On the morning of October 19, 2022, I woke up to a terrible news: Valery Rubakov has passed away.
Valery was my PhD thesis advisor. Every time I introduce myself to Russian physicists (or physicists from the former Soviet Union), after saying “I studied in Moscow,” I would add “I was a student of Valery Rubakov.” No words that I could use to describe myself would elevate my status in front of Russian physicists more immediately than that simple sentence “I was a student of Valery Rubakov.”
It is clear why it is so. Valery was a giant in particle physics; he has done so many groundbreaking works: the Rubakov-Callan effect (for the lay audience: how a hypothetical particle called the “magnetic monopole” can turn matter into energy), electroweak baryogenesis (an explanation of why the Universe contains only matter but no antimatter), an early suggestion of the braneworld scenario (that we are living in a world with more than 3 spatial dimensions, and that the extra dimensions do not have to be small) and many other things. Valery was also famous in Russia as a science popularizer and a staunch defender of scientific institutions against political interference.
I already heard legends about Valery as an undergrad at Moscow University, so deciding to do PhD under him was the easiest decision. I entered the PhD program at the Institute for Nuclear Research (INR) in September 1991. Valery was then the Vice Director of the Institute, responsible for the Institute’s scientific work. Our Theory Division (“Teorotdel”) is housed in a three-story building. Valery’s office was on the second floor, while I was in a shared office on the third floor. Normally Valery would work his day job as a Vice Director until some time in the afternoon, and come up to our office around 4pm or so to discuss physics with us over tea and cookies (pryaniki). I learned a lot from these conversations, but more importantly, they made doing physics an enjoyable, human endeavor.
I was a junior member in a small group at INR trying to understand whether very high-energy collisions lead to violation of baryon number (i.e., create more matter than antimatter). At the end, the problem remains unsolved, but there are many hints that the effect remains too small to be observed even at very high energy. At the beginning there were only three people in our group: Valery, Peter Tinyakov, and myself. Later a few younger people joined the group (Dima Semikoz, Maxim Libanov and Sergey Troitsky). The group felt like a tight-knit family: we were all members of the Rubakov school.
The possibility to have his own school was perhaps what kept Valery in Russia. He could have moved to the West in the 1990s, but he once told me that the mobility of scientists in the West, generally a good thing, also makes the existence of “schools” (in the Soviet sense, like in “Landau school” or “Bogoliubov school”) impossible. Valery enjoyed working with and cultivating younger scientists, and the structure of a Soviet physics school fits his style the best.
The INR was an oasis of sanity in the crazy world of 1990s Russia. The euphoria (if there was any) of August 1991 quickly subsided, replaced by a general tiredness and despair of a society undergoing a chaotic transition to Wild West capitalism. But Rubakov managed to get us enough money to not to have to worry too much about having enough to eat, so we could just concentrate on physics. Many friends of my age had to leave physics to go to business. Without Rubakov, I am not sure where I would end up now.
There was at least one occasion when the craziness of the external world seeped into our oasis. Once a visitor came to see Valery. Normally Valery received his guests in his office, but for some reason, he received that visitor in our third-floor shared office. The visitor came in and, seeing me sitting at my desk, asked Valery in a somewhat surprised voice “Your institute employs these?” From his voice and gesture it was obvious he thought that a Vietnamese should not be in a Russian institute. I tried to appear undisturbed. Valery was irritated, he said “Shon (that’s how my name sounds in Russian) is a PhD student (aspirant) in our theoretical division; he is a member of our collective.” Then the visitor started talking to Valery in a low voice. He talked about some issues in science politics, I wasn’t sure what these were. But at some point the visitor said “We should do something, otherwise the Jews are going to ruin us.” Valery immediately pointed to the door and told the visitor to get out.
For me, Valery set my standard of what constitutes a solution and what it means to understand. Whenever I think that I have solved a problem, I would step back and ask myself: do I understand the issue at the level that I would feel comfortable explaining it to Rubakov? When I write something, or make a presentation, sometimes I would ask myself: does my explanation meet Rubakov’s standard of clarity?
The last time I met Valery was in March 2019, at the informal conference RU-10000002 on the occasion of Rubakov’s 64th birthday (1000000=64 in binary) at the INR. I remember at the cocktail party before the conference dinner, somehow the conversation drifted to politics. I said “When I was in Moscow (i.e., until 1995), the things that are happening between Russia and Ukraine would not be imaginable.” Valery said: “This is also unfathomable to me. To be honest I don’t think I understand why the Ukrainians want to be in Europe so much. The European Union has tons of problems. But Ukraine is an independent country and the Ukrainians have every right to do whatever they want.”
After the war broke out, Valery was one of the first scientists to sign an open letter opposing the war. That was a strong letter which explicitly named Russia as the party solely responsible for starting the war. I was worried about Valery’s safety, so I sent an email to him. I wasn’t sure if the letter would be read by a third person, so I only tried to tell him what I thought of the current events using an expression from his open letter: “Shag v nikuda” (a step to nowhere). Rubakov wrote back to me saying “I agree with your assessment” and said that many people are frustrated, so moral support from people outside the country is valuable.
I was waiting for the war to end to visit Valery again. Alas, that is now impossible. But Valery will live forever in my memory.
(photo: Valery Rubakov and his wife Elvira at an anti-war protest in Moscow, March 2014)