How did you learn that you received the award?
I had just come back from Europe, from Holland. And I was sitting at my kitchen table paying bills. On my computer screen appeared a message from Edward Witten, a famous physicist and chairman of the search committee. The message said, “When can I phone you, and what is your number? So I answered, “Now,” and provided my phone number. And then I continued paying my bills. But no phone call came.
After 20 minutes, I looked again at my computer screen and saw a second message from Edward. “I phoned your number but got Johnny Johnson in Massachusetts.” Ugh! I saw that I had mistyped the area code. So I wrote back, “This is the correct number – perhaps jetlag?” Immediately afterwards, the call came through.
I was afraid he would ask me a difficult question about supergravity, he’s very smart. I was nervous that I might not know the answer. I picked up the phone and he said, “This is Edward Witten. I’m happy to inform you that you won the Special Breakthrough Prize for Fundamental Physics 2020.”
That was a total surprise for me, because for many years, we expected that we were in the running for the prize. But each time, other people won. They were all absolutely excellent physicists, so we never had any qualms, but after so many years, I stopped thinking about receiving the prize. So when Edward said that we won, I was absolutely speechless. So I said, “Well, I’m speechless. I had completely given up hope.” And then he said, “No need to say more. Please do not inform anybody else.” And that was it. It was the shortest and most rewarding phone call of my life.
In regard to the discovery of supergravity, are we still waiting for “the big reveal, the proof?“
The proof is there; the theory exists, mathematically everything is clear. The prize is for the theoretical work we did. But it is not clear if this is a theory of Nature. Only when supersymmetric particles are discovered will our theory become physical reality. I’ve always ended my articles with “Let us hope that Nature is aware of our efforts.”
Do you feel that today, we have the technology and resources to discover the supersymmetric particles?
So far at Fermilab near Chicago and CERN near Geneva, no supersymmetric particles have been found. There’s talk of a new accelerator in China, we’ll wait and see.
How did you come to work on the concept of supergravity with Freedman and Ferrara?
Friedman was teaching here, and Ferrara was at CERN. On a trip to Paris, Freedman met Ferrara and had a discussion with him about the concept of supergravity. When Freedman came back, he brought me into the loop. We worked here together, actually right in this office, and we had phone and letter contact with Ferrara throughout the process.
Walk us through the experience. Was there an “a-ha” moment?
Yes. We reached a point where a calculation was very, very complicated. It was so complicated, after many months, we thought we could not do it. But I had learned to work with computers from my adviser, Nobel Laureate Veltman, so I decided to put the problem on the CDC computer, nearby in Brookhaven. We got results back and forth on the phone. We tried to make the program as inexpensively as we could, because we were afraid of the expense. So the bill was about $30 to $40, which nowadays is considered absolutely nothing for such a program.
Late one night, I was sitting here in an office with the computer, and by this time, it was our last go; everything had been checked, and there was no way to adjust or modify things anymore. There were 2000 coefficients that had to be zero. They were integers. So precisely zero or one or two, but not 0.1 or 0.2 and so on. So, the computer program didn’t have to use high precision. If any one of these coefficients was nonzero, then the theory would not exist, and we would have wasted a lot of time.
The first batch came in, then the second and third batch, and so on. We already knew that the coefficients in these first batches vanished because we had done previous runs — we had been able to make them zero. The issue was whether all other coefficients were also zero. The batches continued to come in from Brookhaven – 1600, 1700, still zero – 1800. 1900, finally 2000 and all coefficients were zero! At that moment, I knew that the theory existed.
I was very tired. In the middle of the night, I phoned Friedman who in a hotel at a conference in Chicago, and I said “Well, Dan, it all works.” And he said, “That’s wonderful.” And then yawned and went back to sleep.
People had asked if I was excited, elated, but honestly, I was very tired after all of those months of work. So I went back home to sleep. Only in the days after did I realize that this was a major discovery.
Was it celebrated here at the University?
In the beginning, there was no prize, we just had to write an article for the scientific community. We published the findings in The Physical Review. We later added an addendum to the article stating that the computer calculation showed that the theory existed.
On a personal level, I was made Leading Professor, and later, Distinguished Professor. I did get some offers from other institutions, but I decided to stay here. And that was, I think, a wise decision.
So in short, the discovery was rather anticlimactic?
Well, you have an aim all the time. And the aim keeps you on your feet. You’re coming closer and closer, but when the aim is achieved, you feel spent.
You’ve been at Stony Brook since 1975, and you mentioned that staying was a wise decision. How so?
The main reason I like to be here is the advanced graduate courses I teach; the students are absolutely fascinated with these courses, and that motivates one a lot. It’s very rewarding to have such an audience that wants to learn from you.
And you’re also affiliated with the C.N. Yang Institute for Theoretical Physics?
Yes. Frank Yang recruited me in 1975; he was my director. He was always very, very supportive and that was another reason why it was so nice to be here.
Tell us about that.
I was in Boston at the time, and was hesitant to come because people told me that New York was a very dangerous place. The first time I came, I was walking near the old Physics building when I saw a young man running away from an older man, who dove on the young man and pinned him down. When I saw that, I was very afraid. It turned out that the younger man was a student impersonating another student, therefore committing fraud; the other person was a professor who was trying to get the student.
Regardless, I went back to Boston, but Yang phoned me that I should come back. I went back, and gave a talk that initially went very well, everyone was listening. But afterwards, suddenly everybody left me and hurried to another corner in the room. Someone had come in from Brookhaven with a piece of paper showing a huge, unexpected peak in measurements. That later turned out to be the charmed quark. I decided to accept the offer to become assistant professor.
So what do you plan on doing with your newfound fortune?
It’s a surprising amount of money. I haven’t thought about it, because I didn’t even think we would get the prize. Fortunately, that is not a problem I have to solve immediately.