WHEN I WAS SETTLED at RIAS again after my time at CERN and my father’s funeral, Robert Oppenheimer invited me to give a talk at the Palmer Laboratory in Princeton. Oppenheimer, whom I had met previously at the Einstein Fest in Bern, was one of the gods of U. S. physics in the mid-twentieth century. He had been the director of the Manhattan Project that produced the first atomic bomb. He was interested in the preprint that Brian Bransden and I had sent out from CERN on our prediction of a resonance in the P-wave pion-pion scattering amplitude, later known as the rho-meson. This was still months before the actual publication of the paper in Physical Review Letters.
At this time, I was beginning to feel apprehensive about the future of RIAS, and I thought it was time to put out feelers for an academic position. Welcome Bender, our director, who was not a scientist, officially worked at the Martin aircraft company even though he was director of our institute, where only fundamental physics and mathematics research was being carried out. During this time of the cold war, the army, navy and air force, which supported our fundamental research, always believed that we would produce the science that would lead to a useful new lethal weapon to threaten the Soviet Union. Perhaps my research on pion-pion scattering suggested to the military that I might be able to produce a “pion bomb.” On the other hand, I had heard rumours that the aircraft company had lost enthusiasm for supporting a fundamental-research institute, and it was possible that they might close it down in the near future, which made me feel even worse about having turned down the job offer from CERN.
Thus, the invitation from Oppenheimer to speak at Princeton sounded like a good first step towards applying for a position at Princeton or elsewhere, and perhaps getting a letter of recommendation from Oppenheimer.
My talk at Princeton was actually organized by the celebrated quantum field theorist Arthur Wightman, who was a professor at the Palmer Laboratory, which was the Physics Department at Princeton University. He invited me to stay at his house in Princeton, and we had a delightful evening together, as he and his wife were charming hosts. Wightman was a tall, handsome man in his thirties, and his wife was a tall, striking woman who also had a faculty appointment at Princeton. During dinner, the conversation flew along on erudite topics, such as the fine points of Greek mythology and many arcane details about the tsetse fly, which causes so many deaths in Africa through sleeping sickness.
I gave my lecture on a Thursday morning before lunch. The title of the talk was “New Results on Pion-Pion Scattering and the Inverse Scattering Amplitude Method.” Already a little nervous before the lecture, when I walked into the seminar room, I was taken aback at the number of famous physicists who sat staring at me as I approached the podium. Oppenheimer, of course, was there, as well as Murph Goldberger, Samuel Treiman and Eugene Wigner.
Wightman introduced me as a young physicist who appeared to have solved some fundamental problems in pion-pion scattering. After a nervous beginning, I got warmed up, and gave a detailed presentation on the discovery of the P-wave resonance that Brian and I had made during the previous year at CERN. However, soon, members of the audience, particularly Sam Treiman, a well-known professor in particle physics, started bombarding me with intense questions. I tried to keep calm and answer his questions as well as possible. When I finished my talk, the formal question period began, and I was assailed by yet more questions. It was all reminiscent of my experience with Pauli, and then his student Källén, and I was glad I had learned to remain relatively unrattled when under attack by older physicists.
Wightman came up to me at the end of the talk to tell me that we were going to lunch prior to a faculty meeting in the Physics Department. The lunch was held in a faculty room, and I sat opposite Eugene Wigner, with Arthur Wightman on one side of me and Valentine Bargmann, the renowned Princeton mathematician, on the other. Murph Goldberger presided at the head of the table, and presumably was going to chair the faculty meeting after lunch too. Eugene Wigner, Paul Dirac’s famous brother-in-law, was a Nobel Prize winner for the important work he had done in nuclear physics. He was well known for his polite, even obsequious demeanour and for asking simple questions that could turn out to be devastating. He leaned across the table and asked innocently, “Moffat, do you mind if I ask you a simple question? Can you explain to me what crossing symmetry is?”
Wightman chuckled, and Goldberger also seemed amused. I explained as well as I could what I understood about crossing symmetry, a fundamental mathematical property of scattering theory. Wigner peered at me intently for a few moments, said nothing further and continued eating his lunch. I sat and wondered whether my future would depend upon how I had answered Wigner’s question.
The next day, before returning to Baltimore, I planned to visit the Institute for Advanced Study, which was some distance away from the Princeton campus. I wanted to let Professor Oppenheimer know that I was interested in an academic position, to sound out whether anything might be available at Princeton or the institute, and to ask whether he would be willing to write a letter of recommendation for me. I walked through the hallowed halls of the institute, found a door bearing a plaque that said “J. R.Oppenheimer,” knocked and walked in. A stern-looking, middle-aged lady sat at a desk. Her greying hair was combed back tightly into a bun and she wore thick-framed glasses. “Can I help you?” she asked.
“My name is John Moffat. I’m from a research institute in Baltimore. Professor Oppenheimer invited me to Princeton to give a talk, which I gave yesterday.”
She said curtly, “Yes, I heard about this.”
“Is it possible for me to see Professor Oppenheimer before I return home?” She rose from her desk, walked over to another door and knocked on it. There was a loud “Come in!” from inside.
Several minutes passed while I waited for the secretary to return from Oppenheimer’s inner sanctum. Finally, she came out, closed the door behind her and said brusquely, “I’m sorry. Professor Oppenheimer cannot see you.” I got up, feeling baffled, and didn’t know what to say. I thanked her lamely and left.
As I wandered around the institute grounds, I pondered why Oppenheimer wouldn’t see me. Was my talk that bad yesterday? I didn’t think so. Did I fail some secret test at lunch, which he had heard about? What had I done wrong? So much for asking him for a letter of recommendation in my applications for university positions. Such was academia. You could never be quite sure about your position. The behaviour of academicians, and physicists in particular, tended to encourage a certain degree of paranoia in one’s personality.
Some months later, I ran into a colleague at a physics conference who had heard about my talk at Princeton, and who was doing research at the time in Berkeley. He told me that he had heard via the grapevine in the Physics Department there that one of the prominent professors in the S-matrix group had heard about Oppen-heimer inviting me to give a talk at Princeton, and, being upset with Bransden and me for beating him to the prediction of the P-wave resonance, or rho-meson, had sent a telegram—the e-mail of the 1960s—to Oppenheimer. In it, he said that he had read the preprint sent out from CERN by Bransden and myself, and noticed right away that the figure describing the resonance bump in the P-wave scattering amplitude had a kink in it. This kink could only be caused by a serious discontinuity in the calculations we had performed, the telegram continued. Consequently, the whole calculation must be incorrect, and Oppenheimer should disregard everything I said.
I was astounded by this report, suddenly recalling my difficulties with the Gestetner instrument, and demanded to know from my colleague whether he really believed this was true. He said yes, he was pretty certain it was correct. I already knew that physicists could be brutal in their treatment of competitors, but this was truly beyond belief. Of course, it explained why Oppenheimer had refused to see me the day after my talk, and it certainly killed any hopes I had had for obtaining a position at Princeton.
Despite this dispiriting experience, I began travelling to Princeton every other week to attend seminars at the Institute for Advanced Study. It was a wonderful opportunity to hear well-known and talented physicists such as Abraham Pais, Julian Schwinger, Murray Gell-Mann and many prominent visitors talk about particle physics and quantum field theory. As director of the institute, Oppen-heimer presided over the lecture, and discussions continued over afternoon tea.
Oppenheimer was in the habit of dominating the seminars. I learned that he would spend an hour or two preparing for a guest speaker’s seminar, and then would usually sit in the front row, close to the speaker in the institute’s moderately sized seminar room. There were usually no more than fifteen to twenty physicists in attendance. Not long after the speaker had commenced, Oppen-heimer would almost invariably interrupt, and explain to us what the speaker was really trying to say.
John Geoffrey (J. G.) Taylor, who had been a student at Cambridge during my years there, was visiting the institute as a fellow, working on the dispersion relation methods in particle physics. He told me that on arriving at the institute, he and his wife, Pat, were invited to the Oppenheimers’ impressive house on the outskirts of Princeton. The evening had turned out to be embarrassing. At the outset, Oppenheimer’s wife had offered them drinks, and unfortunately, Pat dropped her glass of red wine on the floor on an expensive rug. Oppenheimer rushed out of the room, returning with a pail of water, which he threw dramatically on the rug in front of them. Later, in a conversation after dinner, Pat Taylor intimated that she had learned to play the piano as a child. The Oppenheimers insisted that she play their Steinway grand piano, and a nervous Pat Taylor was forced to play Chopin. Not having practised recently, she did not perform very well, much to the Taylors’ embarrassment.
Oppenheimer, in his usual critical way, made a testy comment about her playing.
John Taylor and I were in a prankster mood one day, and agreed it was time for “Oppie” to learn a lesson. Besides, I had never gotten over Oppenheimer’s treatment of me after my talk at Princeton. At Oppenheimer’s seminar that day, an invited speaker was talking about dispersion relations, which both Taylor and I were working on. Sure enough, after no doubt preparing himself in his office to do battle at the lecture, Oppenheimer sat close to the speaker and rudely interrupted him. Taylor and I were stationed at opposite sides of the room, watching each other. On a signal from me, Taylor interrupted Oppenheimer while he was in the process of haranguing the speaker, and asked him a technical question that was not easy to answer. Oppie looked momentarily fazed, but then ignored Taylor and returned to dressing down the speaker. I then interrupted and asked Oppie another highly technical question, following up on Taylor’s question. Oppie looked at me quizzically, with an irritated frown, and tried to answer my question. “Well, Professor Oppen-heimer, this is not the correct answer,” I said matter-of-factly. From the other side of the room, Taylor butted in and agreed that what Oppie was saying was absolutely wrong.
At this point, Oppenheimer appeared to realize that we were ganging up on him. Suddenly he stood up, white in the face, strode across the room, opened the seminar door and slammed it shut as he exited.
Taylor and I suffered no repercussions following this seminar, but it was obvious that our little lesson had been completely lost on Oppie. At the next seminar, given by his former student Robert Serber, then a professor at New York University, Oppenheimer behaved in his usual egregious fashion, interrupting Serber relentlessly. At one point, he stopped Serber in midsentence, turned to the audience and said, “This is what Robert is trying to say,” and gave a five-minute summary of his talk, while Serber looked on helplessly.
Despite Oppenheimer’s critical and rude behaviour, the Princeton seminars were delightful. The talks were informative and I learned a great deal about theoretical particle physics.
Later, when I recalled the incident with Taylor and myself at the seminar, I felt some regret about our behaviour towards Oppen-heimer, who, despite his autocratic personality, was highly respected in the United States, as well as internationally. One understood from accounts by people on his Manhattan Project team that he had been a very successful administrator; indeed, his leadership was in large part responsible for the success of the project. When Oppenheimer later described the first test of the atomic bomb in the New Mexico desert, he made his famous statement about the grave responsibility of having produced this devastating weapon, quoting Hindu scripture:
A few people laughed, a few people cried, most people were silent.There floated through my mind a line from the Bhagavad-Gita in which Krishna is trying to persuade the Prince that he should do his duty: “I am become death: the destroyer of worlds.”
In later years, Oppenheimer opposed Edward Teller’s program to produce a hydrogen fusion bomb. During the McCarthy era, he was investigated for his involvement with the Communist Party while a young physicist at U. C. Berkeley. I think that the subsequent withdrawal of his security clearance by the FBI had embittered him, and might partially explain his behaviour at the institute seminars. It was clear that Oppenheimer was a complex person. I learned later that while he was a student at Cambridge, England, doing laboratory research, he had become insecure about his work, and had actually attempted to poison his supervisor, Patrick Black-ett. Remarkably, Cambridge University authorities treated him with leniency and allowed him to finish his research under close supervision.
Oppenheimer’s bizarre behaviour to me, personally, reasserted itself later when I encountered him at a physics conference. As I approached him and put out my hand, he said, smiling mischievously, “Ah, Bransden!” I said hesitantly, “No, Professor Oppen-heimer, I’m Moffat.” This exact exchange happened again not long afterwards, at another physics meeting. And again, Oppie smiled and seemed amused by his own trickery.
Our years in Baltimore coincided with the civil rights movement in the United States and with the cold war. Once, in October 1962, when I was driving from Baltimore to Princeton to attend a seminar and stay overnight, I caught the news on the car radio of the imminent launching of a nuclear warhead from Cuba. This was the climactic day of the Cuban missile crisis, and John F. Kennedy and Nikita Khrushchev were butting heads. The nuclear warheads were predicted to land on the east coast of America, pretty much where I was driving at that moment. I thought about Bridget and two-year-old Sandra back in Baltimore, and for several minutes debated with myself about turning around and going home. However, I continued to Princeton, and before my drive ended, President Kennedy had managed to prevent the crisis from escalating into war.
Just over a year later, I attended a conference in Dallas on new developments in astrophysics. It was only two days after the assassination of Kennedy. At the meeting’s opening ceremony, the organizers asked the audience for a three-minute silence in memory of President Kennedy. One day I went to visit Deal Plaza, and stood beneath the window of the book repository building from which Lee Harvey Oswald had shot Kennedy. The whole plaza and even the boulevard leading into it were carpeted with bouquets of flowers. On an American Airlines flight returning to Baltimore, I sat next to a large, stocky Texan in cowboy hat and boots. During a brief discussion with him, he told me that he was happy that someone had finally killed that “son of a bitch,” Kennedy.
The Dallas meeting had been an important one for the field of astrophysics. New observational results on quasi-stellar sources, later called “quasars,” were announced. This was a subject of much investigation at the time: How could such relatively small objects produce such large fluxes of energy? And how far away were they from us? I was fascinated by the new-found quasars, and soon made them a subject of investigation at RIAS.
But it was the aftermath of the Kennedy assassination, and the mixed feelings of grief and perverse satisfaction among the Texans I met, that remained with me after the Dallas conference. As a transplanted British citizen, I sometimes felt out of my depth in this often-violent country that also nurtured many of the most talented leading physicists in the world.