Robert Finkelstein

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ORAL HISTORIES
Portrait of Robert Finkelstein

Credit: Tim Lynch

Interviewed by
David Zierler
Interview date
Location
video conference
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Interview of Robert Finkelstein by David Zierler on May 10, 2020,Niels Bohr Library & Archives, American Institute of Physics,College Park, MD USA,www.aip.org/history-programs/niels-bohr-library/oral-histories/XXXX

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In this interview, David Zierler, Oral Historian for AIP, interviews Robert Finkelstein, (deceased in August 2020) formerly professor emeritus, department of physics, University of California, Los Angeles (UCLA). Finkelstein describes his early interests in physics and his undergraduate education at Dartmouth College, and he describes his formative summer at Columbia University, where he studied under I.I. Rabi. He discusses he graduate work at Harvard University under the direction of John van Vleck, and he discusses van Vleck’s fundamental contributions to quantum mechanics. Finkelstein describes his postdoctoral work expanding on Niels Bohr’s capacity to deal with magnetism, and he discusses his work with Francis Bitter at Massachusetts Institute of Technology (MIT). He describes his conscription to the Navy during World War II, where he worked on mine warfare, and he explains his close relationship with George Gamow and his work on tunneling in quantum mechanics and general relativity. Finkelstein discusses his postwar work at Fermilab, where he became interested in meson physics, and he describes his position at the Institute for Advanced Study at Princeton as a postdoctoral researcher under Robert Oppenheimer, where he continued to work on mesons. He describes getting to know at the Institute, he discusses his first contact with the Feynman diagrams, and he recounts how Jack Steinberger used his calculations which were in agreement with the diagrams. Finkelstein discusses his decision to join the faculty at UCLA, and he explains his opinion that Julian Schwinger was a “deeper” thinker than Feynman. He explains the originals of his unitary field theory, and he describes his contributions to the concept of supergravity. At the end of the interview, Finkelstein explains his ongoing interest with improving upon the Standard Model, and he reflects on the incredible level of understanding about the cosmos that has been developed over the course of his career. 

Transcript

David Zierler:

This is David Zierler, oral historian for the American Institute of Physics. It is May 10th, 2020. It is my great pleasure to be here with Professor Robert Finkelstein. Robert, thank you so much for being with me today.

Zierler:

Let’s start with the first question. Robert, can you tell me about your early childhood and your family?

Robert Finkelstein:

It was all about baseball, and Billy Duffy and the Pittsfield Hillies. Billy Duffy was a retired GE worker who lived across the street from me.

Zierler:

OK. Can you tell me what your father did for a living?

Finkelstein:

My father was a doctor, a urologist.

Zierler:

And did your mother work outside the home?

Finkelstein:

No. She worked on the Census.

Zierler:

And Robert, did you go to public school through 12th grade?

Finkelstein:

Always public school.

Zierler:

When did you start to show an aptitude for math and science?

Finkelstein:

Oh. In junior high.

Zierler:

Was there a particular area in science that you were interested in? Were you always interested in physics from junior high?

Finkelstein:

[pause] I think I always had an interest in fundamental physics

Zierler:

Why did you choose Dartmouth? And when did you decide to major in physics?

Finkelstein:

I chose Dartmouth because of their policy in the library. They had open stacks and permitted me to write my own courses.

Zierler:

What do you mean, “write your own courses”? As an undergraduate, you wrote your own courses?

Finkelstein:

I wasn’t able to take advantage of that until I was a senior, I guess. But then as a kid, I was interested in general relativity, and I was allowed to pursue my interests. And I was able to essentially write a course in general relativity. And Dartmouth was good enough to let me do this course as part of the regular curriculum. So, I had one student who was my closest friend at Dartmouth, but that’s what they did.

Zierler:

When did you declare the major in physics? Right away? Did you enter Dartmouth declaring a major in physics, or you took that on later on?

Finkelstein:

I declared a major in physics before arriving

Zierler:

Now, you had a very special experience. the Columbia summer school. You had a formative experience there.

Finkelstein:

Yeah. That’s important. Because there was no course in quantum mechanics at Dartmouth, and this was the only way I could at least get it on the books. So Rabi was himself a very important man. What Bohr had done was the quantum mechanics of the atom. But Rabi was doing quantum mechanics of molecules.

Zierler:

What was Rabi like as a person?

Finkelstein:

Very friendly, with a strong sense of humor.

Zierler:

Why did you choose Harvard? When did you make a decision on experimental versus theoretical physics? Who was your advisor? And what was your dissertation on?

Finkelstein:

I chose Harvard just by reputation. I made a decision on experimental versus theoretical because it’s all I could do.

Zierler:

When you mean that’s all you can do, is that because you felt like you were better at theoretical physics?

Finkelstein:

Well, I made model airplanes. That’s all I could do. [laugh]

Zierler:

I see. Right, right. [laugh] OK. And who was your advisor at Harvard?

Finkelstein:

My advisor was Van Vleck. RUTH: What was your dissertation on?

Finkelstein:

I don’t remember. But he won a Nobel Prize for his work on the quantum mechanics of magnetism.

Zierler:

Did he give you your topic to work on, or did you come up with your topic yourself? In other words, was your topic an outgrowth of the research that he was doing himself, or was your research your own project that you came up with?

Finkelstein:

[laugh] Very strange reasons. [laugh] Van Vleck—what he did was like what I spoke of before. He passed from the quantum mechanics of the atom to the quantum mechanics of the extended materials, especially paramagnetic material. And at the point I came to Harvard, he was clearly an outstanding theorist.

Zierler:

He was clearly an outstanding theorist? Did I hear that right?.

Finkelstein:

Oh. [laugh] Oh. Van Vleck was—at the time I asked him to be my advisor, at that time he was working very hard on a paper that he had been asked to write. And he did a lot of work, and I think he had a full schedule, so he invited me to be a co-author. And that paper turned out to be—for Van Vleck, it was so important enough to reference in his Nobel Prize talk. So I had the remarkable experience [laugh] of being a kid who didn't know anything, [laugh] writing a paper that was referenced in a Nobel Prize talk. And if you don’t believe it, I can read it to you!

Zierler:

I believe it. I believe it. [laugh] I want to ask another question before we get to question six. It’s sort of off the page. And the question is, what were some of the most exciting things in physics during your time at Harvard? In the late 1930s and early 1940s, what were the big questions that were being asked in physics?

Finkelstein:

Oh. Before you come to that, I wanted to add one thing to this first paper. The paper was actually very important, because it was the paper that was used by Maiman when he invented the optical laser.

Zierler:

In what ways did quantum mechanics offer a new way of understanding physics or how the universe works?

Finkelstein:

Well, it changed everything. [laugh]

Zierler:

Changed everything. How? How did it change everything?

Finkelstein:

Well, you begin with the simplest classical object, which was the hydrogen atom. And you understood it only classically, and you had no idea how the spectrum was developed. The spectrum as it was an entirely quantum mechanical thing.

Zierler:

Did it upend previous theories, or did it complement previous theories in physics?

Finkelstein:

It did both.

Zierler:

What did it upend?

Finkelstein:

The general answer to that is that it upended everything that it didn't clarify.

Zierler:

Was that exciting to you personally, that you were there at the beginning of this revolution?

Finkelstein:

I'm sure I was. But I don’t think I appreciated it.

Zierler:

Right, right. Maybe because at the time, it wasn’t clear how revolutionary it was. In retrospect, it was clear?

Finkelstein:

Oh, I knew that there were overriding problems that no one had any idea what to do with them, in that respect. I mean, everything—there was so much that was not understood.

Zierler:

Was anyone talking about a grand unified theory in those days? Was that a concept that existed?

Finkelstein:

No. And for Einstein himself, it came as a big surprise.

Zierler:

How did World War II affect your career trajectory? What were your motivations to put your expertise to the service of your country?

Finkelstein:

Well, in the first place, after I finished my thesis with Van Vleck, what I had done in finishing my thesis was working on all kinds of ways of expanding Bohr, Niels Bohr, so that he could deal with problems in magnetism. And Van Vleck was a very careful, extremely careful man. And so I had to deal with a lot of real experimental material, not theoretical.

Finkelstein:

Well, since he happened to be working on problems of magnetism, showing how magnetism is affected by quantum theory

Finkelstein:

Yeah, this is a really big event in my life, because I was working with Van Vleck. Van Vleck was working closely with Francis Bitter at MIT. And they were working on problems of magnetism. And then at about that time the Nazi submarines were beginning to drop mines on the sea lanes to our country. And so there had to be a response to that. At that point, Van Vleck and Francis Bitter at MIT had organized this anti-mine group, and Van Vleck sent me to Bitter. Bitter asked me what salary I wanted and so I knew I had to answer that question before, so I discussed it with a fellow graduate student at Harvard and we decided on a number and I told this to Bitter and Bitter said, “Oh, that’s too low.” He didn’t even write it down. [laugh] So he came up with a number and I remember what it was; it was nine dollars a day. [laugh] Anyway, that’s not what this story is, but I think you’ll have to take it as it comes. So as a result of my conscription, I became a part of this group working for the Navy in mine warfare. So I did that, and I had in fact one significant success.

But I then asked if I had permission to change to the operational research group from mine warfare, to something which I thought would be more important to the war, and this was the study of shock waves and detonation theory. And I did get transferred to this other group. That’s I think a rather indirect answer to your question.

Zierler:

Robert, can you tell me about how you got to work with Gamow?

Finkelstein:

Yes, I was also fortunate to meet George Gamow, who was also part of this group. He had just escaped from Soviet Russia after having enjoyed a Fellowship with Bohr. Right after the Bohr atom was published by Niels Bohr, he had asked for a fellowship to Europe because he couldn’t learn about things in Russia. And he asked for a fellowship that would take him to the most famous places in Europe, which was Germany of course. So that’s where he went, but toward the end he asked also to visit the Bohr lab where the really important discoveries were being made.

And what he did was to visit Copenhagen and, most important, to meet Bohr. And he spent about a day there. At that time, Bohr had quantized the hydrogen atom, number one in the periodic table. It was not known how to go on to number N, helium, and lithium, and so on. But the enormous difference, of course, was that while classical problems involving two or more electrons become very difficult and all Bohr had done was to solve hydrogen which was one electron. So, in particular, there were a lot of experimental results which remained untouched, in particular the radioactivity of uranium. The uranium was at the other end of the periodic table, so Gamow devised a way of handling uranium completely different; he had introduced a new technique. And he was enough confident in his method. Aside from the fact that a number of people had picked up the same method, he was the first to introduce it. And it was called “tunneling” in quantum mechanics. One thing that happened that doesn’t happen in classical mechanics is that when an atom, when a particle is trapped by a potential [energy barrier]—but anyway, I won’t touch upon it, but it was a completely novel way of handling problems like that. It turned out that Oppenheimer had also discovered it in a different connection.

Anyway, Gamow apparently immediately knew the solution to the uranium problem. So, he could send a published paper from Copenhagen to the press and that was enough for him to write a book about it. He did this in Copenhagen, and his fellowship would last a day longer. He didn’t have time to work on it, so Bohr asked Gamow what he wanted to do. It was obviously something he didn’t want to neglect, and so Bohr asked Gamow how long he would like to work on it. [laugh] So he had discovered something first rank and he had a day left [laugh] on his fellowship. He stayed a year and published everything.

Zierler:

In what ways did Gamow recognize the significance of this?

Finkelstein:

What apparently made a very big impression on him was the fact that he could jump from hydrogen to uranium. And so, the first paper that I found was a paper with a German physicist, in which they tried to estimate the energy of the sun. So, the sun is another object of the same nature, but has very many parts. I know that he had at least been influenced by the success of the uranium business, so that he probably figured that, it worked one, two, three, four, up to uranium—that the same explanation that he had given for uranium was actually operating throughout the periodic table and was responsible for solar energy. And the biologists were also very much aware of the problem; they knew that the sun was producing huge amounts of energy, but they didn’t understand it. And they came out with different time scales. The physicists and the biologists were in disagreement. But it turned out in the end that the biologists were correct in estimating the time scale.

Zierler:

And I understand Gamow was also involved with General Relativity at this time.

Finkelstein:

Yes. It turned out that he was also interested in General Relativity and taken a course in GR in Moscow with Friedmann but with boundary conditions different from Einstein. This led Gamow to the speculation that the first appearance of the gravitational field was as a nuclear explosion and that whole history of the universe from the big bang to the present is as now believed but with the details now available in the language of nuclear physics. At the time, this was not accepted and people even joked about it. But Gamow is now recognized as having been at the forefront of this idea.

When Gamow arrived in the United States he was without a job. The U.S. government offered him a professorship at George Washington University, and the opportunity to stage a conference, which he chose to focus on the sun’s energy. It was also an opportunity to bring many more famous physicists from Europe to the U.S., rescuing them from the war, and many of them remained in the U.S. That conference was the first time it was understood how the sun converted its nuclear potential to energy that sustains life on Earth. Hans Bethe won a Nobel Prize for the work he described at this conference.

Zierler:

So when you asked to be transferred, was it because you were eager to put your physics background to more relevant use?

Finkelstein:

Certainly. Yes.

Zierler:

Did you achieve your goal? Did you feel like you were able to do that?

Finkelstein:

Yes and no. It was the Navy, [laugh] and the Navy was not so well organized. I achieved my goal in the following sense—that the work that I actually did was anti-submarine warfare, and the submarines were Japanese. And the way the submarine was operated was that the torpedoes, when they went under the opposition’s ship, were fired by the magnetic structure of the ship. So it was quite an elegant way of firing those torpedoes. They didn't just crash into the hull; they went under the ship and they were turned on by the magnetic field of the ship. Well, that depended upon the magnetic field of the ship and also it depended on the magnetic field of the Earth. Because, see, the submarines operated in the Pacific, in both the North and South Pacific. And if the ship, when it was being prepared to go to sea, if it was not prepared properly, it was not prepared to adjust to a magnetic field’s latitude. And what I noticed, and I'm sure other people noticed, but at least this is something I think I got in my record—that something had to be done about the way that this torpedo was prepared. They had to be prepared in such a way that the magnetic field of the torpedo could be altered. That’s a long answer. I don’t know how far I got from your question.

Zierler:

That’s great. Were you ever concerned of a German land invasion on the Eastern Seaboard?

Finkelstein:

No. No.

Zierler:

So then what was the overall strategy of defeating the German submarines? What was the purpose?

Zierler:

Oil. To protect the oil traffic.

Finkelstein:

That’s the theory, as it was on our side. And we needed the oil.

Zierler:

Did you serve in the war through the duration, until 1945?

Finkelstein:

I didn't serve in the Navy. I worked for the Navy department, and was paid by the Navy. And my life schedule was completely determined by the Navy. But I didn't wear a uniform.

Zierler:

And then what happened after the war ended, for you? What was your next career move?

Finkelstein:

Oh. After the war ended, one of my friends who I got to know during the war became head of the Fermilab in Chicago, and he offered me a position at Fermilab, although I was not a nuclear physicist at the time. But then I of course had to learn nuclear physics, immediately. But it wasn’t what I was interested in.

Zierler:

Did you take the job? You went to Fermilab?

Finkelstein:

Yes, I did. And I wrote a couple papers at the Fermilab. What I was really interested in was fundamental physics, and the new field at the time was meson physics. Mesons had not been picked up by laboratories. That is, it was clear that mesons were doing important things, but it wasn’t clear what they were doing; there were no mesons. So at that time, I was asking to go into a field where not much work had been done. And at that time, I don’t know how it came about, but it was at that time that I applied for a postdoc in this field, this new field. And the two people who were pushing the field were Oppenheimer and Pauli. So I applied for a postdoc with Oppenheimer and Pauli, and Oppenheimer replied to me. [laugh] So this was the next phase. And it just so happened that at just this time, Oppenheimer himself was offered the position as the director of the Institute in Princeton. So that was my first visit to the Institute, as a postdoc of Robert Oppenheimer, moving from [UC]Berkeley.

Zierler:

And when you went to the Institute, did that end your tenure at Fermilab?

Finkelstein:

Yes. Well, it wasn’t really, I had the opportunity to go back, but I didn't want to go back.

Zierler:

OK, so I have a question about Fermilab, before we move on to the Institute, and that is—was your sense that when the war was over, Fermilab was concentrating on non-military research? Or was the prime aspect of their research geared towards national security and military matters, even after the war ended?

Finkelstein:

They did as much as they had money for.

Zierler:

Now we're at the Institute. You're talking about your time at the Institute.

Finkelstein:

When I arrived at the Institute, I had no projects submitted, but Oppenheimer had ideas which I was happy to take up. And so I wrote my first paper on mesons. Which was an important paper, because there weren’t any other papers.

Zierler:

Did you take your knowledge that you gained from Fermilab and apply it to your new project at the Institute?

Finkelstein:

To a degree. Because my interest was not really on what they were doing at Fermilab. It was on the new things, on the mesons. Well, the other big advantage of starting work on mesons theory was that it led to new kinds of fields, and it led to a unitary field theory. In fact, a unitary field theory had not previously been proposed. I was very pleased to notice that our idea, my idea, was used as a basis of a research program by Heisenberg.

Zierler:

How did you come to meet Einstein, and what was it like to work with him?

Finkelstein:

Oh, it was pure chance. I was at the Institute for Advanced Study, and lots of things were going on, and at the Institute they tried to get outstanding people in all fields, in all kinds of work. And one of the big projects was primarily directed by von Neumann. Incidentally, I had the good luck of knowing—getting to know von Neumann during these years. And I got one paper out of it while I was still working on hydrodynamical problems. Because at the beginning of the war, people worked on everything, because they didn't know what would be the key projects. But there were hydrodynamical problems of all sorts, and hydrodynamical problems were hard partly because non-linear equations had not been studied so much. And the techniques we were doing in non-linear physics were not understood. And I had the good luck—von Neumann helped me on one of these problems. And it was a good thing.

Zierler:

What did you need help on? What did von Neumann help you with, exactly?

Finkelstein:

The statement of the problem as it appears in my paper. It’s the normal reflection of shock waves. It’s the simplest thing you can imagine, except that [laugh] when the shock is—when a sound wave is reflected, then what it does after the reflection is quite simple. It’s just the superposition of what goes in and what comes out. But with shock waves, those fields are non-linear, and you can’t add non-linear fields with impunity. So he devised a very neat way to handle this problem. And I can say that I solved the problem analytically that Chandrasekhar solved with a computer. Which I was nothing like Chandrasekhar, but this was a very nice result.

Zierler:

Should we come back to Einstein? We didn't really talk about Einstein. We can move on if you have not much to say. But my question was, how did you come to meet Einstein, and what was it like to work with him?

Finkelstein:

This was the time of the war and we came into this project at about the same time. And Einstein was already an old man. His only condition on the Navy was that we send our problems to him, not bring him to Washington. And so there needed to be a liaison person between our group and Einstein, and I was that person at the start. He was generous with his time.

Zierler:

And so what kinds of issues did you convey from your group to Einstein?

Finkelstein:

The same thing that he was working on and I was working on. They weren’t big problems. But it was quite a wonderful thing for me. I went to his home on Mercer Street in Princeton, every week, with what I had done and learned what he was doing. They weren’t big problems. Beyond that, I think—I was very young. I had just gotten my degree. He sensed that I was somewhat uncomfortable working with this great man. So [laugh] he was very, very nice. It was a very thrilling experience for me.

Zierler:

Let’s go on to number nine. I want to know when you first came into contact with the Feynman diagrams.

Finkelstein:

The first calculation that I did when I became a postdoc of Oppenheimer. Yeah. But at that time, you could use Feynman diagrams, but you didn't have to. I mean, you could in principle use them, but they didn't exist at that time. When I became a postdoc of Oppenheimer, Feynman and Tomonaga had not published their work, and Schwinger never did.

Zierler:

So then how did you become aware of the Feynman diagrams?

Finkelstein:

I didn't need to use Feynman diagrams. I could get reliable results without using the Feynman. Then some years later, Jack Steinberger repeated my calculations with the Feynman diagrams, and they were quite in agreement.

Zierler:

What was the project you were working on that showed that your calculations were in accord with the diagrams?

Finkelstein:

These were for the instability of neutral pions. There are charged pions and neutral pions.

Zierler:

When did you begin at UCLA and what persuaded you to take that opportunity?

Finkelstein:

The reason I came to California was not to go to UCLA. It was to go to Caltech. Oppenheimer got me a job at Caltech, working with Bob Christian. I was a senior fellow at Caltech. And it was apparently Oppenheimer’s idea that that’s where he would put me—at Caltech. But while I was at Caltech, I enjoyed giving courses at UCLA, and David Saxon encouraged me to switch. Which was a normal thing, where—there wasn’t much going on at—Caltech was not as big, at that time. It had a big future, but David Saxon told me, “So does UCLA.” For me, it wasn’t a bad choice. Because then Feynman came to Caltech, and I certainly wasn’t going to be competing with Feynman.

Zierler:

You had a front seat both to Feynman and Schwinger. How would you describe their respective styles? Who was more impactful? Who has left the larger legacy?

Finkelstein:

Well, they were both wonderful lecturers. Schwinger was deeper.

Zierler:

You said deeper?

Finkelstein:

Feynman was enormously clever, but Schwinger was deeper. [laugh]

Zierler:

What does that mean? How was he deeper?

Finkelstein:

The way he solved problems was within a larger context than Feynman. Feynman’s context was narrower. And I would say the wide context, I call that deeper.

Zierler:

Is that to say that Schwinger left a larger legacy in physics?

Finkelstein:

Yeah, I think he did. He did, although the contribution that Feynman made was also very practical. Schwinger left a larger legacy, yes. That is true.

Zierler:

I've often heard it said that Schwinger was difficult to understand. Feynman was very accessible, but Schwinger was difficult to understand. Was that your experience?

Finkelstein:

I don’t know. They were both not very accessible. They both—because they had so many students, or people who wanted to work with them, it was hard to succinctly get to them. Schwinger carried a lot of baggage with him. You had to know a lot in order to follow. Feynman, you didn't have to know so much, but you had to be sharp enough to follow him.

Zierler:

Now, I'll still ask the question—when actually did you arrive at UCLA? I know the idea was to go to Caltech first, but then when did you switch over to UCLA?

Finkelstein:

Oh. I think after a year?

Zierler:

And how did that opportunity come about? Did they recruit you? Did you apply for an open position? How did that come about to come to UCLA?

Finkelstein:

I was giving courses there. So it was purely my decision.

Zierler:

Who invited you? Dave Saxon?

Finkelstein:

Yeah.

Zierler:

What was your sense of the UCLA department at that time? Were they already a well-established physics department, or were they looking to build and you were one of the hires toward that effort?

Finkelstein:

It was pretty good, and it was getting better. And that was before Schwinger had come. It was before Sakurai had come. So we were adding good people.

Zierler:

Was there always a competition with Berkeley? Was UCLA physics looking to compete with Berkeley at that time, perhaps as an upstart compared to Berkeley?

Finkelstein:

Of course. But in the early days, we weren’t doing so well. On the other hand, on my hundredth birthday, Harold Ticho, who had come also from Chicago and worked on cosmic rays, he wrote a nice note to me in which he said that he remembers a time when these people—I think there were five of us—came to a place which didn't have much of a reputation, and made something of it. And I think that’s pretty correct. Our first appointments were very good, and the later ones were, too.

Zierler:

How did your proposal of a unitary field theory come about?

Finkelstein:

It came about in various ways. For me, it was always suggested by the data. Not deeper than that. I mean, if—when you look at particles from a theoretician’s point of view—if you look at symmetries that these things require, I mean, the reactions don’t take place unless certain symmetries are observed. And one of the nice things that I found when I started working for Oppenheimer and I applied these new techniques to calculations of beta decay for weak interactions, they started to apply our new models to the weak interactions, beta interactions. What I found was, for example, that certain symmetries were not clear before I started the calculation, but in order to finish the calculation, you had to adopt certain new symmetries.

And so this was dramatic in my first work with Oppenheimer, we found that there were two unknowns—the coupling constants for beta decay, and the coupling constants are two of them. And both of them could be one way or the other. And both of them came out right. And then years later, parity violation was discovered. And parity violation required another restriction on our original model which also came out right. So we were agreeing with experiment That’s our test. That’s the only real test. When you ask about a unitary field theory, it means that the only thing nature gives us is if you make certain assumptions about the symmetry of the field and you do calculations observing these symmetries, they better come out right.

Zierler:

So you said that the unitary field theory relied on the data. It started with the data and your fealty to the data. So my question is, where did the data come from? Were you working with experimentalists? Were you running your own experiments? Where did the data come from that you used to create or to contribute to the unitary field theory?

Finkelstein:

When you set up a theory for calculation like we're describing, you have to assume a Lagrangian. Lagrangian means you have to choose differential equation. The kind of differential equation depends on the symmetries that you insert. There are general assumptions [symmetries] and specific assumptions [charges, masses, etc]. And you make assumptions of both kinds, as a rule. And they’ve all got to agree, and if they mostly agree and not entirely, then you look at that more carefully, and you make it a better theory.

Zierler:

So the next question is—I asked the same question about your time at Harvard, but maybe now it’s a little more relevant—when you were thinking in these years about the unitary field theory, did this lead you to consider that it might be a part of or it might yield new information leading to a grand unified theory?

Finkelstein:

No. I acted with a belief that one side of the grand unified theory was preferable to the other side I had examined. But my point of view was there was always room for improvement. These are very complicated things

Zierler:

Can we talk about supergravity? Let’s talk about where supergravity came from.

Finkelstein:

Supergravity is a theory which many people have proposed, including us. I had two papers on supergravity, and they came later than the Ferarra, Freedman, and van Niewhausen theory. But the argument was different. The theory was different. But they’re all supergravity. And Schwinger had also proposed the supergravity. So I think putting so much emphasis on the word “super” and supergravity—I don’t think that’s a good idea.

Zierler:

Why is that not a good idea?

Finkelstein:

Well, if you want to get grants, it’s probably a good idea. It’s not a good idea, because there isn’t a real scientific basis for it. It’s sort of a buzzword.

Zierler:

[laugh]

Finkelstein:

Oh. It’s a lot of hard work that goes into it.

Zierler:

What research have you been involved in, in recent decades? Since becoming emeritus, basically.

Finkelstein:

I would say improvement of the standard model. The standard model has undergone a lot of change. It has been successful (but we can still improve it). There are new things coming up all of the time. And what we find is that some of the new things are not easily accommodated by the standard model, and suggest going into a different standard model. And I have been studying a new standard model. And you can call that a new approach. My idea is that the standard model that has been used up until now is rather rigid. There are not many changes you can make in it. But there’s one kind of change that hasn’t been made, and can be made, and the last thing that I proposed is a standard model in which the elementary particles are knotted. It has the structure of knots. This is a new kind of symmetry. You would think that the knot idea is so simple, it would appear very early. But apparently it hasn’t in full force.

Zierler:

When you say a new standard model, is that to mean that it improves on the prior standard model, or it replaces the old standard model?

Finkelstein:

Improves. Or you could use the other word, too.

Zierler:

Or replace. Improve or replace.

Finkelstein:

It allows a new set of reactions which seem to be satisfied. And in that sense, it certainly improves.

Zierler:

Who have been some of your main collaborators on the new standard model? Are you working on your own, or are you working with partners in developing the new standard model?

Finkelstein:

It hasn’t been fully developed. I’ve been working on it [the knot model] for several years and sending drafts to Jan Smit, Cristina Cadavid and Ernest Abers and getting feedback from all of them. It’s published in a book, a book devoted to Schwinger [the centennial volume], and it has also appeared in ArXivs. It looks promising as far as I've gone. But—

Zierler:

Let’s stay on that for a second. When you say it looks promising, what do you hope to achieve with the new standard model? You say the new standard model looks promising. You're getting positive feedback from your collaborators. What do you hope to achieve with the new standard model?

Finkelstein:

Well, it’s a simple extension of what was there. It allows new reactions to take place that weren’t allowed before. Unfortunately, the new standard model allows a new set of reactions which have not been fully investigated. I can point out to you the reactions that it allows and that weren’t allowed before. That’s already in the paper. How far this extension will reach, I don’t know. I'm sure that it’s new, and there obviously are things here which we should know about, but it’s not clear at what point there is a problem. Because with every new theory, there is always a problem. So it’s really an unfair question to try to pin the fate on a new idea, on a model, which can’t be tested yet.

Zierler:

Let’s go on now. I want to ask, among your primary contributions, is there anyone that stands out? Over your 70-plus years in physics, is there one contribution that stands out, that you think is most significant? And if you don’t want to think of just one, I’d love to hear just generally what you see as your primary contributions to physics. Lots of people have ideas about how to answer this question for you, if you don’t want to choose yourself.

Finkelstein:

No, I can’t answer that. I mean, there were things that happened in theory, early theory which I could have pointed to at the time. And which I did. But all of these theories have a lifetime. So of these questions, which are you aiming at?

Zierler:

What is understood in physics now that was not 70 years ago, and what remains mysterious?

Finkelstein:

Hmm. So much is understood now, especially about the cosmos. About the structure of the universe. All of these things are pretty solid now. Is it easier to put such a question in a biological context?

Finkelstein:

Now here in physics, so much is new. It is new, but we don’t know enough about it. I'm saying that while we're waiting for another big discovery, that we shouldn't throw away what we've learned so far. We've learned an awful lot. I remember when Schrödinger's book came out, many of the physicists were saying that he’s going too far. Dirac said that we can understand chemistry by quantum mechanics in that period, and then the corresponding statements began to come out about biology. People were much slower, because it was a more difficult problem. You know what I'm saying?

Zierler:

What has been your style as a mentor? Who have been some of your most significant students?

Finkelstein:

I would say we work on things together. When we come to a new field, there are questions in the field. I don’t care who works on what, as long as there’s progress, and there just needs to be continual progress.

Finkelstein:

I think the individual students choose their own questions. I think MalRuderman has probably made the biggest name. Jan Smit. Steve Gasiorowicz, and AlbertoSirlin.

Zierler:

Last question. What are some of the most exciting opportunities for the future of physics? Will it ever be possible to resolve all paradoxes, and what will it mean if we do?

Finkelstein:

[laugh] I wouldn't be hopeful about that. I mean, here, it really gets vague.

Zierler:

We could start with the first part. What are some of the most exciting opportunities for the future of physics?

Finkelstein:

I don’t know. [laugh] If you have any modesty at all, at a certain point you have to stop this.

Zierler:

Well, Robert, thank you very much.

[End]