by Lev B. Okun, published 1990, in the Russian Journal Nature
November 1974, Moscow, House of Scientists, International
Seminar on Partons and Quarks. In between presentations I told Andrei
Dmitrievich about the work published by MB Voloshin, IYu Kobzarev and me. We
found that the vacuum can be unstable. For example, our world is capable of
spontaneously moving to a different, more stable state by the quantum-mechanical
tunneling-formation of a microscopic bubble, inside which is a new vacuum, and
outside, the old one. Once created the bubble would expand rapidly, its shell,
which has supra-nuclear density, approaching the speed of light, would destroy
our whole world. When I first thought that such a bubble could be created in
particle accelerators, where the particle beam collides with a target or another
beam, a cold chill ran down my spine. At this point Andrei D. interrupted me:
"Such theoretical studies should be prohibited." I replied that particle
accelerators work irrespective of such theoretical research and, furthermore, if
the universe ever had an unstable vacuum, it has long been replaced by a stable
one, because at an early stage all possible collisions took place. "But then no
one collided lead nuclei with lead nuclei" countered Sakharov. This conversation
took place at the White Hall of the House of Scientists, under a portrait of its
first director, MF Andreeva.
21 July 1976, Restaurant Aragvi in Tbilisi, Georgia, where a dinner party was held for the International Conference on High Energy Physics (XVIII in a series of so-called Rochester Conferences). There were lots of long tables, and at one of them I sat near Sakharov. The conversation meandered randomly, we started talking about quickness of wit, and then I suggested to Andrei Dmitrievich the problem of a bug on an ideal rubber band: You have a 1 km long rubber band with one end attached to the wall, and the other in your hand. The bug begins to crawl towards you on the rubber band, starting from the wall, at a rate of 1 cm/sec. As he crawls the first centimeter you extend the rubber band 1 km; when he crawls the second centimeter you extend the rubber band another 1 km, and so on, every second. The question is: Does the bug ever reach you, and if so, in how much time? Both before and after that evening I gave the problem to different people. One demanded about an hour to solve it, another demanded a day, the third remained firmly convinced that the bug does not reach you and the question of how much time is given to send you barking up the wrong tree. Sakharov asked for the conditions of the problem and a piece of paper. I gave him my invitation to the banquet, and immediately, without any comment, he wrote the solution on the back. All together it took about a minute.
May 23, 1978 at the International Workshop on Gauge Field Theories, held in the conference hall of the Institute of Control Sciences of the USSR Academy of Sciences on Profsoyuznaya Street in Moscow. Only two or three foreign participants attended. Most of those invited refused to come out of solidarity with (respect for) dissidents, and especially to protest YF Orlov's arrest in February. The boycott began in 1977, lasted many years, and became nearly universal after the invasion of our troops in Afghanistan and the expulsion of Sakharov in Gorky. About ten minutes before the meeting started Andrei Dmitrievich went to the blackboard, standing at the podium and carefully forming letters, he wrote: "We are grateful to all those who by their absence at the workshop expressed solidarity, and support our fight for freedom." I remember the meaning well, though not the exact words. The inscription remained about five minutes. Then a man, unknown to me, carefully whiped out the text. On the blackboard there remained shiny wet traces.