something like to ??? ??? quantum physics, which are you familiar with —? That was a very large project ??? ??? all about the history of quantum physics, and it consisted of I donít know how many dozens of interviews and a huge amount of documentary material reproduced from microfilm, etc. But something like that ??? ??? collect as much oral interviews as possible with the people who are still around and accessible, and get — Thatís another thing where we should like to ??? ??? possible information from ???, collect documentary materialóthat is, notebooks, correspondence, whatever there is around. There may be some of this material still existing and exist in the archives, I donít know. ??? Ulamís [?] [papers], I donít know — They are at the American Philosophical Society. And I donít know whether there are any other collections ready ??? ??? for —

Speaker (Battimelli or Frankel):

I think what is probably fortunate —

Speaker (Battimelli or Frankel):

[loud noises in background] No. Maybe this was not such a good idea.

Speaker (Battimelli or Frankel):

Well, we can go downstairs if we ???. [loud background noise]

Speaker (Battimelli or Frankel):

If it goes on for two hours, well —

Alder:

In some ways, I think at least in localization, itís probably pretty fortunate itís mostly Los Alamos.

Speaker (Battimelli or Frankel):

Yeah.

Alder:

Because thatís where the computers were. And I think almost all the computation physics ???, certainly statistical mechanics ??? ??? ??? and the people associated with that. Iím not sure, well, there is an early calculation by Viniert [?] which probably preceded — Well, it was in the early, Iíve forgotten, in Ď59 or something like that.

Speaker (Battimelli or Frankel):

Ď59.

Alder:

That late. I thought it preceded — There was —

Speaker (Battimelli or Frankel):

It probably says here. It was actually Ď57 meeting, so —

Alder:

Yeah. But calculation is ??? older than that. You see, I just donít remember where people —

Speaker (Battimelli or Frankel):

No no. This is an autobiographical sketch of Viniert, and he says that there was a meeting in Ď57 where they discussed the possibility, and then after a lot of discussion he decided to try it, so he probably started after Ď57.

Alder:

But he did a very early calculation on radiation damage and solids.

Speaker (Battimelli or Frankel):

If you had asked me, I would have that it way preceded ours.

Speaker (Battimelli or Frankel):

Yeah, they started thinking of it in Ď57 and gave the report on this conference here in June Ď59, ??? ??? ???.

Speaker (Battimelli or Frankel):

He preceded ??? ??? ???.

Alder:

He preceded ???, but he didnít precede us. Well, because I wasnít aware of it. At that time anyway, right?

Speaker (Battimelli or Frankel):

So the earliest, Pastor [?], Ulam [?] and Fermi —

Speaker (Battimelli or Frankel):

None of those three are alive.

Alder:

No. But the one thing that you might want — I mean you certainly want to go to Los Alamos, and there is a Fermi-Montecarlo [?] machine, a mechanical device ??? ???. Have I talked to you about that or have you heard about that?

Speaker (Battimelli or Frankel):

Iíve heard about that.

Alder:

Itís in the Los Alamos science museum, and I saw it when I was at Los Alamos briefly last summer, but I had no chance to pursue it, but there is a write-up on it, and you ought to — thatís been mysteriously dug up. There is a collected — I have seen the biog — I have recently at Los Alamos or somewhere, a rather elaborate —

Speaker (Battimelli or Frankel):

??? ??? ??? Los Alamos journal in the issue room at Ulam [?] I think. Is that not what —?

Alder:

No, itís bigger than that. Itís a —

Speaker (Battimelli or Frankel):

Yeah. Thatís where newspapers by ??? and that kind of —

Speaker (Battimelli or Frankel):

But you think there is a more extensive —

Alder:

There is a huge book on it, a sort of a live history ??? ???, which may not do you any good, but itís a book, fairly thick and elaborate.

Speaker (Battimelli or Frankel):

Weíre talking about whatís going through the American Institute of Physics newsletter, the Center for History of Physics. They mention all the existing collections of correspondence and records. And I saw Ulamís papers mentioned and ??? ??? ??? the American Philosophical Society Library, ??? ??? ???. I donít know why theyíre in there, but —

Alder:

??? Los Alamos. I have seen a book — now I donít know, I see so many I donít know where or when, but it is a book that is really sort of a personal tribute to ??? many people.

Speaker (Battimelli or Frankel):

But that should be mentioned in this ??? ??? ???.

Speaker (Battimelli or Frankel):

??? ??? ??? Los Alamos science journal, because itís a thick publication that was there.

Alder:

Okay, okay. Maybe thatís it.

Speaker (Battimelli or Frankel):

And itís all devoted to Ulam.

Alder:

Right. So Ulam and Fermi, and Pastor was more a single excursion. The other guy you should definitely get is Bill Wood, who has superb ??? ??? ???. I mean, he is as meticulous as anybody, and probably can tell you more about it than anybody else. You know, heís off somewhere in Montana, and I think, I mean his records are probably by far the best on that phase of the work. Now Teller of course is the — Now Rosenbooth [?] you should — Rosenbooth, youíve got a little bit on that. See, Rosenbooth was in fact the first one who did quantum — I donít know whether you want to cover the quantum stuff, but I think you probably do, because thatís already going to be increasing importance. He was never written up ??? the early ???. He and the other fellow that is Mark Katz [?] has this national bureau, this standards publication 1949 in the early days ??? ??? ???. But again, he died, about a year or two ago, so — But those are very key papers. Katzís exists. I donít know whether you have a reference to that.

Speaker (Battimelli or Frankel):

Yeah.

Alder:

But I think Rosenbooth you have to — And Rosenbooth is now in San Diego. Letís see, he left Texas and went to I think itís either UCLA or ??? ??? ???. Now, heís hard to talk to, but you certainly should try.

Speaker (Battimelli or Frankel):

Who else is around of the old people?

Alder:

Teller is around, Metropolis [?] is. Metropolis, they had a meet, there was a meeting which I went to, and I went to Ulamís meeting as well. I donít think that was written up in the book. There was a meeting when Ulam retired from Los Alamos and went to Colorado. At that point there was a meeting at Los Alamos, whose proceedings I think Bill Wood organized. And part of it was ??? ??? ???. So you probably want to get a hold of that if you donít have that. But Bill Wood would know that. And, well, Rosenbooth and Metropolis and Teller are still around at Livermore. Both Tellers, Mitzi, he and his wife, so you, thatís —

Speaker (Battimelli or Frankel):

Rosenbooth ??? ??? —

Alder:

I donít know Marshall [?] that well. So that experiment. And then in the early very days, the question, you know, the question is how did that idea of Montecarlo nucleate. You know, thatís a very complex issue. I mean it was certainly out at Los Alamos, and let me tell you how I got involved, which is probably the most crucial point.

Speaker (Battimelli or Frankel):

Yes, letís start with you in World War II ??? ??? ???.

Alder:

I got involved, I mean thereís a collusion between all these people, thatís really the problem. And itís how to identify ex post facto where ideas come from. But Kirkwood [?] was certainly, who was my boss, my Ph.D. ???, was certainly —

Speaker (Battimelli or Frankel):

He was also Bill Woodsí?

Alder:

He was also Bill Woodsí.

Speaker (Battimelli or Frankel):

Advisor?

Alder:

But Bill Wood did something else on his thesis, something about optical rotation, which has nothing to do with Montecarlo. And probably only got involved — which you better get from — he certainly did not get involved in other things [?]. See, I got involved in Caltech, and with, Kirkwood was at the time at Caltech. And Bill Wood I think was a year ahead of me, and they went to Los Alamos. While part of my thesis was already to worry about hearts [?] spheres and the phase transition, which as you probably remember, Kirkwood had some ??? ??? ??? ??? ???. And the first thing he put a student on, a new student, is to try to apparently solve that ??? integral equation. And you know you use a Freed [?] calculator for awhile, and then you find thatís a pretty slow and tedious process. So thenóI canít remember this. Anyway, I got somehow talking to what was then the head of the Caltech computing center, ??? ??? is it Stan Franklin [?]? No, wait a minute. I was thinking about that. I mean now I get confused —

Speaker (Battimelli or Frankel):

And thatís the paper with Franklin ??? ????

Alder:

Yeah. Yeah.

Speaker (Battimelli or Frankel):

Okay.

Alder:

What was his name?

Speaker (Battimelli or Frankel):

Franco [?], yes, he was an aide.

Alder:

Slightly different. Iím just trying to remember. And he had been at Los Alamos ??? ???, so there was a large amount of collusion in being with Kirkwood in Los Alamos, Franco in Los Alamos, but I got involved with the integral equations and you know we started having lunch with Franco, whatever, and so we started talking about — You see, at that point we didnít know whether, people I guess still donít know whether these nonlinear integral equations ever have ??? ??? ??? solutions. And there were all these approximations. By the way, they of course, these nonlinear integral equations did show a phase transition ???. Ultimately turned out to be fallacious [?] single, because it shows up in one dimension, so that one knows what doesnít have a phase transition. But anyway, Franco and I started talking, and we said, ďWhy donít we do the problem right?Ē and this is how this whole thing got started. So we started on the Montecarlo ??? ???. And of course he knew, we started talking, he knew about Montecarlo when at Los Alamos. Kirkwood was always skeptical. And he, in fact, we did it in spite of him, interestingly enough, and he did not believe. It took us until the late Ď50s, just before he died.

Speaker (Battimelli or Frankel):

What were the main reasons why Kirkwood was skeptical about the ????

Alder:

Bill Wood would probably remember it much better, because he used to go to Los Alamos. You see, I left — I mean, I sort of did it on the s — I mean, I never really discussed it with Kirkwood, because he didnít know I was doing this. He thought I was doing his, solving his nonlinear integral equation. So I sort of just did it. And he had some, I think the argument had to do with — and Bill Wood remembers him very well, and you might read his article at the conference that he gave.

Speaker (Battimelli or Frankel):

??? ??? ??? that, yeah.

Alder:

Yeah, well he really — I think it had to do with, basically, the lack ofó He didnít believe that we had microscopic arrest ability [?]. But I would have to recall that argument for sure. Anyway, so Franco and I on the sly [laughs] just started developing what is known as Montecarlo Method, and now this had sort of an interesting history. Lewinson [?] was also, was a postdoc. I was a graduate student, Victor Lewinson was a postdoc, and so I guess I got him. He was helping me or I was helping him solve also this heart sphere [?] and nonlinear integral equation business. And so I dragged him into it. Iíve forgotten who dragged who in, instead of Franco. So we started working on the insertion tech — You know, the question was how to, there was the one thing thatís sort of interesting is at first we thought we would build up a system by just inserting one particle at a time to build up a high density configuration. That of course turns out ultimately not only not to be, not be able to go to very high densities, because you canít randomly pack spheres as local or ???. Itís very improbable, though in principal. The first idea was just to make, throw all the spheres in, calculate the energy and the ??? ??? ??? of course gets zero. Then the idea was to put in one at a time. You must remember at that time we only had IBM mechanical machinery.

Frenkel:

Yeah. That was a question I wanted then to raise, what the state of the art in terms of machinery andó

Alder:

This was in either 1949 or 1950, and it was only — there were no electronic computers available, except home built ones and maybe MIT, who were being used for other purposes. And the Maniac [?] at Los Alamos, which was really the first electronic machine there, was not available until the early Ď50s. And you have to check Los Alamosí records on that.

Frenkel:

I think it was Ď52 when the Iniac [?] became —

Alder:

Ď52. Because let me tell you the crucial things. I know we only had mechanical calculators [?], so our whole storage devices were IBM cards, and the program by plugging the ??? ??? ??? mechanical machine. So we did it once, and it became very clear that it couldnít ??? ??? ??? very high densities. And then we very quickly decided to put the, we then very correctly decidedóindependent of knowing what the Metropolis ??? ??? Teller were doingóto do what is now called Method ???. You know, putting it all in and jiggling. And then the interesting thing is, and Stan Franco — So we had a scheme, and Stan Franco then went to England to Manchester to the Feranti [?] machine, which was the first electronic machine, at least that we knew of, which we could get a hold of. So he actually tried out the Montecarlo method on that Feranti machine. And that must have been in the summer of Ď51. See, I graduated in Ď51, so it was just before I finished, or just during the time I was leaving ???, and the ??? ???, we, Stan Franco stayed at Caltech for a few more years before he decided to leave and work for an oil company. And I donít think heís alive anymore either. He went to — I think he died relatively young. He was ingenious, I mean absolutely ingenious guy. He was sort of, he and I guess Feinmann [?] must have brought him to — See, Feinmann was also very much interested in this, and he — Was Feinmann at Caltech? He came in Ď50 or Ď51, and he may have brought Franco to Caltech from Los Alamos, though I donít remember the back history ???. And Franco, it turned out, was much more interested in building a PC, which is now called a PC, and he was 30 years ahead of his time. I mean absolutely ingenious, at the time built a home built computer there. But then he went to an oil company with lots of money and disappeared. The fact is that the three of us left before Franco came back from Manchester [?] with the results, and as a result it took several years to write up. We felt it was so important. And Teller came to talk to us, and we got into communication with Los Alamos. And in the meantime — now this must be Ď51. I guess Bill Wood must have gone to Los Alamos in 1950, and I left in 195[?], because he left Caltech in 1950 and went to ??? ??? ???. And I went to Berkeley. And then I left the business for three years, three years, until Livermore basically got its first computer.

Frenkel:

So you started working on the thing when you were a graduate student in Caltech —

Alder:

Right.

Frenkel:

And then there is a three years or so gap between say Ď51 and Ď54 when you moved over to, from Berkeley to Livermore.

Alder:

Right, right. But, and thatís the period Los Alamos got busy, because they then got, and Bill Wood got busy. You know, I think that the Teller-Rosenbooth, the Metropolis sort of established a method and published too quickly their results on heart spheres I believe, and then I, and then Bill Wood must have taken it up. You better get those details on Bill Wood. And then I got back in Ď54 when I saw — I knew Bill Wood from Caltech days, and they didnít have a tran-, they I guess failed to find a transition, ??? ??? transition basically.

Frenkel:

They, you mean —?

Alder:

The Los Alamos group.

Frenkel:

The Rosenbooth.

Alder:

The Rosenbooths, yes. They failed either two or three dimensions, I canít remember what. I think it was heart spheres ??? ??? ???. And when I went to Cal-, when I went to Livermore, I say well, these people are doing Montecarlo so why donít I try something else. And thatís how molecular [?] dynamics was developed. You see, I was already a consultant to Livermore in Ď53-í54 probably, and then I went on ??? ???.

Frenkel:

Just to get — What were you involved with in those three years when you were in Berkeley?

Alder:

Well, I was an instructor. I guess I was working on mostly — Well, the man that got me to Ber-, two people got me to Berkeley, mostly Joel Hildebar [?], who was then chairman of the department, who was sort of interested in ???. So I went because there were no computer facilities available in Berkeley, I went back to the more integral equation type of things, which at least with great effort you could still do on the, on ??? computer. And sort of, I think I got involved in some experiments on liquids with Hildebar and his group. And the theoretical work was sort of integral equation stuff — which was at that time pretty new. You know, getting radio [?] distribution functions out of it. And Hildebar was very interested in that. You know, I sort of more worked with his group. But I was, it was clear to me that, I mean I, to me the important thing was go back to this Montecarlo method and the computers, and I then went to — I think I was sort of, well, I was letís say at Berkeley probably only two years, because then in the third year I went on a Guggenheim [?] to work with ???. I worked on dielectrics, as I recall, in those days. But just purely theoretical stuff. Big controversies which you donít want to get involved in, you know.

Frenkel:

Where were you in the third year? At Guggenheim?

Alder:

I was in Cambridge, England, uh-huh, and in Lyon [?], half a year each. And were — The reason I must have chosen those places is because John Pope [?] and Buckingham [?] were then just — You probably donít know that. There was a big controversy with Furling about dielectrical ???. And I had written a paper during the Berkeley days, and so I went to Cambridge because these people were just working on that as well, and then to Lyon, where Peter Masure [?] and Mondella [?], somebody called Mondella I think were still in Lyon as well and were working on dielectrics then. So that must have been my main interest in those days. And then I didnít do any computing. And then I went back and I went back to Livermore basically to get into computing. The idea was, I wasnít going to take on Montecarlo since Los Alamos was obviously already heavily involved, and thatís how we — I mean, itís a fairly simple idea, ??? ???. I talked somebody else into it. He was a group leader or someone I could talk into working with me together, and very bright chap by the way. And then we did more carefully, looked again at this heart sphere transition, and then found the discrepancy between what we had and what Los Alamos had, and then we had a huge correspondence in which Iím sure Bill Wood has most of that, if not all of the files. He keeps haunting me, telling me the things I said in those days. So, anyway, thatís how molecular [?] dynamics got started.

Battimelli:

You now make it sound as if it was a very obvious, a logical step to start doing molecular dynamics. But at the same time, ??? ??? ??? had not thought of doing —

Alder:

Oh no, no, Peter and I thought about that, and I remember talking to telling about this. He said, ďHopelessly complicated.Ē I mean, people thought it — Thatís really the big surprise, that molecular dynamics ultimately turned out to be competitive like Montecarlo. We had Bill Wood and Kirkwood and many people got involved on the relative efficiencies ultimately between molecular dynamics and Montecarlo, but in the early days, very early days, people didnít think Montecarlo was at all feasible to be practically, efficiently on a computer. And that was the big surprise. Actually I remember the other, the crucial thing is this meeting in Brussels, which I think was the first time we talked about — this was Ď56 or Ď57.

Frenkel:

Six?

Alder:

Ď56. And I remember ??? Kirkwood really, he didnít believe in Montecarlo, but he really believed in molecular dynamics. Because I remember flying over with him to the Brussels meeting and showing him for the first time the results on an airplane or something, and he was really impre — Well, partially because it finally could test his — See, he had been working in transport theory as well, and here was a chance to really test some of these ??? ??? ??? analogies that ??? had.

Speaker (Battimelli or Frankel):

It may be that Kirkwood was more or less skeptical at least about molecular dynamics than Montecarlo method just because, also because the foundational dynamics look much more like the things he was actually doing.

Alder:

No, I think the foundations, I mean, they are unassailable foundations to molecular dynamics. So Montecarlo, you know, there are a number of ways you can play the game. And it took some convincing of everybody, including you know Teller and Metropolis. They were worried about whether one was really doing the ??? problem right. And you know, and actually one of the early — All of these things are very obvious now, but the checking of Agodig [?] hypothesis, which was time averaging, was the first detailed example of which is in fact ??? ??? ???. So maybe there was, once that came up maybe even the skeptics got, I mean like Kirkwood, when we showed that we got the same equilibrium [?] by Montecarlo as by time averaging. Got less worried about the foundations of Montecarlo then.

Speaker (Battimelli or Frankel):

Were you at all influenced by ??? Fermi [?] ??? ???, or were you aware of it?

Alder:

Well, [laughs], I probably became aware of it sort of late. I mean not when we started out. We had no idea of theó Thatís actually, actually that precedes, thatís probably the first molecular dynamics experiment, right?

Speaker (Battimelli or Frankel):

But itís never considered as such ??? ??? ???.

Alder:

Never ???, right, but in a sense it is. And ??? ??? that also of course has, since its ??? intuition it took a long time to disentangle. And probably put some discredit, but I mean, of course these are slightly ??? ??? forces, and they are here with ??? ??? ??? forces, but it probably, you know, it didnít give numerical experiments the best of reputations to start out. Now there is, you know, in the event of — thereís the whole business of the heart sphere transition of course had a huge number of skeptics, and particularly ???. It took a long time for people to accept the results of the transition.

Frenkel:

I saw in the proceedings of this meeting that is edited by Ferguson [?], the medibody [?] problem I think it was in Hoboken [?], New Jersey, that there was actually a panel discussion shared by Ulambeck [?].

Alder:

Yes.

Frenkel:

Where at the end of the discussion he started to have a vote on the heart sphere transition, and I think that actually a slight majority was against. And those were not sort of stupid people.

Alder:

No, no, no, this was a —

Speaker (Battimelli or Frankel):

When was that?

Frenkel:

And also in Ď57 I think. Thereís a scandal. The ??? proceeding did not get published for some seven or eight years. I mean, itís one of those horrendous stories. It was either ??? ???, I canít remember. It was in honor of, it was dedicated toódo you remember? — either Jung [?] or Lee [?] or somebody like that. It was some memorial meeting. I think ??? ??? ??? I think may well be still ??? ??? ???. And they had a conference in Ď57, and it didnít get published until ???.

Alder:

But there was, there was a vote. I mean, it used to be what used to be called then the ď64 Dollar QuestionĒ was ??? correspondents to this television program where if you won the grand, $64 was the grand prize. And, but those are very early results on sphere transition. I mean, we didnít have enough statistics. You know, we could run a hundred particles, a hundred collisions an hour, I mean very early machines, and the statistics were bad, the systems were small, and it took some ten years of having intensive ??? to understand the number dependents and then do the two-dimensional system where we actually connected by a bundle [?] of ??? ??? ??? ??? ??? ???. And there was, I think there still are Jung or Lee or one of those is still a skeptic as this point. I mean, some people still donít believe anything numerically generated unless you ??? proof, right? But I mean eventually most people came around. Mark Katz — I gave once a lecture, I think it was an ??? meeting which it was its 30th year, that must have been the early Ď60s, 30th year of the ??? relations, ??? relations at Brown University. You know, you give your hourís talk on the heart sphere transitions, ??? must be used to that, and you know you talk and you talk and in the end you show a picture — which turned out to be very important from a pedagogic [?] point of view. We show one side is solid and the other side fluid, and Mark Katz said ???, ďWhy did you spend an hour talking? Just show the pictures.Ē You know. So — This by the way is an interesting lesson. I mean, the graphic displays which in fact may well be also the first ones.

Frenkel:

Thatís a comment point that ??? ???, that most people start ??? ??? this kind of work then end up by saying, ďFinally people got convinced because they could see the things.Ē

Alder:

Yeah, yeah. No, but the crucial thing here is the history. You might want to look into that a little bit on graphic displays which — Of course itís becoming more and more important, and more and more people are doing it, but in those days it wasnít easy to get graphic displays, and I think that the point is it convinced more people than ever. And you know we got into Scientific American, which was then the prestige journal. They asked us to write an article. Tom ??? and I wrote an article on the liquids configurations ??? —

Frenkel:

When was that? Later on.

Alder:

Yes, it was later. But I can get you those, I have those Scientific American reprints. And we used to sell thousands and thousands of copies for, it was used for high school students for demonstrations. And this was the early days of graphics as well. And then ultimately we made films actually, and those pictures got into covers of textbooks, you know, ??? ???. But the point here is that the graphics has been an essential tool to convince people. Maybe a false tool, but anyway effective pedagogues ??? ???. So we actually, of course we originally developed ??? ??? ??? and transfer coefficient, but we more or less convinced the rest of them about what we were doing. We spent some ten years just on equilibrium things. And a very close collaboration with Bill Wood. I mean, I at least to Los Alamos, I mean the only, Iíve forgotten, probably late Ď50s, I canít remember when, but we had these controversial results and we just decided the best thing would be for me to go out to Los Alamos, spend a summer there, and just in detail compare the results. And ultimately it caused me to recompare it well.

Speaker (Battimelli or Frankel):

Who else was around doing this sort of thing? Say, was it just confined to Los Alamos people and you ??? ??? ??? any other people around thinking along the same lines and doing similar stuff?

Alder:

Well, the one guy that I think of very highly is Zevi Zalsberg. Now, he was very much involved in computing as well. He died very young. I remember he died on the way to come to spend a summer with me. Now, I canít remember which year that was. But he also used to go to Los Alamos, and he was a part of the early building of a computer at Rice University ??? ??? to use. So he made a fairly large number of sort of fundamental contributions to heart sphere or, you know, in general to computational physics and the statistical mechanical area ??? ??? ???. Iím not saying he ever did anything very central.

Frenkel:

He also collaborated with Bill Wood I think.

Alder:

Oh yeah. He regularly came to ??? to Los Alamos every summer. And thatís where he really did his work, but he died very young as I say, and —

Frenkel:

Werenít they the first to actually study spin systems, Eising[?]-like systems?

Alder:

Say this again?

Frenkel:

I had the impression that they were the first to study Eising-like models.

Alder:

I think the that the Eising model ??? ??? you, thatís true. There is a man called Chestnut who I just ran into, Chester Salzburg [?] and Bill Wood did some Eising lathis [?] model work. But you know itís sort of, itís interesting, they may be the only ones that did both. I mean, I think the Eising model work on early days of computer, Yang [?] certainly was heavily involved in that, Yang and his, I believe his son did some very early simulations on the Eising models. But I think that may well precede what we did. Do you know the urgence of the Eising model simulations?

Frenkel:

No, I was just, I never looked into the ??? ???.

Alder:

The group of people that did that were rather different than the people doing heart sphere work.

Speaker (Battimelli or Frankel):

Still are.

Alder:

Still are. Except the ??? ??? game now is forcing them into similar things, but they never got into the central, but itís true that Salzburg, there was a student whose name is Chester or Chestnut or something like that, and Bill Wood did some Eising model work. But it never really — there is one thesis then, which I probably have or Bill Wood has, on the Eising model, by this student. But I think it, well itís, I mean, though the Montecarlo algorithm is of course the same and much simpler, the two fields just never really overlapped as far as I know. I mean, you know, they check the two-dimensional, they got some, ultimately some three-dimensional critical point results ??? ??? ??? but itís sort of a separate offshoot using the Montecarlo ???. Now then there was of course I think historically the computers were only at Livermore and Los Alamos, so I think the computers were the big electronic computers were confined to these two DOE laboratories. Well, Brookhaven had some, and thatís probably how Liniac [?] got involved. The Oak Ridge people did a lot of neutron transport, but never got involved in a statistical mechanical Montecarlo method. And then of course the method really didnít take off until computers became widely distributed and the applications became just incredible.

Speaker (Battimelli or Frankel):

A side question. When was Livermore Lab established?

Alder:

Livermoreís Lab was established probably in Ď52. Ď52 was the beginning. There was a, it was partly run by the University of California, partly by Standard Oil, and then it started out, ??? appeared, and so in Ď52 was the very early beginning, and I think Ď53 or Ď54 the University of California ran it all by itself. But you know, they really tried to staff that laboratory and tried to ??? anybody they could find to work there. And I know Teller, because of the Montecarlo work in fact, he wanted me to go there. And so I just started working there ??? computers. And so I just got drawn into that whole — But, you can get the early history of Livermore, I can certainly — Are you planning to come to Livermore?

Speaker (Battimelli or Frankel):

Well, Iím planning to come to Los Alamos, Berkeley, so I may find the time to —

Alder:

We can get you the early history, I can get you the, I mean itís something they documented you know in history. And the computing center can tell you what computer ??? ???, you know. But we basically used them all. And every once in a while we did a problem, and you see the computers were heavily used, and not for our stuff.

Frenkel:

But thatís one thing, I donít know, this may be a significant question, maybe not, but one mentions Oak Ridge, Los Alamos, Livermore, these are all more or less offsprings of war job, and so all this computer business came out basically as an offspring of wartime scientific activity, and I guess that most of the time was devoted, at the origin at least, to work on problems that actually related to, what, thermonuclear fusion products [?], things like that. How much was left for people who just were there using those machines to do non-military related job, what were the constraints?

Alder:

Well, I think the statement to be made is that the Department of Energy, the Atomic Energy Commissionís predecessor, first got hold of the big computers before ???, because they had a clear necessity to weapons ??? use them. And the reason that — Itís a complex reason why did Montecarlo, why was it originated there. Partially because the computers were there. But partially because itís also useful, but the hope was, and itís been partially realized, that these Montecarlo calculations can be used to generate properties of materials where itís very hard to expand, itís a very ??? and very high temperatures. So thatís, so itís a bunch of bright people thinking about that problem in a long range, recognizing the existence of this potential, this method and its potential applications. And so which came first — But both of those aspects are important. So itís not just, it is true itís just pure science, but it does have its potential.

Speaker (Battimelli or Frankel):

As I understand from what I read, before they applied Montecarlo Method to do the H??? or whatever it was, it was started as a sampling device to work out on ??? ??? programs —

Alder:

Yeah, but thatís a different algorithm, you know. You follow — itís essentially, intellectually, a different one, because you, you know, what you are doing when you follow a — Thatís true, and thatís why people start thinking about Montecarlo, but itís just what you do is you follow a new ??? ??? two feet of concrete and you just say, ďWhatís the probability of hitting a calcium nuclei in the concrete?Ē and it has a stochastic probability of scatteringó Itís a series of scattering ??? ??? ???, whatever the material randomly located nuclei in this concrete, oh, thatís got to be neutron, and see whatís the probability of it emerging, this neutron transport. While though itís in a general class of Montecarlo calculations, in some sense the statistical mechanical Montecarlo is really slightly misnamed, because itís not, itís a mark-off process, not a totally random process. And so itís an intellectual extension beyond neutron. And but you know, the point was it wasnít sort of a needed thing. So you know in the early days of Livermore I was the man who worried about whatís called now the equation of state, or the only person worried about — The reason I was probably paid for at Livermore had nothing to do with Montecarlo. They needed somebody who could the equations of state, which is properties of — you probably know what that is, the thermodynamic properties, the pressure bonding temperature in any ??? for materials and explosions, either chemical or nuclear, where they didnít know what the ??? was. But you know, my price was, implicit price was well, if Iím going to go there, I am going to also do other things in a long range support of these kinds of things. So thatís how these things was tolerated by management, because thereís a usefulness and to get good people to work on this you needed some better planning [?]. But the machine time, obviously, the first priority was on this planning stuff, right? And so what we basically did, what I instituted as part of the thing is to steal all the time that wasnít being used on the computer, the idea being, see, most of the time we were just then gathering statistics, and it doesnít, we donít really care whether we get the statistics in one day or one week, so we just sat in a background mode and utilized excess computer time. So whenever there was nobody was using it, we just came in and — And that helped. My good friend at the Livermore computing center was quite happy to let me do that, because it showed total utilization of his equipment, so he could ask for the next computer. And it helped him enormously to persuade the Atomic Energy Commission in fact to always drop the best, latest computer into the Livermore Laboratories. And we in fact initiated the development of, design of their next computers. So in that sense the Montecarlo Method was a good filler in excess computing time. And we got lots of time in those days, especially when a new computer came along, you know, then it took the other people quite a while to learn how to use it, and you know we had relatively easy algorithm.

Speaker (Battimelli or Frankel):

When you say ďwe,Ē you mean you?

Alder:

Tom Wainright [?] and I. And we had for many years, in those days one had programs. Well, many of the people didnít have — The machineís operation was sufficiently complicated, and I had a programmer for many years that — which is probably slightly different than Bill Wood. Bill Wood always programmed himself, but I always had a programmer, a young lady that stood up, got up in the middle of the night when machine time was available, you know.

Speaker (Battimelli or Frankel):

??? ??? ???.

Alder:

Thatís right. Well, she was very dedicated and interested. Now letís see, who are the people at Livermore. Well, Bill Hoover is of course one —[glitch in tape for several seconds hereÖ]

Speaker (Battimelli or Frankel):

Bob Wainright?

Alder:

Tom Wainright.

Speaker (Battimelli or Frankel):

Background. What did he —?

Alder:

He was a solid state physicist from the university, got his Ph.D. I believe, went to University of Montana where Bill Wood is from. He was just a very bright, quiet, good thinking physicist, and I just persuaded him.

Speaker (Battimelli or Frankel):

You brought him to —?

Alder:

Yeah, I started dropping into his office, and he got excited and — very effective collaboration. Helped him out, and helped with the analysis, but he — he was a very good bouncing board. Very quickly we established a rapport to complement each other. And then eventually ??? ??? ??? at the end. Somewhere along the line he — he doesnít have much energy, unfortunately.

Speaker (Battimelli or Frankel):

Is he still around?

Alder:

He retired early. He retired ??? few years ago. Even during the last ten years at Livermore he sort of just became a consultant. But he was a highly respected citizen. Just, I donít know, after you work with somebody for ten years you probably have exhausted each other, so we just separated. I mean, and he went off on consulting on other more practical problems, and I donít think he ever published anything in physics.

Speaker (Battimelli or Frankel):

I have one question about working with the programmer. It seems that if the programmer has no knowledge of physics itís a bit difficult to communicate. How did that work?

Alder:

Well, that was a big problem ultimately. I mean, she had a masters degree in mathematics, and program — Now with, for classical molecular dynamics and Montecarlo, I mean the physics is sufficiently simple that you can communicate and tell her about the algorithm. But for the quantum mechanics which we are doing now, itís so complicated. What I now have is a Ph.D. physicist that does programming rather than — and thatís a very serious, you hit upon a very serious problem. And the other thing of course which is sort of serious when you have a programmer, is that you lose control of what you are doing because you are totally dependent on her doing things right, programming the things right. So Bill Wood, who is a stickler, would never trust anybody and wanted to do it all himself. Of course he had Jerry Urpenbank [?], who he went to talk to at Los Alamos. Iíve forgotten what year he came in, but they too worked together for many, many years ??? ???. But I depended on a programmer. Has both advantages and disadvantages. It allows you to think in a broader term than just technically making sure the program is right, but on the other hand it —

Speaker (Battimelli or Frankel):

You are dependent on what this person does when you go down to the ??? ??? ???.

Alder:

Say this again?

Speaker (Battimelli or Frankel):

You say it gives you wider control of the thing, but you ??? ??? ??? someone elseís —

Alder:

You just, you can have a wider — I mean, you donít get involved in the details and therefore have more time to think about the consequences of what you are doing and get involved in other things. I mean I didnít do just molecular dynamics in those days. I must say for years I spent a majority of my time on molecular dynamics.

Speaker (Battimelli or Frankel):

But it probably also requires a lot of physical intuition to be able to judge whether results make sense or not if you donít do the programming yourself.

Alder:

You build in checks and balances to make sure, you check up on the programmer by —

Speaker (Battimelli or Frankel):

By the results.

Alder:

By asking her to calculate something which you know — Itís one of the hardest things in Montecarlo, by the way, is to know whether the program is working or not. Because itís a stochastic thing. I remember once calculating something, some ??? distribution furniture [?] or something ??? dynamics probably, and the program was, everything made sense, but ultimately we discovered that there was this very small mistake in the program which took us months to discover. You think you make gross, as you say you make grosser physics checks, check on the program, but mainly you can spend a majority your time programming, which is extremely time consuming to you ??? ??? — especially in the early days when you had to do it in assembly language. And not only did we do it in assembly language, we had very limited memory. If we had 20,000 words of memory, that was already ten years after we started. I mean, early on we had a 100 words, and then you had to pack words together to use, you know, if itís an integer thing you are trying to represent instead of just a ??? point number, you could pack three integers into one folding card number, and that makes the program very much more complicated, much more complicated. But, so you had to do a lot of programming because you had limited memory and make the program efficient. In the early days I mean that took 80 or 90 percent of your time ??? ???. Of course now you can be sloppy and with more memory and ???. So programming was not an easy task in the early days. The amount of tools that were available, and the machines were much less reliable, you know. We had mercury delay lines, which you know the signal was just bouncing back and forth until you wanted it ??? fluctuations caused the memory to get lost or the tapes were not readable or the vacuum tubes in the early days failed you. At one time we actually had a machine was a — they still sometimes do this now for very reliable, when they want a very reliable computation, we had a machine which was doing the calculation twice, just checking the vantage point, just to prove the reliability of the calculation. So you had to fight [?] that equipment and ???.

Speaker (Battimelli or Frankel):

I have another question which is totally different. It goes back to people in Los Alamos.

Alder:

Okay.

Speaker (Battimelli or Frankel):

The ??? ??? five man people at least, Metropolis, the two Rosenblooths, and the two Taylors, and we wondering, we were discussing ??? ??? ??? what their respective contributions actually were, who actually did the leading character, who had the ideas, what basically the role of Teller was, whether he was there just because he was kind of the boss in that place or —

Alder:

Well, look. You can certainly leave the two wives out. They were just dragged in to keep busy. I mean, donít quote me on that officially. Now the question between the three others, I mean they are all excellent people, and you know Teller is a very dominant personality and he, you know, he probably talked, the idea probably may well have come either from Fermi or Ulam. Thatís one of those things you are going to have a hard time tracing down, I suspect. But Teller grabs onto the imaginative ideas very well, you know, and he may well have stimulated the other two, who were very competent people. But Teller is not one that you know is very busy, and so, you know Marshall is extremely clever, and so is Metropolis. You know, Metropolis was probably in charge of the computing center at that time. Am I correct in that?

Speaker (Battimelli or Frankel):

Yeah, yeah, he was in charge of sort of using the Maniac for ??? applications.

Alder:

So he was a natural guy for Teller to drag into this enterprise. And probably Rosenblooth I mean and Teller got along very well. And I should probably take that back about Marshall Rosenbloothís wife. Was she ??? ??? ???? She may have been a very good scientist in her own right. Would you check on that? Because Iím not sure theyíre still married and all this, but and there was some problem, but Iím now confused as to whether she might not have made a significant contribution. But suddenly — and changed her name subsequently after she ???, but my guess is sort of Teller by the force of his personality, and having talked to all — I mean, Joe Mayer [?] was involved too, and he, I mean I have talked to him and he said heís had similar ideas in Houston. Also consult a little bit. And so these people, Teller always gets the, I mean just by force of personality and superb reputation, talks to all these famous people and hears all these ideas and then decides, ďAh, thatís something I really want to get involved,Ē and then he probably organized these very two competent people. Certainly Metropolis is an obvious choice. Now how Rosenblooth came into it — But Rosenblooth and Teller had been buddies for umpteen years, so how that nucleated is my guess is Teller and then dragging the other two in. And then they had a lively discussion and they all got to work, played on a computer, and thatís how this thing developed. And how we develop it in — I mean, the question of how independent we did it at Caltech, we still, I personally cannot tell you. It may have been transmitted via Franco. We may have generated ourselves, or Kirkwood may have told us about it, but I doubt that. I mean, my guess is we just independently ???.

Speaker (Battimelli or Frankel):

This is talking still of the very early period, Ď49, Ď50 or Ď51.

Alder:

Yeah.

Speaker (Battimelli or Frankel):

And that was Montecarlo all the same.

Alder:

The fact is that we used independently the same ???. And I have talked to Teller about it. I mean, I havenít talked to Teller about this recently, but in those days, and if you notice he acknowledges our contribution, because independent — and we wrote it up rather late, because we all dispersed. And I sort of insisted we write it up and get some credit for thinking about it. My impression was we were independent. Itís not very difficult to come to that conclusion, that how to do the Montecarlo. Once you try —

Speaker (Battimelli or Frankel):

Still there seems to be a wide gap between the neutron transfer type of Montecarlo and this sampling of the ??? ??? ???.

Alder:

But see, Mark Katz had already had the idea. The idea of a stochastic solution of solving problems, itís ??? Mark Katz knew about that. It certainly, Ulam Mayer [?] have been a kind of connection betweenówhen was Katz ???. Katz, was he back at Michigan? Iím not sure. He used — One of the early computers was the CIAD [?], the SWAK [?] and the CIAD, which were two computers built by the Bureau of Standards, SWAK standing for west and CIAK standing for east, and two computers, one located at the bureau in the east and maybe one in the west, Iím not quite sure where, and Mark Katz in Ď49 already used the stochastic solution. So during the war these methods became ??? ??? Montecarlo became prominent, and then naturally bright people think about using it for other ???.

Speaker (Battimelli or Frankel):

I donít remember whether we discussed this before in detail, but then the question is, how exactly did the idea come for you later on when you came back to Livermore in Ď54 to switch from Montecarlo approach and invent molecular dynamics? Which ultimately turned out to produce results that were ??? ???, but ??? ??? ???.

Alder:

I donít, well, itís just I think the best way to say this, I wanted to find an alternative numerical method, because I wasnít going to do Montecarlo since Los Alamos had ??? by that time, and I said well, I mean I guess you just think about — I donít know, itís just one of those things that you think about one day and I canít really trace the origin of that idea. You know, I probably just sat down, how ??? we do it — What do you do, and then you suddenly start talking, and suddenly you think itís not that difficult and suddenly you do it, right?

Speaker (Battimelli or Frankel):

Were at that time also involved in the theory of transports and hearts [?] view [?] systems?

Alder:

Thatís true. Part of my thesis was to apply — and this was in Ď51, my last part of my thesis was to apply the current [?] transport theory for thermal conductivity, and that was a significant section. I did that not believe Kirkwoodís theory, I mean I just went through the formality because he insisted on it. But I was certainly familiar with his transport theory. Very complicated theoretical method to calculate thermal conductivity by his methodologies and friction tunnels [?]. So I knew about transports. I donít know whether that had any influence. My major motivation was not to do transfers. My main motivation, since I believe in hearts view transition more or less because thatís the way we were showed by the ??? and Kirkwood integral equation. I thought maybe the Montecarlo people had missed it, which it turned out they did, and find an alternative other way of looking at the problem.

Speaker (Battimelli or Frankel):

I mean of course when you started molecular dynamics, Kugal [?] had not yet published his paper. I mean, anything like the idea of green kubo [?] light [?] relations did not exist when you ????

Alder:

Yeah, well, thatís not a very important point. Yes, it does. It did. We in fact, I mean it was clear to us — and I think itís still clear — that to impose external boundary conditions like a temperature gradient to measure thermal conductivity of a velocity gradient to measure, ??? would impose such an enormous barrier, along with gradients, that we never thought we would get the transfer coefficients right. But what we were then doing, thinking about, was using an ID Einstein [?] relations for the diffusion coefficient. And the Einstein relations, if my memory serves me right, for the transfer coefficient for ??? diffusion were already written down by Helfand [?]. Now, remind me again when was the Green-Coomer [?] ???.

Speaker (Battimelli or Frankel):

Oh, Coomer was Ď57, so Iím not quite sure when Green wrote his contribution.

Alder:

It precedes that, but of course nobody believed it or knew about it. But we, well, there was the corporate school of transfer coefficients of which Helfand was a member, later ???, who I already knew had written down the equivalent of Einstein relation. And early on we just studied the diffusion or ???, and by the time we got to the other transfer coefficients I believe Green-Coomer relations were already —

Speaker (Battimelli or Frankel):

But anyway for the hearts [?] ??? diffusion ??? ??? ???.

Alder:

Rights. ??? ??? ??? that type of coefficients. Thatís right. Exactly. So it was fortunate that these things more or less came with the new [?] way of trying to calculate the transfer. But you know, we spent ten years on equilibrium before we — We in Ď57 already did h-therms [?] and diffusion coefficients for the Brussels conference, just to demonstrate there is time dependence on ??? could do, but the equilibrium, to establish credibility and so on we must, my impression is we spent ten years, more or less, doing equilibrium properties and me saying, ďWow, we really should get to transport,Ē but we never had you know enough machine time or energy.

Speaker (Battimelli or Frankel):

I have another question that always surprises me. If you look at people doing computer simulation, it seems to be almost from the start, letís say from the work of Ulam-Parker [?]. A diversion is the people who go immediately to quote-unquote ďreal systems,Ē and well I would say the ??? you have followed, and that is looking at simple system theories. Have you any idea why so many people started so quickly actually pretending to do real systems whereas in fact they were doing I would say caricatures of real systems, and so you have ??? ??? simple ??? ??? ??? the answers are the real systems.

Alder:

I think this is just a human phenomena, trying to — Itís true, that was before [?] we immediately jumped to applications ??? ??? ??? real systems in applications. Itís a very easy thing to do, and I would think even nowadays there are very few people worrying about the foundations. Most people, the vast majority of people are doing what I call application of the applications are immense, and very useful, and as you say they have empiricals, intermolecular potentials trying to simulate real systems. I think itís just relatively easy once you get the algorithm in the machine, itís an easy way to make a living, right? You simulate. I think it takes less of a — I mean it takes more of a character I suppose to worry about the foundations. And, you know —

Speaker (Battimelli or Frankel):

??? ??? ??? more receptive public, that I mean they have all these experimentalists who ??? this theory, whereas your audience is for theoreticians who might feel skeptical or insecure.

Alder:

Thatís right. I mean it depends on whether you grew up as a ???. Well, of course the early days we were all theoreticians getting into this computer business. There is a new breed of people who just start out, consider the tool, and they donít really have a theoretical background in material science or chemistry. So they just simulate and try to interact with experiments. I think your theories are any as good as mine about why people do that, but it is —you have to be well founded in theory I think to know what experiments to perform that would lead to some insights, and I think these people are just not that motivated.

Speaker (Battimelli or Frankel):

Just expanding on this, we started with Don Frank [?] saying that in his opinion this field is going to be really ??? likely as the starting point of new approach in a new field in theoretical physics, letís say theoretical physics and you seem to agree —

Alder:

Yes, I do.

Speaker (Battimelli or Frankel):

So, would you just, talking freely, but try to characterize what are reasons why this kind of approach can be designed as to build, play [?] with the birth of a new way of doing theoretical physics?

Alder:

Well, I think it represents an intermediate area between theoretical and experimental, which ??? ???. You know, as Don just says, its function can be to, since you are completely in control of the simulation you test the foundations of theoretical physics. On the other hand, it can do more realistic simulations than what has been previously possible purely on the learning of theoretical means. So you have a much more realistic comparison to expand — and you can of course do experiments, computer simulation experiments where the experiment itself has difficultiesóseeing the details of the atomic structure, the correlations. These are very hard things. Since our experimental tools are not yet at an angstrom [?] resolution most of the time, and here you can really include some detail, resolve things on a distance and time scale which has been experimentally ???. So it can in some sense outdo experiments, and in the theoretical side it can really you know well controlled situation hopefully test the realó I mean, is molecular chaos [?] valid or —

Speaker (Battimelli or Frankel):

Yeah. The interesting question is ??? ??? is a point of view more or less commonly held today, it looks like a puzzle now to see how theoreticians were reluctant to accept the idea when it was ???, because from what you said it seems that skepticism mainly came from the theoretical part of the community rather than from the ??? ???.

Alder:

There is this usual skepticism.

Speaker (Battimelli or Frankel):

Why was it so difficult at the beginning to see that computer simulation offered this —?

Alder:

Well, because it doesnít provide a general theory, you see. It provides only, like any experiment you have a detailed fourth [?] point in the experimental curve, right? And so, itís still better, I think ultimately you still want to end up with a general theory, even after — Computer experiments are only ??? again ??? ??? ??? to a theory which, you know, some general theory of whatever phenomenons you are trying to describe. And so from that point of view these are computer simulations are like experiments, and therefore — But what is interesting, just like real experiments if you do a bunch of computer experiments you can discover a general theory which the theorists have not been able to — in ideal situations — not been able to discuss.

Speaker (Battimelli or Frankel):

It seems that just when you started doing these things you came out with unexpected results.

Alder:

Well, the heartsphere transition of course was not unexpected. I mean, itís been predicted on shaky grounds before, and thatís well of course one of the spectacular results that once you believe that from numerical work that the heartsphere transition is real. It sort of put it on a more sound foundation. But otherwise for equilibrium properties we really didnít end up with any spectacular results. We could, you know, we could calculate seventh sphere of coefficient by the Montecarlo Method and so on, which they had only previously been able to calculate three and so on. But I think the really unexpected results came only out of molecular dynamics ??? ??? ???. Otherwise I would say it showed that one could study phase transitions of crystal structures all by one general method ??? ??? the main problems. But I would not say there was any — That is spectacular, was how it showed — what it did is put the method on the map in the sense it showed that what it could do. But I think the real surprise came, one surprise really came out of the ??? calculation.

Speaker (Battimelli or Frankel):

And that was later on.

Alder:

That was later on. I think ??? ???. But the long time table [?] was probably not until the middle Ď60s. And thatís only because it took us a lot of time to get around to doing that, because [?] it would occupy ??? ??? main properties. Establishing credibility I think. I must say the acceptance of the method was a struggle. First with Kirkwood unusually so, but the method was generally accepted as being valid by most people fairly quickly on. But this way to do physics was hardly — I mean, I didnít get offers from Harvard University every day saying come. And I think computational physics, as I found out, the first chair [?] in computational physics was just established here at Harvard this year or last year. It was ??? ???. And it has taken a long time for many fields to accept computational methods. As a man who only does computational methods, to be as a legitimate professor at a major first rate university. I still think there is some prejudice against that to this very day. But you hear more and more it really, I mean real people, real first rate theoreticians are accepting this method, and I think that this is just a personal view which has to do with the high-energy physicists who so dominate physics. Anyway, they are now forced to do computational physics to solve their quantum ??? ??? ??? dynamics equations, because they are so highly dimensional they canít get to first base anyway, so they build computers even to, because they need some powerful techniques that they use Montecarlo Method. And once they started using computational tools, then I think it became ??? ??? ??? as a real ??? approach to physics.

Speaker (Battimelli or Frankel):

We could have a short break and have tea now. Thereís tea outside, and weíll come back. [tape turned off, then back onÖ]

Alder:

Öcollected works, and there are several volumes, and several people wrote introductions to these volumes, and I wrote one of them, and there were several of them. But Irvin Oppenheim — [?]

Speaker (Battimelli or Frankel):

Oppenheim?

Alder:

Oppenheim.

Speaker (Battimelli or Frankel):

In what year?

Alder:

At MIT, chemistry. Was the overall editor, and ??? ??? contract with Mrs. Gartworth [?], and probably has most of his scientific work ??? ??? ??? ??? ???. He wrote at least one if not two books with Kirkwood on thermodynamics, and so thatís a good, probably the best source for Kirkwoodís collected works. He obviously had an enormous influence on theoretical statistical mechanics in the United States.

Speaker (Battimelli or Frankel):

Thatís actually one of the things that struck me while ??? ??? ??? one of those round table discussions, that we were discussing the heartsphere ??? transition, the remarks Kirkwood make first of all strike you as very much to the point, and also as very modern. I mean, he speaks the language that I now understand. The other ones speak a language that I donít understand, or hardly understand.

Alder:

Who were the other ones?

Speaker (Battimelli or Frankel):

There was a Mack Yum [?], all the, I mean the whole ??? —

Alder:

Right. Yeah, Kirkwood was, I mean, certainly was a major contributor to make statistical mechanics of liquids, development of liquid, modern, I mean these integral equations. He and Devon [?] in France were really the foun — And Kirkwood developed a school in the United States. I mean, Wood [?], all the people, my colleagues, were of that school. Now Joe Mayer [?] I guess was the other one. I donít know whether he was at that, probably was. He was certainly at the first ??? meeting. I went to that, theó

Speaker (Battimelli or Frankel):

The one in Ď57.

Alder:

Ď57. Well, I think the — Was that just follows the Brussels conference? I canít remember. Thatís the following year. The Brussels conference Ď56, the ??? ??? —

Speaker (Battimelli or Frankel):

The Brussels conference was Ď56 and ??? ??? Veranda [?] meeting in Ď57.

Alder:

And that was run more or less by ??? ???.

Speaker (Battimelli or Frankel):

In fact I was going to ask you whether, I mean your recollections so far in — Because ??? ??? ??? you were there and Bill Wood was there and Julie Port [?] and ??? ??? ??? dynamics and Montecarlo, and I wanted to ask you what your recollections of the reception of people there who ??? to those things were.

Alder:

I was a young whippersnapper, [laughs], and these were all giants to me. But I mean you know, we had been in consultation starting in Ď56, Ď57 with Kirkwood, and I think by that time people had already gotten used to the ideas that these machines could and did make a major contribution. And my guess was it was one of the highlights in fact of that meeting, when Bill Woods ??? ??? results. And certainly there were, the ??? ??? ??? talking about, Stevens was then saying a year later — See, it already had enough impact that 50 percent of the people believed it ??? ??? really at the very beginning of our results. There were still a few skeptics about whether the thing would go away when we studied bigger systems, you know, but that was really, you couldnít — I mean the results were unassailable, I mean that there was this rare fluctuation between the two, liquid and the solid phase in this intermediate density machine. Because we could never make that coexist — which is of course a rather unusual thing. And you know we had these explanations for small systems and so on, and the question then would these two curves merge as you went to larger and larger systems. And then I must say that Bill Hooverís [?] method of equating the chemical potentials of this, you know, he had a method of taking the solid all the way to low density by the single occupancy idea.

Speaker (Battimelli or Frankel):

Bill Hoover.

Alder:

Did I say Bill Hoover?

Speaker (Battimelli or Frankel):

Yeah.

Alder:

And then so you could calculate the chemical potential, the solid phase you could calculate, chemical potential, free energy of the liquid phase from integrating from basically the perfect gas ??? and then showing them to it. That helped enormously, and that must have been in —

Speaker (Battimelli or Frankel):

Ď67.

Alder:

Fifty?

Speaker (Battimelli or Frankel):

Ď67.

Alder:

Ď67.

Speaker (Battimelli or Frankel):

At least the publication was Ď67.

Alder:

Okay, well, it was certainly, I mean he was working with me very strongly in those days. I just canít remember, maybe it took that long.

Speaker (Battimelli or Frankel):

When did Bill Hoover appear on the scene ????

Speaker (Battimelli or Frankel):

I think he finished his Ph.D. work around Ď64.

Speaker (Battimelli or Frankel):

??? ??? has a paper with him with ??? about that time.

Alder:

But he was already a postdoc then, you see. He did some work on some odd-shaped [?] particles, I canít remember. And then he —

Speaker (Battimelli or Frankel):

Well, he probably started with ??? ??? ??? I think.

Alder:

He started with the ??? ???, but he spent two or three years at Cornell [?] postdocing I think before he came to Livermore, and we worked very intently. Again, ??? ??? coefficients and developing other techniques to show the validity of ???. Again, we worked together. I donít think he was as effective a cooperator [sic] as Tom Wainright in terms of working with me on a machine, that is. But he developed — he was more an independent soul, and went off and did his own thing. And very effectively, and later on also in ??? equilibrium he developed — I mean, in some ways competitive methods to what we were doing, he was trying to develop. Very effective. Certainly the first few years we did a large number of things together in equilibrium.

Speaker (Battimelli or Frankel):

I was wondering, Iím not sure whether you consider this relevant, but I thought it would be nice if we had a short, personal background of the people who we interview, you know, something like a bit about your early history, background, ancestry, or whatever, where you come from, how you came to be ??? at that time, and ??? ??? ??? if thatís okay with you.

Alder:

Yes.

Speaker (Battimelli or Frankel):

Maybe you can best tell what you —

Alder:

How did I come to where —?

Speaker (Battimelli or Frankel):

Something ??? ???.

Alder:

Well, anyway, let me see. I think the relevant things is that I was born as a Swiss citizen in Germany, and left in Ď32, around Hitlerís time, so my very early years of schooling I was then at that point the same age as ??? ??? ??? years education I was in Germany and then the rest in Switzerland, all the way through, halfway through the gymnasium in Zurich. And then left to the United States, Berkeley as a matter of fact, spent one year at a high school in Berkeley and then as an undergraduate to Berkeley, chemistry. That was during the war. And I missed going to the Manhattan Project probably by one year being too young. I eventually got drafted into the American Navy and spent two years of electronics technician, doing, preparing radar on naval ships. Andó

Speaker (Battimelli or Frankel):

That was still during the war?

Alder:

This was, yes, this was up to, well it was during the war and then I didnít get discharged, you know until about Ď46 and I went back to Berkeley to finish as an undergraduate in chemistry. Then it took one year to get a Masterís. I wasnít so happy with chemistry, I mean I didnít like experimental work, so I went for one year in chemical engineering and didnít like that either, and got a Masterís degree. And then decided theory was my bag, and then went to Caltech with Kirkwood in Ď48. The choice was then between Pauling and Kirkwood. I had sort of a chemistry background by then, so I really wanted to do I think physics, but I was sort of stuck in chemistry, so I did chemical —

Speaker (Battimelli or Frankel):

At that ??? point which, now itís a difficult question to ask because itís probably vague, but this matter of disciplinary boundaries and these sort of ???, we are talking of people which are, what, you were in chemistry for example, Kirkwood was ??? ??? chemist, other people ??? ??? were physicists, and you have all these different — it seems to be a typical field where the boundaries of establishing disciplines and you build up something new drawing material from here and there and cross-fertilizing ideas and so on. Do you have the feeling that at a certain point this development made up some kind of well identified subsector or group of scientists, or it was just a ??? defined intersection across disciplines, or what?

Alder:

I think it was initially. Now itís much more ??? ??? ??? ??? ???, but initially I think it was theoretical chemistry and sort of physics. You know, statistical mechanics has always had this two-legged thing. Because its applications is in liquids and thatís an essential part of the chemistry, and physicists more like solid, they like more solids. So initially it was — lots of people in those days got degrees in chemistry, chemical engineering, and drifted over, lots over to ??? physics. I mean, Teller has this background, ??? has this background. Chemical engineering is not a bad training, because it, you know, it tries to be interdisciplinary complex and it tries to reduce a complex situation to a simple ???. And I donít think — I mean there was a different attitude I think you indicated. You couldnít at the ??? ??? ??? Yang [?], who have sort of a more abstract mathematical view, while the — At that point chemistry ??? ???, what Kirkwood was doing was also hard to understand by most people. Itís become more, these methods have been more accepted, these integral equations, but at that time it was, you talked to an average chemistry ??? about integral equations, you got a pretty fast loss. But now itís become more accepted, and these very abstract methods of Yang and Zeroís [?] have — the methodology has, itís been a thing where instants of trying to solve a problem can be generalized and ??? ??? ??? technique. So, but itís become very interdiscipline. I mean the chemists on the biological side, and ??? on the material side, and I was using Montecarlo with zeolites and DNA and polymers and I think people like the geophysicists are now using it to simulate silicates, the time pressures in the interior — I mean, applications are just everywhere. This has become very interdisciplinary. And many people now make a very good living first introducing these simulation techniques to their ???. But originally, letís see, Teller I guess at Los Alamos, well, you know, as you know, physicists, ??? ??? physicists and chemists developed a methodology. Anyway, so thatís how I ended up at Caltech, and then I went to finish my own personal ???, so the choice then was between Pauling, theoretical, and Pauling had too many students and whatever, and Kirkwood had too many students, but they decided I should work for Kirkwood, ??? ???, so thatís how I got started, and after that I went back to Berkeley. And I must say I left Berkeley, I mean I still spend half my time in the Berkeley Chemistry Department, as you probably know. I mean, but at that point the chemists, particularly at Berkeley, were not very appreciative of theory. They had no theorists. Thatís a very long history dating back to Lawrence and Lewis, who were the dominant physicists and chemists at Berkeley, and they just didnít believe in theory. And in a sense that what we understand ??? ??? ???. So I mean I was sort of a pioneering theorist there, and barely tolerated, and I sort of ??? ??? out to where I was more welcomed as a theorist. So there is a — but this is peculiar to Berkeley. But chemists werenít very advanced theoretically. Chemistry is basically organic thinking, organic chemistry, right? And it still is probably, and theorists are more and more tolerated, but at that time —