Robert Jaffe

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ORAL HISTORIES

Credit: Justin Knight

Interviewed by
David Zierler
Location
Video conference
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Interview of Robert Jaffe by David Zierler on April 24, 2020,Niels Bohr Library & Archives, American Institute of Physics,College Park, MD USA,www.aip.org/history-programs/niels-bohr-library/oral-histories/44398

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Abstract

In this interview, David Zierler, Oral Historian for AIP, interviews Robert Jaffe, Morningstar Professor of Science at MIT. Jaffe recounts his childhood in Connecticut and his early interest in natural history and his advanced chemistry education in high school. Jaffe described his undergraduate education at Princeton where he developed his interests in both physics and social justice issues. Jaffe describes his formative summer in Europe in 1968 and his decision to pursue his graduate work at Stanford. Jaffe explains the formative role of Sid Drell and SLAC in developing his dissertation on the difference between the parton model and the current algebra approach to deep inelastic physics. Jaffe describes his initial attraction to join MIT, which he felt was uniquely egalitarian, and his development as a professor there over the course of his career. Jaffe describes his advisory work at Brookhaven Lab, and his more recent interests in the physics of energy. Toward the end of the interview, Jaffe reflects on why he believes theoretical physics is the natural domain of younger scholars, and what he considers to be his primary contributions to the field.

Transcript

Zierler:

This is David Zierler, oral historian for the American Institute of Physics. It is April 24th, 2020. It is my great pleasure to be here virtually with Professor Robert Jaffe. Professor Jaffe, thank you very much for being with me today.

Jaffe:

My pleasure. Thank you.

Zierler:

OK, so let’s start with your title and institutional affiliation.

Jaffe:

I am the Morningstar Professor of Science at MIT.

Zierler:

Let’s start right at the beginning. Tell me about your birthplace and your family and your early childhood.

Jaffe:

I was born in Bath, Maine, in the year directly after World War II. In fact, strategically, I was born nine months after the end of World War II.

Zierler:

[laugh]

Jaffe:

My parents had moved to Bath, Maine, early in the war. My father owned a small clothing store. My mother was a housekeeper. And they moved to Bath in an opportunity for engaging in a thriving community, because Bath was the home of a major shipbuilding facility, the Bath Iron Works. And my brother and I were both born there, and when the war was over and Bath went into an economic decline, as it often did, my parents moved to Connecticut.

Zierler:

Where were your parents from?

Jaffe:

Both my parents were born in the United States. Their families had moved to the United States—my mother’s in the late 19th century, and my father’s family in the early 20th century. My father was born in Ohio, and my mother was born in New York. They both grew up more or less in the time of the Depression, and neither of them went to university. My father started at the University of Akron and had to leave for financial reasons. My mother did two years at an art school in New York. She was an artist.

Zierler:

Do you have the sense that with better opportunities, your father would have continued with his education?

Jaffe:

I think he certainly would have. He was really forced out of his trajectory by the economic hard times.

Zierler:

Did you do public school throughout your childhood?

Jaffe:

I did. I was very fortunate. I was in Stamford, Connecticut, which was a bedroom community of New York, and it had an extremely well-supported and excellent public school system. In particular, the high school I went to was brand new and was staffed by many young and ambitious educators who now would have been considered real outliers in high school education.

Zierler:

When did you start exhibiting a strong aptitude in math and science?

Jaffe:

Probably way back at the beginning. As a small child, I was more of a natural history fanatic than I was a mathematical puzzle solver. I think that has kind of defined my style in physics all along. I was interested in geology and paleontology, in butterflies and natural phenomena. I think I was captured by scientific education in high school when I had an extraordinarily talented high school chemistry teacher and spent much of my high school years in her lab, in the back rooms of the chemistry department.

Zierler:

Do you remember your chemistry teacher’s name?

Jaffe:

Yeah, her name was Sarah Anne Cassaday and she was a Yale PhD who married another chemist who had some kind of physical disability, and she was forced to go back to work as a young woman. She was the head of the science department at the high school.

Zierler:

Oh, wow.

Jaffe:

The physics teacher, by the way, was terrible. [laugh]

Zierler:

[laugh] When you were thinking about majors for college, did you think chemistry before physics?

Jaffe:

Well, I also did very well in the humanities. I had quite an excellent teacher in high school English, and in social science. And so I was a very broad kind of intellectual in high school. And these were unusual times. There was a guidance counselor in high school—I didn't come from the world’s most sophisticated background --- the guidance counselor said to me at some point, and I will never forget, that engineering is the union of the sciences and the arts.

Zierler:

Huh.

Jaffe:

Which I've come to look at with a kind of jaundiced view, I have to say. And so I started out as a chemical engineer. And I went to a university that I thought had the best science and liberal arts that I could find, that still had an engineering school, and that was Princeton, which was very fortunate.

Zierler:

What other schools did you apply to?

Jaffe:

Tufts.

Zierler:

Just two?

Jaffe:

Yeah.

Zierler:

Because of that very unique background you were looking for?

Jaffe:

No, I think I was overconfident. [laugh]

Zierler:

[laugh] Well, it worked out!

Jaffe:

It did, yeah.

Zierler:

So you had that declared major at the beginning. When did you switch over to physics?

Jaffe:

Because I had had such extraordinary background in chemistry in high school—I had taken two years of college chemistry in high school—I placed into a junior year physical chemistry course when I was a freshman. That was taught by a now I recognize very famous physical chemist named Walter Kauzmann. And I loved it. And the chemical engineering course I was taking was not very challenging. And I was also taking the mainstream physics course, not the high-level physics course but the introductory freshman calculus-based mechanics and electrodynamics course. And I was quite unhappy with being an engineering major, quite enthralled by the physical chemistry course. But I happened to have a recitation instructor, an instructor in the physics course, whose name was Gerry Garvey, who was really my first mentor in physics. He was a young associate professor working in experimental nuclear physics on fundamental symmetries. And he took me aside one day and asked me what my major was, or what I was doing. And I told him that I was majoring in chemical engineering, and that I was enjoying the physical chemistry course, and I told him about that course. And he kind of skewered me with the statement that actually what I was enjoying about that course was physics, and that in essence the physical chemistry course was a broad introduction to the corpus of more or less fundamental physics from a solution-based point of view—thermodynamics in solution, statistical physics in solutions, and quantum mechanics as it pertained to reactions in the chemical world.

Zierler:

Was he making that comment about physical chemistry generally, or specifically about what he saw in terms of your aptitude?

Jaffe:

Well, I think he was trying to sell me on physics. [laugh]

Zierler:

[laugh]

Jaffe:

Which was a good thing. He offered me a summer job that summer. I guess I may be getting the years confused, because it was the summer after my sophomore year that I worked with Gerry’s group.

Zierler:

This would have been the summer of ’65?

Jaffe:

No, that was the summer after my freshman year. I started college in the Fall of ’64, so it was the summer of ’66. And he offered me a job as a part-time operator on the Princeton cyclotron, which was a 1938 vintage cyclotron in the basement of the old Palmer Physics Lab. And in those days, an undergraduate could be the sole operator on the night shift from 11:00 at night until 7:00 in the morning.

Zierler:

Wow. Was that your shift?

Jaffe:

That was what I did, for quite a bit of the time. I did the day shift sometimes, too. But I also managed to destroy some apparatus, which is a kind of cute story. My job was to take data at various angles in the scattering experiment, and when the scaler had indicated that the number of counts was up to the statistical level that was needed—roughly 100,000 counts—my job was to shut down the cyclotron, wait until radiation levels were safe, and then move the detector from one place to another in the scattering chamber. And one time shortly after I moved it, a safety system was triggered. All the lights flashed. The machine shut down. And when the radiation had subsided, I went up and looked and saw that the methanol line that was used to cool the detectors had popped off the back of one of the detectors and leaked into the scattering chamber and flooded it.

Zierler:

Oh, boy. This sounds like a scene out of a movie

Jaffe:

It was a lesson not to become an experimental physicist.

Zierler:

[laugh]

Jaffe:

So although I did continue part-time as an operator, I was asked—I was seconded to the theory group to help with some analysis of the data.

Zierler:

Aha. So you didn't get in trouble so much as they said, “You might want to focus on other things.”

Jaffe:

Yeah, well, Gerry insisted that I had been instructed not to move the detector past 135°, but I had no recollection of that. I think they jokingly said I destroyed about $10,000 worth of new lithium-drifted germanium detectors. I don’t know whether that was true or not.

Zierler:

[laugh] When did you actually declare the major in physics? Was it your sophomore year?

Jaffe:

Yeah, I was already a physics major in my sophomore year. When I entered Princeton I was selected for a program called the University Scholars Program. Princeton admitted about 20 students into a special program where they had private advisors and no requirements. So I had no graduation requirements whatsoever. I took whatever courses I wanted to. So I took courses in architecture, in economics, and literature, and history, and lots of physics and math courses.

Zierler:

Oh, wow. That’s a very unique sort of course of study for most physicists, to have that broad a base of education as an undergraduate.

Jaffe:

Yeah, it was a real pleasure to be able to do that. Made a difference.

Zierler:

I don’t know from your vantage point as an undergraduate, but what was your sense in the physics department in terms of trends, in terms of the things that were being prioritized, in terms of the possible hierarchy of where the experiments were vis a vis the theorists? What was your sense of all of those things as an undergraduate?

Jaffe:

I think the Princeton physics department was dominated by two trends in theory. One was mathematical physics, which was the domain of Arthur Wightman and Valentine Bargmann and Eugene Wigner who was just about to retire.

Zierler:

Was he still taking students at that point?

Jaffe:

Not that I know of. There was the relativity group with John Wheeler and Jim Peebles, who taught me undergraduate statistical mechanics, actually, so I knew Peebles fairly well. And then there was the particle physics axis, which was dominated by Murph Goldberger and Sam Treiman, who were just beginning to glimpse some kind of vision of what elementary particles really were. So they were moving beyond dispersion theory, which was a kind of general formulation based on general principles that had no fundamental dynamical principle—you probably have talked with people about Geoff Chew’s vision of particle physics which dominated the ‘50s and early ‘60s. And Goldberger and Treiman were starting to derive some rules and relations that abstracted from the algebra of the currents in quantum field theory. So that was a very dynamic group. Nevertheless, I wasn’t part of either of those traditions. I was working with the nuclear physics group. Princeton had a very strong tradition in nuclear physics that had suffered as Wigner had become less active, and the department had hired a nuclear physicist, a distinguished nuclear physicist named Gerald Brown. Gerry Brown. And Gerry Brown was really the person who organized the group that I did most of my undergraduate research with. But I got very strongly involved in research very early with that group.

Zierler:

Was your sense that in bringing Brown on, that Princeton was trying to revive nuclear physics?

Jaffe:

They were, and it wasn’t a good match. Brown was much more politically radical than the physics or university faculty. He had been forced to leave the country during the McCarthy era, had done his important work in Denmark and in England, had come back, and found himself uncomfortable in the kind of staid atmosphere at Princeton. But he had a strong group around him. He had visitors and young postdocs –Akito Arima, Harry Lipkin, Tom Kuo, Tony Green, --- I remember visits from Ben Mottleson and Aage Bohr --- and they were very interested in working with undergraduates. One of the attractions for undergraduates of theoretical nuclear physics is that it doesn't require quantum field theory. Or at least in those days it didn't. [laugh] So it was possible to do useful and important and educationally relevant research in nuclear physics at a much earlier stage in one’s career.

Zierler:

Now, did you come to appreciate these tensions that Brown felt with the department later on, or were you aware of them at the time?

Jaffe:

Oh, I liked everybody in the department. [laugh] I thought it was a great time.

Zierler:

I mean in terms of your comments about the poor fit between Brown and the political atmosphere at Princeton.

Jaffe:

Oh, I think Brown was quite vocal about it. I was friendly with him and his wife, went to parties in their house from time to time, evening seminars, discussions. And the discussion turned to politics as often as it did to physics.

Zierler:

And is this where your own interest in political and social justice issues really took off, or you were interested in these things beforehand as well?

Jaffe:

I was interested beforehand, and I also thought Brown’s point of view was too orthodox on the side of sympathy with the Soviet Union, frankly. I think Gerry’s wife was a communist, and she was not happy living in the United States. She favored the “great socialist endeavor” of the Soviet Union, and that was not what interested me.

Zierler:

That was a bit too much for you.

Jaffe:

But I was involved in the undergraduate intellectual world in which criticism of the American position on the Vietnam War and social justice issues were becoming very important.

Zierler:

Now, by the time you graduated in 1968, what was the environment on campus like? Were there protests already, or you had left before that really started?

Jaffe:

It was on the cusp. There had been some involvement in the Civil Rights Movement, which I wasn’t terribly involved with. But the protests that were erupting in Berkeley and in Columbia were just beginning to have an impact around Princeton. And then of course in 1968, things broke open in a catastrophic way with the assassinations of Martin Luther King and Robert Kennedy.

Zierler:

Right. But your sense was that Princeton was not really leading those things? It was sort of more generally aware of what was going on elsewhere, and perhaps was reactive to that?

Jaffe:

I think the first demonstrations at Princeton against the Institute for Defense Analysis, which was on the Princeton campus, were in 1968. I wasn’t involved in those. Instead I was writing letters to my senators with other undergraduates from Connecticut, helping to encourage them to protest the war and things like that.

Zierler:

Did you have a senior thesis?

Jaffe:

I did. I did three undergraduate research projects. The senior thesis was on nuclear scattering theory, working very closely with a young postdoc in Gerry Brown’s group named Bill Gerace, who mentored several undergraduates who have gone on to distinguished scientific careers. It was at that time that I met Alan Lightman, another protégé of Gerace, who became a lifelong friend. Gerace went on to teach at the University of Massachusetts for many years.

Zierler:

And was he the one who gave you the problem to work on, or you came up with it on your own, mostly?

Jaffe:

That’s a good question. I think it grew out of the analysis of the experiments that were going on at Princeton, which were called two-nucleon transfer reactions. The question was, what was a good dynamical model for the mechanism for the scattering process in which an incoming proton reacted with a nucleus leading to an outgoing triton or helium-3. So picking up a deuteron out of the nucleus or picking up two neutrons out of the nucleus. The models that were being advocated were very primitive, and I found it relatively easy to construct a model that respected energy conservation and quantum mechanics. It fit data well too.

Zierler:

Did you publish the thesis?

Jaffe:

I did. Gerace and I published a paper on that work—it was my third paper, and it was a good paper.

Zierler:

I assume at this point you were on a momentum where going straight to graduate school was a definite. You really were not considering another path or taking time off before graduate school?

Jaffe:

Yeah, well, there were reasons for that politically. If I took time off, I had to deal with the draft. Although by the time it had come to making a graduate student decision, I had already received a deferment for my eyesight, which is lousy. I had a draft physical in 1968 and was deferred. But yeah, at that point, the idea of going to graduate school was very exciting. And in fact, the transition to graduate school was made particularly easy because Brown arranged me to spend the summer of 1968 in Copenhagen at the Niels Bohr Institute.

Zierler:

How was that experience?

Jaffe:

Fantastic. Both the physics was exciting—I met all kinds of young physicists. I again met Aage Bohr and Ben Mottelson. But I also spent a lot of time traveling around Europe during the summer of 1968. I was in Paris during the Bastille Day riots in Paris.

Zierler:

Wow! [laugh]

Jaffe:

It was quite a time.

Zierler:

Were you part of a program in Copenhagen of American students, or this was just a solo mission on your part?

Jaffe:

Yeah, it was just Gerry Brown was in the habit of sending his favorite students to Copenhagen, especially if they had spent four years as an undergraduate in an all-male institution like Princeton.

Zierler:

Were you involved in projects there, or it was more like attending seminars and things like that?

Jaffe:

Yeah, I wasn’t integrated into any particular group. I was working on publishing my thesis. I was working on writing up my valedictorian speech. I was working on another paper with Gerry Garvey on nuclear mass relations. And I was reading quantum field theory.

Zierler:

It’s a good place to read quantum field theory. [laugh]

Jaffe:

Yeah. It was a great place.

Zierler:

What did you choose to focus on in your valedictorian speech?

Jaffe:

Student activism.

Zierler:

You didn't touch on sciences?

Jaffe:

Hardly at all.

Zierler:

Interesting, interesting.

Jaffe:

I didn't think—you know, this was—Bobby Kennedy had been assassinated days before I gave my speech, and Columbia was in flames. It was a time to talk about the role of students in reshaping a society.

Zierler:

Did it have an optimistic tone to it?

Jaffe:

Mixed. I felt that the direction of student activism was too anti-institutional, and it was alienating citizens from the broader culture, whom they had to try to influence in a positive way.

Zierler:

And were you thinking of student activism at Princeton in general, or were you making a sort of broader point about student activism in America?

Jaffe:

More broadly about the student activism across the country. I called attention to the problems at Columbia and advocated for a less institutional, more integrated form of engagement with the broader society.

Zierler:

When it came time to think about graduate programs, what was your decision-making process?

Jaffe:

Largely based on people and weather.

Zierler:

[laugh]

Jaffe:

I had good advice that Stanford had a really excellent program shaped around the newly commissioned accelerator center at SLAC, and that Sid Drell was a particularly good person to work with. I also was considering Harvard, because Shelly Glashow had just come to Harvard, and it was thought that he might be a really good person to work with. And so I applied to Stanford and Harvard. And then later on—there was a general rule at Princeton that they didn't accept their own students --- but late in the process, they offered me a graduate position at Princeton as well.

Zierler:

Was that tantalizing to you, or you had enough of Princeton at that point?

Jaffe:

I think it really was the weather. It was a lousy spring in Princeton. It was rainy. It was cold. And the idea of going to California in 1968 was a very exciting idea.

Zierler:

Now when you mentioned with Shelly that he was known to be a very good person to work with, is that specifically referring to his reputation as a mentor to other graduate students, or in terms of the kind of projects that he was working on, or both?

Jaffe:

I think it was mostly the kind of projects he was working on. I think in retrospect, Shelly would not have made a good thesis advisor for me. I think Sidney Coleman would have been a much better thesis advisor, and had I gone to Harvard, I probably would have gravitated towards Sidney rather than Shelly.

Zierler:

And what was Shelly working on, at that time?

Jaffe:

Current algebra and SU(3) symmetry and hadronic mass relations. Actually hadronic mass relations and electromagnetic mass differences. So people were beginning to use the tools of quantum field theory in a generic as way as possible to try to explore the inner structure of strongly interacting particles. So the Coleman-Glashow relation for baryon masses, the electromagnetic mass sum rules, were beginning to suggest that there was some underlying structure that you would probe in hadrons.

Zierler:

That answered my question. So at Stanford, were there particular people that you were interested in working with, or general projects that you wanted to be a part of?

Jaffe:

I think I was shepherded to—I think Murph Goldberg and Gerry Brown basically sent me to Stanford to work with Sid Drell.

Zierler:

And so were you there in the summer before, or you got there right there in the Fall of ’68?

Jaffe:

I arrived in mid-August of 1968.

Zierler:

So what was the scene like? What was going on, on campus, then?

Jaffe:

[laugh] It’s all a blur to me. I was trying to find a place to live in. I had a new girlfriend. The politics were eruptive around the country. I missed the Chicago Democratic Convention, but the election was coming up. I was working with groups of people on trying—at first to get Gene McCarthy nominated—I guess that was before the Convention—but trying to prevent the election of Richard Nixon. I was trying to settle into a new department. I was learning that the department was not eager to have its students get engaged at SLAC.

Zierler:

Oh, I had not heard that. What was the reasoning there, as far as you knew?

Jaffe:

Well, I learned over the years that there was a longstanding animosity between the theory group at Stanford and the theory group at SLAC that had developed during the rupture that led to the formation of SLAC.

Zierler:

So with graduate students, was the concern that they were going to get in the middle of that?

Jaffe:

Well, the graduate students were not allowed to have their advisors from the SLAC faculty until at least their second if not third year.

Zierler:

Interesting.

Jaffe:

So I was originally advised by Leonard Schiff in the Stanford Physics Department.

Zierler:

Once you got your bearings and you understood how things worked in the physics department there, what were some of the basic differences that you saw between physics at Princeton and physics at Stanford?

Jaffe:

Two things. First of all, mathematical physics held a back seat at Stanford. The atmosphere at Princeton, going back a little bit, was strongly dominated by Wightman and his students. The common room in the Fine Library in the attic of the math building at Princeton was the place where I and other hardworking physics majors hung out with the theory graduate students. Barry Simon, who is now a very distinguished mathematical physicist, was then a graduate student, and he and other Wightman students really dominated the atmosphere and philosophy. In truth I found that area of mathematical physics rather sterile. And I was very happy that at Stanford, the theoretical effort was more based on the application of mathematics to the phenomena that were observed in the real world. And that was true both on the campus and at SLAC.

Zierler:

Who were some of the faculty members who were really driving that trend?

Jaffe:

At Stanford?

Zierler:

Yeah.

Jaffe:

Well, certainly Leonard Schiff in quantum mechanics and general relativity, and Dirk Walecka in nuclear theory. Sandy Fetter in condensed matter physics. Felix Bloch was by then probably retired, but still had an important influence on the campus. Another difference between Princeton and Stanford was also a struggle between Stanford and Berkeley. There was no analogous tension at Princeton. , That was the struggle of field theory versus the—I don’t know what you want to call it—the bootstrap, the Chewvian philosophy of fundamental physics. And Stanford was a place where field theory was appreciated and its power in understanding the physics of particles was beginning to emerge. And that was true on the campus as well as at SLAC, although I think SLAC was really the center of that physics. Bjorken and Drell and Fred Gilman and Stan Brodsky were all working away with great excitement at SLAC.

Zierler:

How much of the graduate education was coursework?

Jaffe:

Not much. There were a few required—of course, I didn't take many courses in the physics department. I took more courses in the math department. There was a wonderful mathematician named Menahem Schiffer in the Stanford math department who taught a range of graduate courses on complex analysis, potential theory, integral equations, general relativity. Schiffer wrote the first textbook on general relativity that was widely used, with Ron Adler, and Maurice Bazin. Adler, Bazin, and Schiffer was the standard textbook in general relativity at the time. And Schiffer’s courses were terrific, and a strong influence on me in the application of classical mathematical analysis to theoretical physics problems.

Zierler:

And this was your own idea, to sort of gravitate towards the offerings in the mathematical department? Or you had faculty who were advising you in that direction?

Jaffe:

I literally don’t remember. I think the strength of Schiffer’s courses was generally strongly appreciated by the theory graduate students and many of them, like me, enrolled in Schiffer’s courses. I did take courses in the physics department, but not too many.

Zierler:

At what point did you develop the Workshop on Political and Social Issues?

Jaffe:

Oh, that grew out of the March 4th movement, which was the movement of scientists and engineers against the war, culminating in a day of protest and teach-ins on March 4th, 1969. I got involved in planning that event in part through Marty Perl, the experimental physicist at SLAC who won a Nobel Prize for discovering the tau lepton. Marty was a very generous soul and a very eager leader in trying to mobilize science and engineering research and influence in government against the Vietnam War.

Zierler:

And the March 4th movement was specific to Stanford, or other campuses were involved in this, also?

Jaffe:

To my recollection, it was dominated by MIT and Stanford and Cornell. The ideas that led eventually to the Union of Concerned Scientists, for example, grew out of the March 4th movement.

Zierler:

Oh, interesting!

Jaffe:

So Henry Kendall, Kurt Gottfried, they were leaders in this March 4th movement.

Zierler:

Do you remember or did you have a sense of where this start…like who started it, or what campus, and then who followed?

Jaffe:

I think it started at MIT. I think maybe Phil Morrison, Viki Weisskopf, and Francis Low were involved in it also, but Henry Kendall was a very strong player. And Henry was doing the experiments at SLAC that led to the discovery of quarks. There was a strong connection between MIT and SLAC at that time. And I made friends with another physics graduate student, Joel Primack, who had been a Princeton undergraduate, and I was involved in some active anti-war protests which brought me into contact with some leaders in the undergraduate community. We decided to start this program on our own—this Stanford Workshops on Political and Social Issues.

Zierler:

And what was March 4th? What was the March 4th in the March 4th movement?

Jaffe:

Well, March 4th was a daylong teach-in on the campus, and it was structured, I think unfortunately, as a debate between advocates pro and against the Vietnam War. And I don’t think it was as successful as it might have been because it ended up with a lot of people yelling at each other.

Zierler:

Now, did you feel the influence of Department of Defense funded initiatives at Stanford? Were there things that were obvious to be upset at, in terms of military funded research? Or was there more a broader conceptual issue?

Jaffe:

Oh, there was a direct focus on military research on campus. There was classified research at a laboratory called the Applied Electronics Laboratory, and there was a research institute called SRI, the Stanford Research Institute—that had on-campus presence and was doing classified war research. The student movements at Stanford were, among other things, eliminating classified research from campus. I was more interested in redirecting such research toward benefits to humankind.

Zierler:

To the extent that you can unspool one from the other, how much of the protest was about anti-Vietnam War sentiment in particular, and how much was it just the Department of Defense should just not be involved in what we're doing here, generally?

Jaffe:

Don’t know. Most of the focus was on anti-war research, anti-war protests. But my focus by that time was on building this program, which was much broader, and interested in how scientific expertise could be used to inform the government and help the society.

Zierler:

Did you see a positive role for military and higher education research partnership? Or did you think that generally, those two worlds should be separate?

Jaffe:

To the extent I thought about it, I thought they should be separate.

Zierler:

OK, so what was the process that led to your dissertation topic? How did you come to that topic?

Jaffe:

I think I imbibed it out of the atmosphere at SLAC. When I arrived at SLAC, Sid Drell, although he was a wonderful mentor and friend, was deeply involved in advising in Washington. He was very actively involved in an early project on partons with Tung-Mow Yan, who is now at Cornell. That was his main research activity, but I think it was driven mostly by Tung-Mow. And I was more strongly influenced by the younger people at SLAC, who were caught up in trying to understand what the results on deep inelastic electron scattering were telling us about the substructure of hadrons. There was a revolution going on in our understanding of particle physics. When I was an undergraduate, nobody had the slightest idea what a proton was. It was some kind of extended object. It was not understood whether it was fundamental or composite or what. The SLAC experiments could understood in terms of an algebraic substructure by the approach that was dominated by Murray Gell-Mann. On the other hand, they could be understood in terms of some kind of particle substructure by the approach that was dominated by Bjorken and Feynman. And I was really strongly swept up and excited by the prospect of trying to unify that picture and exploit it to understand the structure of protons, neutrons, and their friends in the context of quantum field theory. So I was not assigned a thesis topic. My thesis topic grew out of my own perception of the problems at the time.

Zierler:

And were you sort of chomping at the bit to get over to SLAC? You mentioned earlier that that was not available to younger graduate students. Did you sort of gravitate there as soon as you could have?

Jaffe:

Yes. I went out there and met Sid, and Sid offered me a desk in the theory graduate student area—I don’t know what to call it; it was like a play pen, a couple of big rooms with lots of desks.

Zierler:

Now these tensions that you mentioned earlier between the physics department and SLAC, was your sense that they were substantive in nature, or were these really just a matter of personalities?

Jaffe:

I think they were fundamentally a matter of personalities. Also, I think Stanford was not interested in the large-scale physics that SLAC was trying to initiate. Pief Panofsky had a vision that going to higher energies would be the informative way to reveal the substructure of hadrons. And Robert Hofstadter was very much focused on his own experiment program of low-energy transfer, which had—he was interested in measuring form factors, elastic and excitation form factors, which it turns out give limited information about hadron substructure compared to deep inelastic scattering, which because of its quasi-elastic nature, can probe much more deeply at short distances. It was not immediately appreciated at SLAC, how powerful deep inelastic scattering was, but it was an emerging idea that entirely bypassed the campus physics department.

Zierler:

Were there any bureaucratic challenges in terms of working within the SLAC environment but being a graduate student in the physics department, in terms of who could be on your committee or where you were drawing resources from? Or was that a smooth arrangement?

Jaffe:

It was smooth. Once you had an advisor at SLAC, that was all you needed, and the thesis committee was put together.

Zierler:

Who was on your thesis committee?

Jaffe:

Bjorken and Harold Levine, a mathematician (and former student of Julian Schwinger). So there was a mathematician on my thesis committee.

Zierler:

So just two?

Jaffe:

And Drell.

Zierler:

And Drell, OK. So what did you see as your primary contribution with the dissertation?

Jaffe:

My dissertation concerned establishing the relationship and the difference between the parton model and the current algebra approach to deep inelastic physics. Gell-Mann and his school was advocating this algebraic approach, which was called light-cone algebra and attributed deep inelastic phenomena to a fundamental algebraic structure of the currents that probe inside hadrons. And the commitment to particle substructure was avoided at all costs. You probably know the story—Murray regarded quarks with very divided loyalty, and he built his currents out of quark degrees of freedom, and then refused to admit the existence of quarks.

Zierler:

[laugh]

Jaffe:

So I had become a real expert in quark light-cone algebra, and I wrote some papers that had to do with Murray’s approach and light-cone algebra; a paper with Chris Llewellyn Smith, for example, who was a postdoc at SLAC at the time. But because SLAC was so strongly influenced by Bjorken and Feynman, I also knew all the structure of the parton model, and I proved analytically that the parton model and the current algebra approach were isomorphic for deep inelastic phenomena. They made the same predictions with essentially the same phenomena. They were simply related to each other by Fourier transforms. But I also showed that the phenomenon of mu-pair production, which is called the Drell-Yan process --- hadron-hadron collisions leading to a massive muon/anti-muon pair in the final state—this is now the process by which all heavy particles such as Higgs and W bosons are produced in colliders—and we now understand that as quark/antiquark or gluon/gluon annihilation into a heavy current mediator. I showed that that process is not light-cone dominated, that the current singularities that were so important to Gell-Mann’s algebraic process did not make any predictions about this process at all, but that the partonic interpretation naturally led to the dominance of these particular diagrams that led to the scaling of the cross-sections and to the copious production of heavy vector bosons in the final state.

And so there was a clear test of which picture had the lasting value for understanding hadron substructure. And the test was to see whether the Drell-Yan process was confirmed experimentally. And so I published—my thesis was glued together from three or four papers, but the primary impetus was the comparison between the parton model and the light cone algebra predictions for short distance behavior.

Zierler:

Now, I'm sure in the process of doing this research, you're very narrowly focused, as dissertation writers tend to be. But did you ever dwell then, or later on, about the impact of your work on broader questions about fundamental concepts in physics or how the universe works? Or you never explored those kinds of parameters?

Jaffe:

I don’t think I was thinking in that direction—I think the excitement of the times was—the times were so heady, we were so swept up in the excitement of understanding what hadrons were. It was really the forefront of a revolution.

Zierler:

What was the intellectual heritage of that question about what hadrons were? What was your sense of where that question came from, and who was asking the most important questions before your time?

Jaffe:

Well, I think it was the dominant intellectual confusion in fundamental physics of the 1950s. In the late 1940s, the picture of the strong interactions was relatively simple. There were protons, neutrons, and pions, and maybe people were beginning to understand K mesons, kaons. And that picture, which was fundamentally field-theoretic, based on Yukawa-like ideas, was falling apart in the 1950s as more and more hadronic resonances were discovered. There was a period of great confusion—

Zierler:

What did those discoveries do to the theory? What impact did they have exactly?

Jaffe:

Well, there was no field theoretic structure that could accommodate the multiplicity of excited states of the hadrons. For example, no one knew how to write down a field theory with spin-5/2 particles. Nobody knew how to extract anything interesting from field theories outside the framework of perturbation theory. And the strong interactions were clearly too strong to be treated perturbatively. Much of the community simply gave up on field theory, led by Geoff Chew, who was a very strong and charismatic advocate for a picture that in retrospect looks almost absurd: that you could write down fundamental constraints on a theory such as causality, maximal analyticity, and Lorentz invariance, and from those fundamental principles alone, deduce this incredible zoology and complexity of hadron structure. And field theory and advocates for field theory were out of favor and were struggling at that time. There were a few people, Steve Weinberg among them, who stuck with field theory all through that period. You're smiling like you've heard this from somebody before?

Zierler:

I have. Yeah, yeah.

Jaffe:

And there were others like Sam Treiman, who was a wonderful physicist, who maintained a foot in both camps. Maybe Murph Goldberger did to some extent, also. And the Stanford group, Sid Drell and his company, were still field theorists, fundamentally. Personally, I never understood Chew’s picture of the world. I found it distasteful. I felt like it had no fundamental predictive power. And so when the possibility of understanding strong interactions through a field theory emerged, it was an exciting and overwhelmingly compelling time. It felt like a revolution was going on at Stanford in those days.

Zierler:

When you said that it had no predictive power, what broader expectation, just in terms of science and discovery in general, are you applying here to make this criticism?

Jaffe:

Spectrum and interactions. In fact there was this incredibly rich spectrum of hadronic states—mesons and baryons, books full of resonances, interaction cross-sections that had all kinds of systematic structure. And the Chewian picture couldn't get beyond pi/pi scattering at low energies.

Zierler:

And did he have a ready-made response to this line of criticism?

Jaffe:

I think it was almost a compelling religious picture, that this was the only way to proceed, and we had to do what we could. And analyticity and unitarity had some triumphs in what was called Regge theory, a theory of high-energy reactions at low momentum transfer. Regge theory started out simple. With a few Regge trajectories, you could make some relatively compelling predictions about the high-energy behavior of charge exchange reactions, that they should fall like one over the square root of the center of mass energy. But then when you got to slightly more complicated situations, the Regge picture fell apart. Instead of one or two Regge poles, Regge cuts and “pomeron” interactions with reggeons. The whole thing proliferated into a picture that was unpredictive. And that was often what happened with the bootstrap picture. The wonderful thing about the field theoretic picture that emerged at SLAC was that it was incredibly predictive.

Zierler:

Now, when you defended, what were some of your options at that time? What was your plan? Did you want to stay at SLAC? Did you know that from the get-go? Or were there other options that you were considering?

Jaffe:

I didn't want to stay at SLAC. I had more or less had it with California at that point. And although I was offered a Miller Fellowship at Berkeley, I didn't want to go to Berkeley because of my distaste for the world of Geoff Chew.

Zierler:

When you say you had it with California, you just mean like culturally? The whole Northern California way of looking at the world?

Jaffe:

Yeah. I felt that the culture in California was too frivolous for my taste. [laugh]

Zierler:

[laugh] Did that creep into your physics experience as well, or are you talking more broadly just living in Northern California?

Jaffe:

No, I think it was living in Northern California. I think the physics at SLAC was terrific, and the style of physics dominated in those days by Bjorken and Gilman and to some extent Brodsky and the postdocs—by then I had formed collaborations and friendships with Chris Llewellyn Smith, John Ellis, Frank Close, Jack Gunion, David Broadhurst, and several others who passed through SLAC during those days. But none of them were staying in California. I felt that the opportunities to do physics on the East Coast were more exciting.

Zierler:

What were some of your options? What were you excited about pursuing?

Jaffe:

In terms of institutions?

Zierler:

Yeah, after SLAC. Did you know you wanted to go to MIT? Was that the obvious destination, or were there other options you were considering?

Jaffe:

Well, I had turned down an offer to be nominated for a junior fellowship at Harvard. I'm not saying I would have been chosen as a junior fellow at Harvard, but I turned it down because I wasn’t enamored of Harvard. I applied to Princeton, to the Institute for Advanced Study, and to MIT.

Zierler:

These were all postdoc opportunities?

Jaffe:

These were postdocs, yeah.

Zierler:

So when you said you weren’t happy with what was going on at Harvard, what do you mean by that?

Jaffe:

I had a longstanding—although I did apply there for graduate school, I had a longstanding distaste for Harvard dating back to high school. It’s an amusing story: When I was a high school senior in Stamford, Connecticut, or when I was a junior actually, the top performing junior was given a prize called the Harvard Prize, the Harvard Book Prize. And a big deal was made out of this in an awards ceremony. And I was very happy to win this prize, and when I went up and was awarded the book, I went back to my seat and was dismayed to find that the book I was given was a book about Harvard.

Zierler:

[laugh]

Jaffe:

I had hoped it would be some great work of philosophy, science, or fiction, but instead it was a collection of writings about Harvard.

Zierler:

So the matter of self-regard was just too much for you.

Jaffe:

I couldn't stand it. I love the egalitarian nature of MIT, and I loved the open nature at Stanford. And I thought the self-congratulatory style of Harvard was distasteful. And so I did not want to be a part of it at that point in my life. I was more concerned about issues of egalitarianism and social justice when I was a graduate student than I had been before.

Zierler:

This is clearly a very formative moment for you that obviously stayed with you for a very long time.

Jaffe:

[laugh] It was. Yes, I guess it was.

Zierler:

[laugh]

Jaffe:

So I visited—I got offers from the Institute and from MIT, and from Berkeley.

Zierler:

Did you have any interactions with the Institute as an undergraduate, or that was a totally separate world?

Jaffe:

Totally separate world.

Zierler:

Was that an exciting prospect to you? I mean, it’s the Institute. I'm just curious if there was something that might have been really attractive about that.

Jaffe:

Yeah, it was. And Murph Goldberger was very—twisted my arm a lot. He seemed to want to see me go there. Actually, I think I might have applied to Rockefeller as well, because I remember Abraham Pais trying to convince me to go to Rockefeller as well. But I didn't want to go back to Princeton. I visited the Institute. I spent a weekend there, or a day during the week and then a weekend day there, and I just thought that returning to Princeton at that stage in my life was not a good decision.

Zierler:

And the Institute felt like Princeton? It didn't feel like it was its own thing that would have been a new experience for you?

Jaffe:

Oh, it would have been a new experience in terms of physics, but it would have been the same experience culturally.

Zierler:

And what was your impression of the Institute in terms of what life was like there, what kind of opportunities you might have had?

Jaffe:

I thought the physics was excellent. It was dominated by Adler and Dashen at the time—Steve Adler and Roger Dashen—who were doing really excellent work in the kind of physics I was interested in, although in retrospect they were near at the end of their creative periods. But it was a pristine, isolated campus in a small town, and I didn't want to be in a small town in an isolated campus again.

Zierler:

You're answering in terms of personal and cultural decisions. What about the extent to which you were thinking about where to next take your research? Were you looking specifically to continue on with your work—with your dissertation? Or were you open to new projects that could be sort of out of the box in a new setting?

Jaffe:

I think I was still surfing on the light cone, as my advisor used to say.

Zierler:

[laugh]

Jaffe:

I had met Ken Johnson at an Irvine conference in the Fall of 1967, and had had wonderful conversations with Johnson about what was going on in particle physics. I met Francis Low at the same conference. They were both faculty members at MIT. Viki Weisskopf was at MIT. Steve Weinberg was at MIT. Gabriele Veneziano and Sergio Fubini as well. MIT was really the highest point on the planet.

Zierler:

Did MIT—was your sense—did it still have an upstart feel to it at that point, or was it more really established? Because I know earlier, it certainly had that feel.

Jaffe:

You mean to me, or you've heard that from other people?

Zierler:

I've heard that from other people, but not specifically in the timeframe when you arrived there.

Jaffe:

No, it seemed like the center of the universe in many ways. It turns out that many of the people there who were attractive to me were only temporary. But I think the thing that made MIT really special to me at that time was the atmosphere created by Viki Weisskopf. He was a little bit like Sid Drell—or I should say Sid Drell was a little bit like Viki, and I hadn’t realized that Viki was the source of this. But Sid was a very open and man-of-the-earth style. He’d talk to anybody about anything. And Viki was a real humanist of the old school and a very gentle and generous person. And his style permeated MIT.

Zierler:

So when you say the atmosphere that he created, what does that mean? What kind of atmosphere did he create?

Jaffe:

Anti-hierarchical, open to conversations, respected young people with their ideas. And fundamentally phenomenological, which appealed to me very much. It went back to my days of rock collecting. I felt that physics should be driven by observation and that the best theoretical ideas would emerge by confronting and trying to explain experiments. And that was very much in tune with what I learned to be Viki’s point of view about the world.

Zierler:

Now the postdoc opportunity at MIT, was there an understanding that this is something that would turn into a tenure-track opportunity? Or that was a separate consideration?

Jaffe:

There was nothing at all implied.

Zierler:

What did you work on when you got there?

Jaffe:

I first started working there on the generalized use of field theory to derive what are called sum rules. I had done some work on sum rules while a graduate student at SLAC. The summer after I came to MIT I gave lectures at the Santa Cruz Summer School with John Ellis on deep inelastic phenomena, and we derived what became well known as the Ellis-Jaffe sum rule on polarized inelastic electron scattering. And the idea that you could derive rigorous results about the properties of hadronic states relating them directly to precise experiments was just fantastic. And I was very excited about exploring the possibilities of that kind of theoretical tool for relating deep theory to experiment. I was also beginning to become—and this was emerging during my later years at SLAC—I was becoming fascinated by this seemingly contradictory phenomenon that quarks inside hadrons were apparently permanently confined, but at the scales at which they could be probed, weakly interacting. So the possibility that you could have weakly interacting particles permanently confined seemed like a contradiction. And it was one of the outstanding theoretical questions at the time. Could you formulate such a picture?

Zierler:

Why did it seem like a contradiction?

Jaffe:

Well, if particles interact weakly, you can pull them apart from one another. [laugh] You know, electrons interact relatively weakly, and it’s easy to knock an electron out of an atom. Quarks seem to interact relatively weakly. The phenomenon of Bjorken scaling was a statement that their interactions were negligible. And yet when you hit a proton with an electron, nothing—no quarks came out. And this was the confinement puzzle. This was emerging as a fundamental puzzle in the theory of strong interactions by 1972. There was no theory—QCD did not exist as a theory, but the components of QCD were around and being manipulated in ’71 and ’72, largely by this crew of young people at SLAC playing with currents and other operators built out of quark fields, and understanding their interactions with one another. But the puzzle of why the quarks didn't appear in nature was really not understood. And so I was very much interested in exploring that possibility as a postdoc.

Zierler:

How much were you publishing at this time? How much were you attending conferences, interacting with your peers?

Jaffe:

All the time. I was collaborating with a couple of different groups in England, and Llewellyn Smith by that point was back at CERN. Ellis may have been at Caltech. Broadhurst was in England. Jack Gunion was another postdoc at MIT. I was going to conferences three, four, five times a year, which was a lot for those days.

Zierler:

Were you teaching also, at that time, as a postdoc?

Jaffe:

No.

Zierler:

Were you working with graduate students?

Jaffe:

Yes, by the time I was later in my postdoc.

Zierler:

What were the developments leading to your offer to become assistant professor?

Jaffe:

Well, that was shortly after we developed the bag theory of hadrons. Starting in the Fall of 1973, my second year as a postdoc, or the summer—actually, it was the summer of 1973 working with Ken Johnson and two other postdocs, Charles Thorn and—or actually, Charles was the assistant professor, and Alan Chodos and then Viki Weisskopf—on developing a consistent quasi-field theoretic, Lorentz covariant description of confined quarks. So we actually developed a theoretical framework in which quarks were weakly interacting within hadrons but impossible to remove from hadrons, and showed that that could be done in the context of a field theory without contradicting anything. So it became really the first relativistic, predictive, field-theoretic description of confined quarks and gluons.

Zierler:

And the idea was that this project was significant that—time to offer you a tenure-track line?

Jaffe:

I wasn’t part of that discussion. [laugh]

Zierler:

Who made the offer to you? Was it Weisskopf?

Jaffe:

No, it was probably Herman Feshbach, who was at that point the head of the Center for Theoretical Physics. But at that point in the winter of ’73, ’74, I had assistant professor offers from Harvard, Columbia, and a staff position offer at SLAC, and an offer at MIT, to stay at MIT.

Zierler:

So of course Harvard was off the table, I'm sure, right off the bat, but what about Columbia, or going back to SLAC?

Jaffe:

Well, going back to SLAC was really attractive, I have to say.

Zierler:

Also, later on, maybe Northern California culturally had calmed down a little bit from when you were there?

Jaffe:

Oh, it had started to calm down, yeah. Harvard was off the table because their assistant professorships were not really tenure track. Harvard had two faculties, and so you had to pass through a gauntlet. Although I had very good collaborations and friendships with Harvard assistant professors—Tom Appelquist and Alvaro De Rujula, and Helen Quinn, actually—I felt that they were very talented, and they were on their way not to getting tenure at Harvard. So I wasn’t attracted to Harvard. Regarding Columbia—T.D. Lee was very convincing, but Columbia had a bad reputation for young faculty. I did not have an offer from Princeton. I don’t even remember whether I applied to Princeton. I might have gone to Princeton at that point. But the idea of teaching was very attractive to me, and has always been very attractive to me, and I didn't want to go to SLAC because of that.

Zierler:

Yeah, we haven't really talked about that yet. Did you do any teaching as a graduate student at Stanford?

Jaffe:

I actually did teaching as an undergraduate student. I gave some lectures in a series, a kind of ad hoc series, on field theory and second quantization, to other undergraduates through the auspices of the group I was working in. And then as a graduate student, I had an NSF, but the NSF [laugh] was not very financially supportive in those days. I think I had $300 a month to live on. And I took a job as a TA for courses at Stanford, so I TA’d at Stanford.

Zierler:

And you liked teaching?

Jaffe:

I did, yeah. And I was good at it. And I got a lot of positive feedback on it, and I really liked the way in which I was able to organize my understanding of physics through teaching.

Zierler:

And in thinking about the dim prospects as an assistant professor at Harvard and Columbia, your sense was that MIT, that was not the case. It was a good place to start out a tenure line.

Jaffe:

I was given to understand that, and I was also really excited about what was going on at MIT at the time. We were having a great time with the bag model. It was the salad days of quark model physics.

Zierler:

So in the end, it was a pretty easy decision for you, it sounds like.

Jaffe:

It was. It was a pretty easy decision. I liked Boston as well.

Zierler:

When you were named assistant professor, did you take on graduate students right away, or that came later on?

Jaffe:

I co-advised graduate students at that point. So I worked very closely with graduate students who nominally were working for other people.

Zierler:

And you started teaching undergraduate courses and graduate courses?

Jaffe:

I started teaching both undergraduate and graduate courses.

Zierler:

What were some of your favorite courses to teach?

Jaffe:

So electrodynamics, the senior-year course, the Jackson-level course in electrodynamics. The graduate sequence in quantum mechanics, I taught relatively early. So there was a two-term graduate sequence in quantum mechanics that I taught and helped to develop the syllabus for.

Zierler:

Did you do any like Physics 101 courses?

Jaffe:

Not really. Mostly, the freshman courses were taught by the experimentalists at MIT, and the more advanced undergraduate major courses and graduate courses were taught by the theorists.

Zierler:

And was your sense that, at least for the undergraduates, that they were taking physics classes because they were going on to engineering degrees, or were they mostly looking to pursue a career in physics?

Jaffe:

You can’t imagine how wonderful it is to teach physics at MIT. The physics majors at MIT are there because they want to be there. Their love of physics is infectious.

Zierler:

That’s where my question is coming from, because not only have I heard that about MIT, but I've also heard that that’s very unique to MIT. That there’s really not that many undergraduate departments where you really see this critical mass of undergraduates who are there because they really want to be there and want to pursue physics intellectually and professionally.

Jaffe:

Right. And I've likened it to teaching art history in Rome.

Zierler:

[laugh] Wow.

Jaffe:

I mean, how could you—? My daughter did a term in Rome doing art history, and I met the professors who lived in Rome and taught art history in Rome—what a life—and you just can’t imagine a more exciting place to teach physics than MIT.

Zierler:

And then in 1975, you were a Sloan Fellow.

Jaffe:

In passing, yes.

Zierler:

Oh, that was just a minor thing?

Jaffe:

Everybody was a Sloan Fellow in those days.

Zierler:

What does that mean?

Jaffe:

Well, if you were a successful young theorist, at some point in your first two to four years, you got a Sloan fellowship, which gave you $20,000 to spend.

Zierler:

So that was because the Sloan Foundation really just wanted to generally support theoretical physics?

Jaffe:

I don’t know. All my colleagues were Sloan Fellows [laugh] at some point.

Zierler:

So it was just basically handed to you? There wasn’t really much to it?

Jaffe:

Yes.

Zierler:

Huh. Interesting. So then in 1976, you did a full year at SLAC?

Jaffe:

I was at SLAC from early January through September, so I did nine months at SLAC.

Zierler:

What was your goal? What did you want to accomplish while you were at SLAC, for that time?

Jaffe:

Well, I had some ideas that it was possible to use this bag model that we had invented to explore areas of hadron physics that were at that point open questions. That there were questions about the substructure of matter that people didn't understand much about at all. I felt that it was possible to use this tool as a way of probing those areas that had not been looked at. And I was partly interested in what were called exotics and multi-quark states, and states made of gluons. And the possibility that there were important problems in particle physics of hadrons—in the physics of strong interactions—that could be resolved by looking at agglomerations of more than three quarks within a well-defined model like our MIT bag model, and I was very interested in doing that during that research leave.

Zierler:

Now when you were initially involved in bag theory, were you thinking ahead that this was really work that needed to be pursued within the context of a place like SLAC, or it didn't have to be?

Jaffe:

MIT was a very congenial place to do that physics.

Zierler:

So what did SLAC allow you to do vis a vis bag theory that you might not have been able to do at MIT or elsewhere?

Jaffe:

I just think it was a place to get away to, where I felt comfortable. I don’t think it was a particularly ideal place to do the physics I was interested in. There was interest at SLAC in these ideas, so I had a natural environment to talk with people about the mechanisms of confinement. By 1976, things had moved on from our original excitement in 1973 and 1974, and there were two different veins of gold to explore. One was the application of these theoretical ideas to solving phenomenological problems, and the other was the attempt to derive this picture from more fundamental ideas in QCD. And the thing I was most interested in was confronting phenomena with the ideas of quark dynamics. And that was something that was appreciated at SLAC.

Zierler:

And when you first considered the possibility of going to CERN, how did that come about? Did they invite you? Did they express interest?

Jaffe:

That was in 1979, 1980? [pause] I think my friends at CERN encouraged me to come there? But I don’t think it was a formal process. The senior management in the theory group at CERN was very distant and formal. I think Léon Van Hove was head of the theory group, and one did not talk to Léon without an appointment. But by that point, De Rujula was visiting CERN? And Llewellyn Smith was at CERN. And maybe Altarelli was at CERN? So there were people of my generation and slightly older who I wanted to be doing physics with. I guess Llewellyn Smith was at Oxford. So it was Altarelli, De Rujula, Ellis, who I was interested in being around at CERN.

Zierler:

What were your impressions of CERN?

Jaffe:

[pause] Not as interesting a place to be as I would have hoped. The main interest in CERN was in the dynamics of heavy quarks, of the then-discovered charm quark, which I thought was less interesting than the physics of light quarks, because the heavy quark dynamics was a simpler model, and light quark dynamics offered more challenging theoretical puzzles. I thought the seminar atmosphere at CERN was exciting. People were coming through CERN. I met Russians at CERN, and that was enjoyable. But I haven't preserved a very strong memory of the atmosphere at CERN. I was more interested in being at Oxford the first half of that sabbatical.

Zierler:

Oh!

Jaffe:

So I spent the first half of that sabbatical year of ’79, ’80 at Oxford. What I really wanted to do was talk to Dick Dalitz—Richard Dalitz—and also collaborate with Llewellyn Smith, which was a good time for me.

Zierler:

What was Dalitz working on, at that point?

Jaffe:

Dalitz was working on the understanding of baryon resonances in terms of quarks. And I was trying to convince Dalitz of the virtues of looking at quarks from my perspective. I was trying to convince him that there were some important problems in hadron dynamics that could be solved in terms of multi-quark states. So by that time, I had written a couple of papers on the role of states made of more than three quarks on the phenomenology of the light mesons. This may all sound somewhat out of vogue at the moment, because this is a long time ago, but in those days and I think still nowadays, some of the most problematic particles in strong interactions are the lightest mesons with scalar quantum numbers.

Zierler:

Now when you say problematic, what do you mean, problematic? In terms of understanding them?

Jaffe:

Yeah, they didn't fit into the picture of mesons made of quarks and antiquarks. How strong is your background in particle physics?

Zierler:

Not—I mean, I'm a historian of science, so I pick up what I can, but—I'm following you so far.

Jaffe:

So the idea was that mesons were made of quarks and antiquarks, and baryons were made of three quarks. That was the fundamental paradigm. And some mesons are well described in terms of their spectrum and interactions as made of quark and antiquark. But there are a set of very important mesons low in the spectrum that dominate the forces between hadrons, which are called scalar mesons. They have no spin. That’s what “scalar” means --- they have vacuum quantum numbers. But they are responsible for the primary attractive nuclear force that holds nuclei together. And in the quark model, mesons with those quantum numbers should be much heavier, quite long-lived, and relatively weakly interacting. And that’s completely in contradiction to their other properties. They're very light, they're very short-lived, and they're very strongly interacting. And I had shown that in the context of the quark bag model, that there was a set of states made of two quarks and two antiquarks that should have the right properties and spectrum to describe those mesons. And so I was advocating this position, these ideas, in the hadron physics community. And I was only partially successful in convincing people that this idea should be taken seriously. The papers have been—these are interesting papers. They have thousands of citations now. Their citation history has been constantly growing. And the reason is that the idea has slowly been accepted by the particle physics community.

Zierler:

So when you say partially successful, what were you able to convince your colleagues of, and what were you not able to convince your colleagues of?

Jaffe:

Well, the spectrum of these mesons is extraordinary. If you make mesons out of light quarks and antiquarks, they should come in groups of nine. And most of the mesons that had been discovered and well-studied did come in these groups of nine, with four relatively light, four medium heavy, and one very heavy. So the spectrum was four, four, and one. And the spectrum of the light mesons was upside down, one very light, four medium heavy, and four very heavy. And this upside down spectrum was the natural prediction of this four-quark picture. And that’s the most striking prediction. Various people who worked in the field immediately embraced that and said, “Oh, that’s a great idea.” And other people said, “These particles are too strongly interacting for us to understand them in this picture.” And there was even a question of whether these states existed at all, because they were so short-lived that there were very broad effects in the scattering experiments as opposed to being sharp peaks that you could associate directly with particles. So the question of whether these states existed was controversial, and if they existed, what they were made of was controversial. And it has taken—those papers were written in 1976, when I was at SLAC, and what is this now, 43 years later, we now know the states exist, and it’s generally believed that they're made of four quarks.

Zierler:

And what was the discovery that we now know that these states exist?

Jaffe:

No simple discovery. Long, careful analysis of scattering data, extrapolations into the complex plane, the work of many people over many decades.

Zierler:

But it’s no longer controversial at this point?

Jaffe:

It’s still a bit controversial.

Zierler:

When you transitioned into tenure and then full professorship, how does that change in terms of your role as a graduate advisor? Because you said when you started out, initially you had co-advised with others. I assume at some point, you're taking on full responsibility of individual graduate students and probably you're taking on more graduate students?

Jaffe:

One of my great regrets as a professor is that I've never had that many graduate students, for reasons that are perhaps complex. But as a result, I've had relatively few graduate students. And during that time, I had a couple of very intense relationships with graduate students that were very productive. But not that many graduate students.

Zierler:

Were there people that wanted to work with you, and for whatever reason, you weren’t able or did not want to take them on? Or were the people that did want to work with you just sort of self-selected and were a relatively narrow group of people? Or maybe a combination of the two?

Jaffe:

I would say it was a combination of both. I think that a lot of the graduate students at MIT were attracted to working with Roman Jackiw, who was a very successful field theorist and very successful graduate student advisor. And I was also—maybe I was a little too intolerant of the foibles of graduate students.

Zierler:

You said that you did have a few graduate student relationships that were very productive. Can you describe them?

Jaffe:

So in the period between 1979 and 1982, I had a graduate student named Mark Soldate who I worked very closely with on a massive project exploring what are called higher twist effects in deep inelastic scattering. There were three groups involved in this work at the same time. There was a group at CERN—Roberto Petronzio, Keith Ellis and their collaborators—and there was a group in the Soviet Union, Arkady Vainshteyn and Edward Shuryak. And there was Soldate and myself working at MIT. And the attempt was to use the same methods that had been used to understand quark dynamics in the dominant terms in inelastic electron scattering to classify and make predictions for the first corrections, the effects that die away at large momentum transfer but still could be isolated. And Mark was a terrific collaborator and a brilliant student, and we had a great time working together. We worked together intensively as a collaboration and developed the whole theory in a self-contained and predictive way, so it was a very productive time.

Zierler:

Other productive graduate student relationships that really come to mind?

Jaffe:

With a Polish graduate student in the mid ‘80s who was very interested in the physics of states made of gluons—Zbigniew Ryzak was his name. And we did a lot of good work together. Another student named Chaba Korpa in roughly the same period. Ryzak went on to work successfully in the financial world, and Korpa is a tenured professor in Hungary.

Zierler:

I'm interested—when you said it’s a regret that you didn't take on more graduate students, it’s interesting because, you know, some eminent professors, they have a crazy amount of graduate students, like a dozen or year or something like that. And many just don’t really have many, ever. And so it seems to me a lot of it is a personal decision. So when you say a regret, why is that? Is there a larger debt that you owe the field that you feel like you didn’t pay? Or you had opportunities to positively influence more graduate students that you didn’t have? Why not just simply say it’s a personal decision, and that’s just the way it went?

Jaffe:

I don’t think it was so much a decision as a personality characteristic, that I tended to work on problems that I didn't understand what they were until I actually solved them. So the people who have had the most success with graduate students have very large, structured programs, and you solve the problem for situation A, then you move on to solve the same problem for situation B. And I never worked that way. I tended to work on problems that I didn’t even understand what the question was until I already understood the answer.

Zierler:

But certainly you don’t have regrets about the way that you did physics, and yet, if that is inextricably linked to the feasibility of having graduate students, perhaps that’s just the way it worked out.

Jaffe:

Yeah. Maybe that’s true. But I think that my way of doing physics is a valuable way, that I feel that the intersection between phenomenology and theory is a place where a lot of insight is gained, and what I regret is that I didn’t have as much of an opportunity to promulgate that way of doing physics.

Zierler:

Can you talk a little bit about your work in an advisory capacity for some of the national laboratories?

Jaffe:

Sure. My primary role in advising national laboratories was at Brookhaven. I played a significant role at Brookhaven in several ways. I was on their program advisory committee. Brookhaven had a low-energy proton accelerator, what is now regarded as a low-energy proton accelerator, that was capable of doing very high resolution, very careful experiments involving the scattering of hadrons. And there, a lot of their program involved issues that I was deeply concerned about during the ‘70s and ‘80s. As time went on, Brookhaven moved toward higher energies and towards a collider program on what’s now called the relativistic heavy ion collider. And the relativistic heavy ion collider was built as a nuclear physics machine to study the collisions between things like gold nuclei. But a small group at Brookhaven realized that it was possible to polarize spin—align the spins of protons in the same machine and study the quark spin substructure of protons and neutrons in that environment. They tried to put together a proposal to run this machine as a polarized ion collider. And this was a field that I had—we haven't talked about this, but I did a lot of work on the spin substructure of protons and neutrons, and really was one of the leaders of that field. And I became really excited about this possibility at Brookhaven, and they enlisted my help as an advocate for this machine. And so I was very involved in building up what’s now called the RHIC spin program, which was a strong collaboration with a Japanese group, and the Japanese institute called Riken set up its first overseas laboratory at Brookhaven. And I was involved in setting up that laboratory. So I acted as advisor to this aspect of the spin program.

Zierler:

Who were some of the major collaborators there, with you, from the Japanese side?

Jaffe:

It was almost entirely experimentalists. So I was working with experimentalists on that. There were a few theorists like Werner Vogelsang and Larry Trueman. And T.D. Lee was a leader in that, as well, from Columbia. But the experimentalists I worked with were Naohito Saito who is now the director of the J-PARC laboratory in Japan, Shoji Nagamiya, Gerry Bunce. And let’s see. There were several others who were players in the Brookhaven establishment. Oh, and Nick Samios, who was then the director of Brookhaven. And because of my role in this or because I was a good advisor, I was asked to serve on one after another of the major advisory committees at Brookhaven, who were helping to plan the direction of development of machinery and programs at the laboratory.

Zierler:

Did you get involved in policy-oriented issues with regard to DoE, or you were more on the actual research?

Jaffe:

I moved into a more advisory position that had a broader scope. There was a group called Science and Technology Steering Committee which reported to Battelle, the management company that ran BNL for the DoE. The DoE paradigm is that laboratories are run by contracts with external companies, and Brookhaven was run by Battelle. So Battelle collaborated with University of New York at Stony Brook on the fundamental management of Brookhaven, and the Science and Technology Steering Committee was the senior committee that advised the director of Brookhaven and the management groups, on the scientific policy and institutional issues at Brookhaven. And I was on that committee for a decade and chaired the committee for several years. And that was dealing with everything from issues of what kind of accelerator would be built in the future at Brookhaven, to what happened when safety rules were violated at Brookhaven.

Zierler:

Did you enjoy the advisory work?

Jaffe:

I did enjoy it. [pause] I constantly struggled in my career between the public arena of physics and the private pleasure of doing research and teaching. And I vacillated back and forth a lot.

Zierler:

When you were named the director of the Center for Theoretical Physics at MIT, I wonder if that afforded you an opportunity to sort of develop that interplay.

Jaffe:

Well, actually, it developed before that, when I was named the Chair of the Faculty at MIT. So I served two years, three years in all, as Chair of the Faculty dealing with institutional issues at MIT.

Zierler:

Oh, so you saw your chairmanship that you had that there was availability to sort of interface more broadly with the public, as chair?

Jaffe:

Well, the Chair of the Faculty interfaces with the institutional administration. The faculty at MIT does not have a faculty senate. It has one person who represents the faculty, like the union shop leader, and interfaces with the senior administration and the Corporation i.e. the board of trustees at MIT.

Zierler:

I've heard the word “corporate” be applied to the MIT hierarchy before. I think that's interesting. How did you see that? How corporate was it?

Jaffe:

Not terribly corporate. The trustees are called the Corporation, but I think that's just a nomenclature. No, I thought MIT’s administration at the time was relatively open and creative.

Zierler:

Did you enjoy your time as chair?

Jaffe:

I did, yeah. I worked on very interesting issues.

Zierler:

Beyond the physics department, or mostly in—?

Jaffe:

This was not chair of the department. This was Chair of the whole MIT faculty.

Zierler:

I see, I see. So what kind of issues did you work on?

Jaffe:

These were not physics issues; these were issues of how to structure MIT to react to the end of faculty retirement. So faculty, the limit on defined retirement age was changed in the 1990s, and it was essential to reorganize MIT’s benefit structure, so I became involved in MIT’s benefit structure analysis. The medical structure at MIT was unusual, and I was involved in restructuring the medical system. The grading system was revised during that period. The academic calendar—I wrote the academic calendar at that time.

Zierler:

Oh, wow.

Jaffe:

And there was a program undertaken by the president on reengineering the academic administration, which was very controversial, and where the faculty were up in arms, and I had to interface between the faculty and the administration.

Zierler:

Why was the faculty so upset?

Jaffe:

Because they felt it was an upside-down —it was a top-driven reformation that rewarded the wrong people, instead of the people that were actually doing the work. Faculty were very dedicated to the administrators they worked with, and they felt that they were getting moved around in a way that suited the central administration but not the individual faculty. Faculty politics are very complicated, sometimes. Sometimes the issues seem very minute from the outside, but they're quite a challenge to deal with.

Zierler:

So to get back to ’98, when you're named director for the Center of Theoretical Physics, what was attractive about that opportunity to you?

Jaffe:

Well, there was the possibility of an upcoming renovation of our space. And so I was extremely interested in rebuilding the physical Center for Theoretical Physics in a way that would help to keep and increase the openness and generosity of the environment for young people.

Zierler:

How far back did the Center go? What was its history?

Jaffe:

It was started in the mid-1960s by Feshbach, Kerman, and Weisskopf.

Zierler:

And how much had it grown over those years? It started off relatively small, or it was big from the beginning?

Jaffe:

Started off on two floors of one building and was relatively static in its size until the ‘90s when it grew, and then it has recently grown even more.

Zierler:

What were some of your goals and agenda taking on this role?

Jaffe:

Well, faculty renewal was a major issue. At that point, there were half a dozen faculty who were reaching retirement age and had not retired, and I worked with the department head to try to find creative ways to help them into retirement and hire new young people in their place, and bring in new blood into the particle physics and the nuclear physics efforts there.

Zierler:

Does the Center have its own faculty or it’s all joint appointments with physics?

Jaffe:

It’s a section within the physics department. So it’s not joint; they're all professors of physics, and the Center is one of the laboratories, institutes, and centers within MIT.

Zierler:

So by having a separate organization within the physics department, what can be accomplished that can’t simply be accomplished just within physics generally, the department generally?

Jaffe:

Well, the administrative structure in a department like ours is very complicated. There’s a matrix structure. The departmental structure is a vertical structure at MIT. Then there’s a horizontal structure which are laboratories, centers, and institutes. And so the Laboratory for Nuclear Science is a part of the horizontal structure which is a home for people doing research in particle and nuclear physics. So the Center for Theoretical Physics has administrative responsibility within the physics department. It’s a division. We don’t make appointments. We propose appointments. We undertake searches for new faculty. And we construct promotion cases—with the Institute—within the Laboratory for Nuclear Science. We are the vehicle by which the Department of Energy supported particle and nuclear theory at MIT. So I had to report to the Department of Energy on nuclear and particle theory activities in the Department of Physics. So the CTP director has responsibilities to the funding agency, the Laboratory for Nuclear Science, and to the physics department. But the opportunities for creative change have to do with appointments, securing better funding for postdocs, and especially in this case with a major renovation that could shape the whole way that people did physics within the Center. So much of my energy was spent on this renovation project.

Zierler:

Can you talk about the circumstances leading up to you being named the Morningstar Professor? How did that come about?

Jaffe:

Chaired professorships are rewards for distinguished service both in terms of creative physics and in terms of service within the department. And the weighting between physics creativity and achievements within the university is usually complex. So I think my appointment was in recognition of my contributions to particle physics. I think in the 1990s, the efflorescence of spin physics was receiving a lot of attention. I had been very involved in that. I had led much of it. And my influence on the teaching program had been very influential.

Zierler:

Were you the first Morningstar Professor?

Jaffe:

No, I was the second Morningstar Professor. Jane and Otto Morningstar had been MIT graduates. I think Otto was the graduate; Jane was his wife. They had made a lot of money in constructing micropore filters using particle beam methods, actually. Micropore passed particles through sheets of Lexan and then etched the particle tracks, making tiny pores that allowed them to make very fancy filters. Otto made a fortune and gave a lot of it back to MIT, some of it after his death, by Jane, who was—I knew Jane; I didn't know Otto. And they endowed a professorship in the early 1990s which was held by a condensed matter physicist named Toyo Tanaka, who died unusually young in the late 1990s. And then the position was given to me.

Zierler:

I'm always curious, when there are chaired professors who have a relationship with the benefactor, is there any discussion about—I don’t know if expectation is the right word, but do you have any sense that there’s anything that they specifically want to have accomplished by endowing this chair? Or it’s more simply a matter of just giving back and allowing it to be used to recognize excellence?

Jaffe:

In some cases, there may be an expectation of performance, but in the case of Jane Morningstar, she was just delighted to hear the latest advances in particle physics. Going out to lunch with her was a chance to give back, through my description and enthusiasm, some kind of reward for her making this possible.

Zierler:

So now we're getting into the recent past. I wonder if you could talk a little bit about your current and recent past research. What are the kinds of things that you've been working on in the past decade?

Jaffe:

So I made a decision in—let me telescope this a little bit. In the late 1980s and 1990s, I became—my research was dominated by the understanding of the spin substructure of the proton. And then I felt that I had done what I could do in that subject, and I moved on to a program that had fascinated me for a long time, which was the study of the dynamics of the quantum vacuum, so the forces between particles and between macroscopic objects that are generated by the fluctuations of quantum fields in the vacuum. And that dominated my research interests between I would say about 2000 and 2012. And then, in about 2006, I started becoming interested in—I had always been interested in energy issues, but I think I veered back to my interest in social and science-in-the-public-interest issues, and became committed to trying to establish an educational program at MIT on the physics of energy. In order to create the time to work on these educational goals, I descoped my research. Parenthetically, I feel that theoretical physicists do their best work when they're young. I think that many theoretical physicists have aged badly.

Zierler:

[laugh]

Jaffe:

That the tendency is to continue to beat on the drums of your youth. I watched physicists, when I was a young researcher—listening to gray old physicists give introductory and summary talks at conferences where they were more tolerated than appreciated. And I felt that the time had come for me to put aside my research and to work on something that was useful.

Zierler:

So let me just interject there. If theoretical physics is a young person’s game, is that because the intellectual rigor just requires an energy and youth that’s not available later on in life? Or is there something—I mean, because the other way of looking at it is, you get wiser as you get older. So why doesn't it work in that regard?

Jaffe:

I don’t think it does work in that. I feel I may be controversial in this, but I think that wisdom doesn't count for a lot in theoretical physics. It’s not like history and literature, where you accumulate a broader and broader world view. It’s not a question of energy; I have plenty of energy. I just wrote—just finished writing this massive book.

Zierler:

[laugh] Took a lot of energy to write that book. [laugh] Yeah.

Jaffe:

It’s a big book. It’s hopefully the authoritative textbook on the physics of energy. But I feel that theoretical physicists make progress primarily by seeing something in a different way. That people who have looked at a problem—when they look at a problem, they don’t know what coordinate system to look at it in. They don’t know what tools to bring in it. And if they're not too influenced by authority, they take their own point of view. Maybe they look at it at 45 degrees, whereas everybody has already looked at it at right angles. And when they see something different, they make a lot of progress by exploiting their different point of view. But that’s a one-off. Once you've seen something differently, then you become wedded to your point of view, and you can’t look at the same problem with a different point of view. So I think that once you've confronted a problem in theoretical physics, you've usually made your major contribution right up front. Now, some people reorient themselves entirely to a new problem, and in that case may bring a new point of view to that new problem. I think to some extent I did that with the vacuum fluctuations question. I hadn’t worked on it before, I joined in a collaboration with some very powerful people, and we saw it from a different point of view. But that requires a big investment in terms of reeducating yourself into an arena so that you can even think about a new problem. So I think most theoretical physicists do their best work when they're young, because they see problems fresh for the first time.

Zierler:

That gets me to a broader question I was going to save for a little later on, but I think it’s a good place to ask now. Aside from your ideas about aging and different perspectives, how much of it was simply a motivation to have a more practical impact beyond theory?

Jaffe:

I think that’s an important part of it. As I mentioned, I've always felt that science is a [pause] tool for the public good, and I feel that scientists have an obligation, since we're supported so generously by society, to pay back with contributions to society. And throughout my career I've tried to do that in one way or another, sometimes episodically. Sometimes I got deeply involved in physics problems that captured my entire attention. But in my late fifties, when I undertook this project, I felt that I could use my skills as a teacher and as a writer to establish a curriculum in a field that didn't have a curriculum, and allow anybody who had the basic tools of a scientific education to learn the fundamental science between energy systems and uses.

Zierler:

Before you started thinking along those terms and you were more exclusively focused on theoretical endeavors, at that point, did you ever concern yourself about the quote-unquote practicality of your work? For example, some theoretical physicists don’t care about that, and some care deeply about it. And among those who care deeply about it, some have achieved success in the practical realm, and some have not. And so before you started thinking in those terms with your most recent projects, how would you have placed yourself within that range?

Jaffe:

Well, if you mean practical in terms of applied, I didn't. I never worked on applied physics.

Zierler:

No, but I'm saying even if you didn't self-consciously work in applied physics, you could have been involved in theoretical endeavors the directly led to practical applications of the research.

Jaffe:

Yeah. So I think for a person whose fundamental interest is in particle substructure and in the properties of the vacuum, things like that, the idea that your work would lead to something practical is kind of distant, to say the least. I didn't see that. I have very strong opinions about the importance of phenomenology in fundamental research, so in that sense, I feel that fundamental research not guided by the real world is questionable. And I have vigorous discussions with my colleagues about that. But I think physics is about the real world. Physics is a response of the human mind to try to order and understand the way the world works. In that sense, everything that I've done has been practical. But it hasn’t led directly to applications or even toward things that at a second level would lead to applications.

Zierler:

So your development in issues relating to energy, is that because your—in addition to your concerns about political and social issues, what value do you bring to this new work from your background in theoretical physics?

Jaffe:

The strength of the fundamental tools of an undergraduate and early graduate school physics education. The fact that we can talk about entropy and energy conservation, about the limits on dynamical systems in a way that is powerful and sophisticated. And if you've taught it for a long time, you can develop tools for communicating that broadly to a culture that needs to know it.

Zierler:

I don’t think we really specifically historicized when you developed these interests in energy issues. When did this start to happen for you?

Jaffe:

I think my frustration at the second Bush admin…Bush Jr.’s first term—his misuse of elementary ideas in science in response to energy crisis issues just got me to the boiling point. So when George Bush Jr. announced the hydrogen economy—that hydrogen is the fuel of the future—and when that announcement was made by a Secretary of Energy named Bodman, who had been an MIT PhD in chemical engineering and but appeared not to understand the first laws of thermodynamics, I just found that the opportunity at MIT to establish a course that would be open to any undergraduate with the freshman requirements, to learn enough to not make the misguided statements that were being made by Bush administration appointees.

Zierler:

And it was problematic because it’s not feasible to have a hydrogen economy?

Jaffe:

Hydrogen isn’t a fuel! Hydrogen is an energy storage system. A fuel is something that you dig out of the ground or that comes to you from the sun and that provides you with energy ob initio. You make hydrogen, but you use a fuel to make hydrogen, and then you use it. So it’s an elementary misunderstanding. And I hoped that an elementary education in physics would help to forestall that.

Zierler:

I see. So you were looking to, as a corrective to this, train a new generation of physicists, or in your own way, be part of that larger trend, so that these kinds of things wouldn't happen in the future?

Jaffe:

Well, I think I was a little more positive than that. I was trying to—not only physicists. This course is not a physics major course. It’s a course for anybody at MIT, including—we've had political scientists, economists, engineers of course, architects. And the idea is to provide them with the basic tools of science in order to more effectively work in the direction of climate change and energy resources.

Zierler:

So you've been at this now 15, 20 years. That’s enough of a distance where you've seen at least a generation, if not two, of students enter into the workforce. What kind of feedback are you getting on what has been accomplished so far?

Jaffe:

Well, it’s an uphill struggle. The world is not moving in a good direction, because we don’t have really good leadership. But the people that came out of this program initially have moved on to advisory positions, research positions, and investment positions, many of which have contributed on the good side of energy and climate issues.

Zierler:

So what do you see—again, this idea that you're coming at this from your political and social justice concerns—is this because you basically see climate change as a—well, I mean, a political problem and a social justice problem?

Jaffe:

Yeah. Originally when we started this project, I and Wati Taylor—Washington Taylor, who’s my co-collaborator in this—we thought we were helping to educate people who would eventually help to improve the future trajectory of the world in technical means. We thought we were helping to educate researchers. But as time has gone on, we have become more and more convinced that the fundamental problems are political, social, economic, and regulatory.

Zierler:

Yeah, yeah.

Jaffe:

Nevertheless, in order to have an intelligent discussion at the economic level, at the political level, or in terms of regulations, it’s necessary to understand the scientific foundation of these issues.

Zierler:

Yeah. So in a perfect world where you can sort of not have to deal with the political and the economic and the regulatory and all of those other issues, and it was just physics unleashed, so to speak—physics unencumbered—what is it that you and what you represent could accomplish in terms of dealing with climate change?

Jaffe:

That’s a kind of funny question. That’s a non-existent world.

Zierler:

Right. But I'm saying without all of those other things, and in a perfect world where what you're trying to accomplish is just unencumbered by those other factors, what would that look like? A world in which there’s no more fossil fuels? I guess that's where I'm going with the question.

Jaffe:

So the pieces are largely in place to have a world in which energy resources are provided through renewable systems. Solar energy is abundant. It’s now cheap enough through the development of low-cost photovoltaic modules. Wind energy is abundant and in many ways equally inexpensive. And if not thwarted by political obstructions and economic barriers, they would be the foundations for an almost carbon-free economy at the present time.

Zierler:

Are there certain industries or modes of transportation for which renewable energy sources are not yet viable? Like airplanes, for example?

Jaffe:

I'm working now with a group at MIT on a study through the MIT Energy Initiative on the future of storage. And one of the outcomes of our study is that storage is expensive, and it’s easier to overbuild resources like wind and solar energy, because they're inexpensive, rather than rely on just-right building and storing energy. So building those resources to cope with periods of low solar energy and low wind, and then using the otherwise curtailed power in times of high solar energy to produce low-carbon fuels. Electrolyzing hydrogen with otherwise excess power and producing hydrogen and hydrocarbon fuels for airplanes, and other uses for which electrical energy can’t be used directly. So I think I'm trying to answer your question. If you can displace carbon-based fuels in the electrical grid, and power automobiles electrically, you can power homes electrically, you can power lots of industry electrically using solar and wind energy. It’s very difficult to use solar—electrical energy directly to run airplanes and a few other specific applications. And you need to have high density transportable safe fuels like kerosene to do that. And the possibility of producing hydrogen using otherwise curtailed electrical power is one of the ideas that’s coming forward.

Zierler:

Where do you see civilian nuclear energy in the mix?

Jaffe:

Transitory. I mean, if it weren’t for the fact that the public perception of radiation is so anomalously toxic, nuclear energy would be a relatively low-cost, low-carbon transitional fuel that would lead us to a better path to a low-carbon energy economy.

Zierler:

And do you see advances in technology and infrastructure that would essentially make disasters like Fukushima irrelevant for the future? Or are those kinds of problems, would they always be there?

Jaffe:

I think there are a lots of advances in nuclear technology that are already available that would make for safe power plants. Although Fukushima was a disaster, it’s nowhere near the disaster that we're comparing it with in terms of climate change.

Zierler:

Right, right.

Jaffe:

I mean, how many people died as a result of Fukushima, and how many people will die through human migration in response to climate change?

Zierler:

I want to go back now to like the late 1960s and early 1970s. Do you see this as these are things that have always stayed with you? Or were you sort of less focused, at least on a daily basis in the interim years, between your time as a graduate student and when you got involved in energy issues? Did you always sort of—intellectually, I'm sure you always cared about that, but did you really pick this up in terms of things that you actually devoted your time to, ten, 15, 20 years ago? Or have you always been active in these regards?

Jaffe:

I haven't always been active. I was very active as a graduate student, but in a way that feeds almost directly into this project in energy. These workshops on political and social issues that I started at Stanford were precisely the use of the academy to try to develop ideas that had direct social impact. That idea that you could use the tools of education, especially within the context of a high-quality research university, to develop policy recommendations and to train or to educate and inspire young people to work at the interface of science and public policy has been a constant ideal of mine.

Zierler:

So of course, with climate change, the science is very sobering, as is the political and economic inertia. But I wonder how optimistic you are, as an educator, as somebody who is sort of on the front lines with younger generations, in terms of their intellectual rigor, in terms of their feelings of social justice, in terms of their recognition of the existential reality in their own lifetimes. I wonder how optimistic you are in that regard.

Jaffe:

Most of the students I encounter are fantastic. They are dedicated, passionate, inspired, and committed. They are unfortunately not a good sample of the population averaged over the world.

Zierler:

But I guess my question is, do you feel like they have what it takes to sort of address these issues?

Jaffe:

You have to understand, I'm not an optimist about the future. In fact if we were having this conversation over a beer, I think you'd find my pessimism would triumph.

Zierler:

[laugh]

Jaffe:

I think as long as we don’t control the population and as long as we don’t have a better way of developing leadership at the political level, I think that the human experiment may well be doomed. But that doesn't mean—I mean, I have to find something to do with my time, and it seems to me that within the context in which I'm living, this work on energy is a better thing to be doing than not.

Zierler:

I want to come back to that for my last question, but now, I want to ask a few broader questions about your career, just sort of writ large. Do you see any one particular contribution as head and shoulders—I mean, you've been involved in so many things of major import. Is there anything that sticks out to you, either as a personal accomplishment, or as a professional contribution, more than others, in terms of your overall contributions to the field?

Jaffe:

Well, I would say not, actually. I think my major contributions can fall under a broader umbrella as the elucidation of the quark substructure of matter. Some of those parts were assembled before I entered this field, but some of the most powerful pieces of that puzzle were put in place as a product of my work and through my collaborators. And I think people will be discussing how protons are made of quarks for a long time in the future and they'll be trying to answer questions that I first asked, and they'll be using tools that I first developed. So that’s maybe the broadest way in which I could say that.

Zierler:

You frequently reference controversies in your field over the course of your career. I wonder, do you see yourself in a particular intellectual tradition, where your ideas connect with those of a previous generation, and with the generation ahead of you, in terms of if there are any constants in terms of the way you see the world or the way that you've developed your ideas?

Jaffe:

I think that I'm an intellectual child of people like Viki Weisskopf, who felt that theoretical physics lives in service to the world, to the structure—that the task of theoretical physics is to unravel the structure of the world as we observe it. That the questions that are posed to us by nature are the ones that are interesting to try to resolve. I think that puts me squarely in the phenomenological side of theoretical physics. I'm proud to be there. I think that that’s where the greatest progress has been made over the years. I feel that people who do abstract theoretical physics often wander into sterile, mathematical worlds where they contribute very little to the understanding of the universe. And I would defend the work of the younger generation that’s trying to build a better understanding of the substructure of matter and the role of matter in the universe as being a primary objective for theoretical physics.

Zierler:

If you can reflect from the beginning of your career to now, what was mysterious either to you or to your field and you as a representative, that you feel is truly understood now? Something before that was not understood and really is understood now?

Jaffe:

That’s a real softball of a question. I think hadrons—I think the strong interactions are the great revolution of my time. I think that it’s really a classic example of a Kuhnian revolution in physics. That in the 1950s, nobody knew what hadrons were. Nobody knew what the strong interactions were. People started unearthing ideas that made no sense, like quarks, and that seemed to work for reasons that they couldn't understand. They kept calculating using tools that were blunt and poorly understood, and they kept getting results that seemed to enticingly agree with experiment. And then at some point, the gestalt just shifted, in the 1970s, mostly because 1970 and ’72, suddenly the possibility that the strong interactions that determine most of the structure of the universe could be understood in terms of quarks and gluons became a reality and reshaped our understanding of matter. You couldn't conceive of how poorly understood the structure of matter was when I entered the field. In 1964, when I was a freshman at Princeton, if somebody said that six years later, we were going to understand what protons and neutrons and their friends were all made of, you would have received no reception at all. And so I think that is really the major revolution the I've been involved with.

Zierler:

These things work in concert with each other, but what do you see as the primary mover of these discoveries? Is it advances in technology? Is it insight? Is it just the slog of doing hard work with collaborators over the years? What really accounts for these massive developments over the course of your career?

Jaffe:

Well, I think it’s the union of great experiments founded on improvements in technology, of course, but the incredible organization and toil of great experiments combined with a theory community that’s broad, intercommunicative, and tolerant. I don’t believe in the great man theory of theoretical physics. I think that if you look at quantum chromodynamics and the emergence of quantum chromodynamics, it involved so many people in so many ways, so many theorists in so many ways, building this house of cards, one card at a time, until they had really created a wonderful structure. The people that are singled out—for example, my colleague Frank Wilczek and David Gross and Hugh David Politzer, who won the Nobel Prize for proving asymptotic freedom, they were putting the last candle on a cake that had been baked and frosted and constructed by a whole community of theoretical physicists. And they were inspired by some absolutely seminal experiments done by experimentalists who took great risks in proceeding against the better judgment of the larger community. So deep inelastic scattering experiments were not the favorite experiments of their time. Kendall, Friedman, and Taylor did an experiment that was largely dismissed in advance, and it was a big risk to their career, and they achieved great results as a result.

Zierler:

So to flip the question on its head—maybe this is also a softball question; maybe not—what’s mysterious today that you're surprised at? That you would have figured by now would have been figured out but hasn’t?

Jaffe:

Dark matter. I think the principal accessible phenomenological question on the plate for fundamental physics at the present time is, what is dark matter, and where does it come from, and what can we learn about our universe from it. You've heard of dark matter.

Zierler:

I have. And dark energy is the other—

Jaffe:

Yeah, I did not say dark energy. [laugh] I said dark matter.

Zierler:

What is your feelings on dark energy?

Jaffe:

Well, dark energy is related to this work I did on the quantum vacuum. Dark energy is a property of the vacuum. The vacuum is almost unprobeable. And so I think that the possibility of understanding the origin of dark energy is very distant for us, so I'm not optimistic about that. But I do feel that dark matter is both a very practical problem, because it helps to shape the structure of our universe, and it’s definitely there.

Zierler:

Do you see a—like the Socratic way of the more that you understand, the more that you understand you don’t understand—is there any end point to that loop that you see? Is there a level of understanding that sort of puts it all together? Or you don’t think like that?

Jaffe:

Well, I'm not sure if you mean like a grand unified theory?

Zierler:

Yes.

Jaffe:

I think at some point, gravity and quantum mechanics will have to be reconciled with one another. I think that our understanding of the universe is incomplete without that reconciliation. But I don’t see a master equation or fundamental unification of everything to be an essential ingredient. I think we're exploring, and our exploration of the universe is still like a blind person tapping their cane in the darkness. I mean, we explore what we can access experimentally and through phenomena, and various parts of the universe will never be accessible to us.

Zierler:

And is that because of fundamental limits to what humans can understand, or because simply the universe might not lend itself to understanding? In other words, is there a fundamental reality to the way that the universe works, regardless of our ability to understand it or not?

Jaffe:

You know, that’s above my pay grade. [laugh]

Zierler:

[laugh]

Jaffe:

I'm not even sure—I mean, if you're asking me whether that’s an ontology underneath all of this empiricism that I've been talking about, I don’t know. I think that the human perception of the universe was developed over billions of years of evolution. Here are you and I having a conversation as if you exist and I exist, but you're just a bunch of pixels on the screen, as am I. Our organization of reality is tempered by the world that we live in, by the perceptions that we register, not by some underlying “reality”. That’s our tremendous advantage, but that’s also our tremendous limitation. Quantum mechanics is a wonderful laboratory for understanding the limitations of ontological descriptions of nature. In quantum mechanics, there is no fundamental reality. There’s just a set of experiments and results that can be mathematically reconciled with one another. One of the mysteries to me that you didn't mention is why mathematics has anything to do with it. I mean, I think that that’s one of the great puzzles that we don’t even know how to address—whether mathematics is some fundamental structure of the universe, or whether it just happens to be the logical system that our evolution has imbued us with.

Zierler:

I think for my last question—I know you've already shown your cards as a pessimist in terms of population and social and political and economic issues. But I wonder, as a physicist, as a scientist, what excites you about discoveries that are around the corner, either in your lifetime, or in the next however many years that you want to put that. What are things that you think are achievable for that next generation, that you're actually really at the front and center in terms of training that next generation?

Jaffe:

Well, you have to remember, I'm 73 years old and about to retire, so as far as training the next generation, that’s a wish list for me. But I think that there are specific things, like we're going to understand a lot more about the universe through black hole astronomy. That’s kind of low-hanging fruit. There’s a wonderful future in the next 20, 25 years as we begin to understand how our universe is populated by these incredible objects. But I think the real future in fundamental science lies in emergent systems. That the role of the fundamental forces in structuring the—in understanding the way the universe is put together is reaching a level of completeness that we wouldn't have anticipated when I first entered the field. I think we understand enough about the strong, the weak, the electromagnetic, and the gravitational interactions, so that we can claim to have a fundamental understanding of phenomena at the micro level. What we don’t understand is what happens when you put together Avogadro’s number of particles, when you put together 1023 particles. Our minds have a really hard time conceiving of the complexity of structure that can emerge from the coherent and self-organizing abilities—abilities is a tough word because it implies some kind of teleology—but the self-organization that occurs in complex systems. And I'm not only talking about life and living systems, but I'm also talking about relatively simple things like the behavior of materials. Even quantum chromodynamics is a wonderful example of this. That the fundamental description of nature that we have in QCD is in terms of quarks and gluons, but all the phenomena in QCD are emergent. There are no quarks and gluons observed in the universe. What we observe are hadrons and their interactions. So the entire structure of nature is emerging at that level. Now, that emergence is not as complex as what occurs in systems with Avogadro’s number of particles. But the behavior of fluids, the behavior of elastic media, the behavior of conductive media, meta materials—all of these things are lying in the future. I think that’s a very exciting future.

Zierler:

Well, Professor Jaffe, it has been a delight talking with you today. I really want to thank you for the time you spent with me.

Jaffe:

Well, I hope it was useful. I'm not sure, but thank you.

Zierler:

Absolutely, absolutely.

Jaffe:

It was a pleasure talking to you as well.

Zierler:

Thank you.

Jaffe:

Thanks for your time.