Frank Close is the author of the new book Half-Life: The Divided Life of Bruno Pontecorvo, Physicist or Spy. His many other books include The Infinity Puzzle and Neutrino. He is a professor of physics at the University of Oxford, and he lives in Abingdon, England.
Q: You write that you’ve been interested in Bruno Pontecorvo’s story for many years. What first intrigued you about him, and how long did it take you to research your book?
A: When I was a student in the 1970s I read a book by Laura Fermi, wife of Enrico, which she had written in 1953 and it ended with the news that Pontecorvo had disappeared from the face of the Earth.
That same week I saw a paper by Pontecorvo, written from a laboratory in the USSR. I wondered if anyone realised where he was. (Yes they did. Since 1955 when the Soviets suddenly produced him for propaganda reasons. However, Laura Fermi’s book wasn’t updated, unknown to me.)
I knew him to have been one of the major physicists of the 20th century, but largely unknown to people at large. I started to research his life for a biography in 2011.
His decision to flee to the USSR at the height of the Cold War affected his scientific career – in my judgment he missed a chance for a Nobel Prize as a result (the reasons and my argument are outlined in Half Life) and I became increasingly intrigued by the puzzle: Why did he make that fateful decision?
I live just five minutes walk from the house where he and his family left 65 years ago, and they are still remembered by people in the town. This, and other chance coincidences, metaphorically opened doors and from late in 2012 the espionage world of smoke and mirrors took an increasing role in my research.
Q: How would you characterize Pontecorvo’s contributions to nuclear physics, both before and after his move behind the Iron Curtain?
A: He was unusual in being outstanding in both experimental physics and in theoretical ideas. One leading physicist put him alongside Ernest Rutherford and Enrico Fermi in this regard.
He was a midwife at the birth of nuclear physics, during his time in Fermi’s laboratory as a student up to 1936, where he was a co-discoverer of the “slow neutron” method - key to the subsequent development of nuclear power, and of nuclear fission.
By 1950 he was one of the world’s leading experts on the practical details of the physics of nuclear reactors. The information that went to the Soviet Union in his brain was undoubtedly of great value to them at a time when they were developing nuclear technology for both peaceful and military uses.
He became an expert in the field of neutrinos – ghostly articles that are produced in nuclear reactors, in the sun and also (as Pontecorvo was first to point out) in supernova explosions.
His time in the USSR is most famously associated with the birth of neutrino astronomy, of which he was one of, if not the, prime founders. He realised that there is more than one variety of neutrino – a fact that is recorded for posterity on his tombstone.
Without doubt he would have shared in the Nobel Prize of 2002 (awarded to Davis and Koshiba for neutrino astronomy) had he been alive (he died in 1993.)
Q: You write, “It is my judgment that, in the summer of 1950, not even Bruno Pontecorvo anticipated that he was about to leave England forever.” Why is that?
A: All his behaviour, together with the way he went about the flight, suggest that it was a sudden decision. For example, you don’t leave your wife’s fur coat at home if you plan to spend the winters for rest of your life in the USSR! – nor leave precious family mementoes, photographs, wedding certificate etc.
He and his family were on a six-week camping summer holiday; all they had with them were camping gear. Again, inconsistent with a planned move to the USSR. Recall that a move to the USSR was perfectly legal and if he had wanted to go there, in an orderly fashion, he could have done so. There was no need to hide his intentions.
Furthermore, I discovered that just before he left for his vacation, the FBI made contact with the British security chief, with enquiries about Pontecorvo’s alleged communist connections. This information was intercepted in Washington, D.C., by double agent and traitor, Kim Philby.
That much I established as fact. It was Philby’s normal practice, and people close to the intelligence community are convinced that this would have been the case here too, for Philby to pass such information on to Moscow via his colleague Guy Burgess.
Philby in Washington to Burgess in London; Burgess to the Soviet embassy; from there to Moscow; by which time Pontecorvo is on vacation.
Only four weeks later, when he was in contact with his cousin, Emilio Sereni – communist member of the Italian parliament – was contact with him achieved. Within three more days, Pontecorvo and his family were on the plane to Moscow.
His son, 12 years old at the time and now a nuclear physicist himself (in Moscow!), also told me that everything seemed to him to have been sudden and unexpected. I think, with the Philby connection, we now have the reason why.
Q: There has been much debate about whether Pontecorvo actually was a spy. What are the arguments on either side, and what is your assessment?
A: To answer that question would require a book :) As Half-Life spells out: neither the FBI nor MI5 had any solid evidence, indeed, nothing more than gossip. If he was a spy he was one of the most successful – at least until he panicked after the Philby tip-off.
I draw an analogy with the theory of the planets pre and post Copernicus: you can fit with the earth at the centre if you make lots of epicycles, but put the sun at the centre and it all fits. Similar with Pontecorvo.
Suppose he passed no information: you can make his actions fit this, but you need several ad hoc excuses, analogous to epicycles, to make the fit; if however you assume he passed some information, it all falls into place. On balance: in a criminal court (beyond reasonable doubt) I would find him innocent; in a civil court (balance of probability) I would probably convict.
Q: What are you working on now?
A: A short book about my lifelong fascination with eclipses, provisionally called Dark Side of the Moon.
My next major project, on which I have already done a year of research, is about convicted atomic spy Klaus Fuchs, his relationship with his mentor – a father of the atomic bomb, Rudi Peierls - and his tormentors, the spooks of MI5 and the FBI. An obvious title, given the codename of the A-bomb test, is Trinity.
Q: Anything else we should know?
A: That Half-Life was the most exciting literary project that I have worked on. I never anticipated that I would meet in person the son of one convicted spy; the widow of another spy - who denied everything for years and got away scot-free; former heads of British intelligence; and also have correspondence with one former double agent, together with some influential people from the former Soviet Union who insisted on anonymity, and all this while researching what was intended to be a biography of a great physicist.
Anything else worthwhile that you should known is surely on file with MI5 or the FBI already ….. :)
--Interview with Deborah Kalb