Arkadii Migdal

Hoddeson:

Gordon Baym and I are having a conversation with Arkadii Migdal of the Soviet Union, who is on a visiting tour of the United States. We are in the Illini Union in Urbana. It is May 25, 1977 and very very hot. We would be very much interested in hearing some of your recollections from childhood, for example, what got you interested in pursuing a career in physics? We would like to know something about your parents, aspects that seem most important to you in relation to your career.

Migdal:

The best thing about my parents is that they didn’t interfere in my growing up and my studies and hobbies.

Baym:

In which year were you born?

Migdal:

In 1911.

Hoddeson:

Where?

Migdal:

In a small town close to Vilna.

Baym:

Did you go to school there?

Migdal:

No, I lived there up to four years and then my family left. It was the beginning of the war, the First World War. We went to another small town near, Minsk. I spent there my childhood up to 12 years, or something like that. Then I came to Leningrad at maybe 23 or 24, and lived there until 1940, and came to Moscow, a year before the Second World War.

Baym:

You mentioned the other night the book on physics of toys. Could you tell a little bit about that?

Migdal:

Yes. There is a very good book of physical games. The book was written by a Frenchman, I think; quite by chance I found this book some place. The author is Donat. The book contains the explanation of many physical toys which you should make yourself, and I tried to make many of them.

Baym:

You were how old then?

Migdal:

I started at eleven years old. It was my start in physics. But I think my first idea — I didn’t know that there is theoretical physics and experimental physics so I thought it was more experimental physics. I was interested also to make some inventions. For instance, I invented a thing which is now very widespread. I don’t know if it was known at that date or not. I invented a regulator for current, in case of a short circuit, which switched off the current and after cooling, should come in order.

Baym:

That is called the circuit breaker.

Migdal:

Yes.

Hoddeson:

Did you have electricity in your house?

Migdal:

Yes, certainly in Leningrad. There was electricity in the small town too, I suppose. But all these things I have made being in Leningrad.

Hoddeson:

We didn’t find out what your father did.

Migdal:

My father was a drugstore…

Baym:

Pharmacist.

Migdal:

Pharmacist, yes, and my mother was simply very witty and a very clever woman.

Hoddeson:

So there was a kind of a scientific tradition in your family through your father.

Migdal:

Well I think it’s not a scientific tradition, not very scientific.

Hoddeson:

Was anybody in your family connected with science?

Migdal:

No. One of my brothers was connected with technology. He was in technology of bread baking. He invented technology to make the bread cheaper.

Hoddeson:

So you continued school in Leningrad and then went on to the university.

Migdal:

Yes.

Baym:

you must have finished the university in Leningrad.

Migdal:

Yes.

Hoddeson:

And did you study physics there?

Migdal:

Yes.

Hoddeson:

What about earlier?

Migdal:

You see I decided to be a theoretical physicist, I think a year before coming to the university. I published my first small article about a device which can show the constant acceleration in the gravitational field of the earth. It was my first work. And you see it was diffcu1t to attend the university at that time. I came to a physicist who was a very prominent teacher — he was very famous at that time — Professor Khvolson. He wrote five huge volumes about physics.

Baym:

Were these books very influential in Soviet physics?

Migdal:

At that time yes. Now everybody has forgotten about these books.

Baym:

This is about 1930?

Migdal:

It’s about 1927.

Baym:

When did you first begin to learn about quantum theory?

Migdal:

I think in the university.

Baym:

Were there lectures on the subject?

Migdal:

It was lectures by Fock. Besides, there was a group of very active young people, and we studied quantum mechanics, the first book was ACHT VORLESUNGEN UBER WELLENNECHANIK, by Schrodinger.

Baym:

What about the Sommerfeld books, ATOMBAU, and so on?

Migdal:

Yes, they were very influential, but later. The start was by the WELLENNECHANIK.

Hoddeson:

If this was ‘27, then the Soviet Union was not behind at all in learning about quantum mechanics.

Migdal:

No, let me check the year more carefully. Yes maybe it was ‘28 or I had been an assistant of the teacher for a year in ‘27 and in ‘28 I attended the university.

Hoddeson:

So you were actually learning about the forefronts of physics before you entered the university?

Migdal:

No, I knew only the elementary physics — I knew it well, but only the elementary physics.

Hoddeson:

How did you happen to know enough to write a paper?

Migdal:

Because I invented this very simple device to control acceleration — simply a rope with some balls whose distance increased proportionally to the square of the length. So you can control that all balls came at the same time interval in spite of the larger interval of length. That was the idea. I published it in the magazine which is especially for teaching physics and mathematics in school.

Hoddeson:

What was that called?

Migdal:

The title is PHYSICS, MATHEMATICS AND CHEMISTRY IN THE LOWER SCHOOLS. And this person, Khvolson, he read the article and I showed him my invention, for some of them I had patent certificates. So he read all this material and wrote a very good letter to the rector of the university, and they took me in. It was very difficult at that time. It was overfilled and they preferred to take people from working families. I even had a special paper in which it was written that I as an inventor have all the rights of the working people to attend the university. There was such a rule for inventors.

Baym:

When did you first meet Landau?

Migdal:

First I met him — it was a conference — I’m very bad on dates.

Hoddeson:

You worked at the university until about ‘32 or ‘33?

Migdal:

No, there was a stop in my studies; I was working at a laboratory of a plant, making some calculations. I stopped at ‘31, and finished the university ‘36.

Hoddeson:

And between ‘31 and ‘36?

Migdal:

I worked in the plant which was for measurement and there I made my first theory which was checked by experiment.

Hoddeson:

I asked you the question about the dates because I thought it would help you figure out when you met Landau.

Migdal:

Yes.

Hoddeson:

Well, we know that from ‘28 to ‘3l you were at the university. ‘31-‘36, approximately in the measurement plant. And do you remember if, when you met Landau, you were in the measurement plant?

Migdal:

First, I met him at a conference, it was an international conference in Moscow, but I don’t remember the exact time. I met many great physicists and made my first acquaintance with Landau.

Hoddeson:

So somewhere around ‘31 or so.

Migdal:

No, it was before that — much more before that. In ‘40 I came to Landau and he took me to Kapitza’s institute. No, the first meeting was I think about ‘35 and I was very glad because somebody told me that Landau said good words about my work. I simply said to him about things I have been working on. Maybe it was ‘36. And then I met Landau from time to time, It was some interval when I simply worked and then I came to Landau with seven works, I finished seven works. And Landau approved it, and Landau was very satisfied with the work and proposed to me that I work with him. That was the beginning. I think it was maybe ‘38,

Hoddeson:

Before we go on, that conference you mentioned earlier you say was maybe ‘28 or ‘29 in Moscow.

Migdal:

No it was later. I was a student.

Hoddeson:

It’s interesting that you as a young student would go to an international conference.

Migdal:

But I was not invited as a member of the conference. I simply went.

Hoddeson:

You heard talks then?

Migdal:

Yes.

Baym:

I would like to ask about the state of nuclear physics in the Soviet Union in the ‘30’s. What were the problems that were being worked on?

Migdal:

Maybe I can say about my environment. Hoddeson &

Baym:

Yes.

Migdal:

As a post graduate student at that time, it was in ‘36, I attended the Leningrad Physical-Technical Institute, and one of the post graduate students was Berestetskii who later wrote this well-known book about quantum electrodynamics. Then, Pomeranchuk, then Shmushkevitch. It was a good group and all these people were very involved in science and we’d speak only about science, and it was the whole day and the whole night sometimes. The most popular topic was the theory of metals. At that time, every physicist supposed that it was the main and the most important part of theoretical physics, metal theory. Frenkel was the chief of the theoretical department and I blame myself very much, that I didn’t appreciate him enough. It was simply the stupidness of youth because he always made mistakes and that annoyed us because we tried to be very exact and all of this. So we failed to understand that he’s really a very good physicist, with a lot of ideas — very good physicist.

Hoddeson:

Did he have many people around him who got interested through him in working on metals?

Migdal:

I cannot say that, no. He had a very small influence on us, because we had been influenced by Landau, in spite of the fact that Landau had been in Moscow at that time. So we came to Moscow from time to time so speak to Landau. And that’s why I say, that we didn’t appreciate Frenkel enough at that time.

Hoddeson:

Some time ago, I looked a little bit at the development of the quantum theory of solids that went from Pauli to Sommerfeld to Bloch, Peierls and so on. And Frenkel’s papers are of course in that series and very important.

Migdal:

You see, he always made a good contribution in the beginning of some work. He didn’t like to make some exact works. His style was to give ideas. It was his idea about the long mean free paths of electrons in metals. Of course you know that he wrote an article about fission at the same time as Niels Bohr and Wheeler.

Hoddeson:

At the same time?

Migdal:

The same time, yes. Independently.

Baym:

This would be about when?

Hoddeson:

About ‘38.

Migdal:

Yes.

Hoddeson:

That’s fascinating. Perhaps we can talk now about the beginnings of nuclear physics in the Soviet Union and then after that, maybe, about the beginnings of solid state physics or vice versa. (Laughter) gather you got involved first in nuclear physics.

Migdal:

Not exactly. Yes, maybe it’s more exact to say that, because the works which I brought to Landau, they had been in atomic physics and in nuclear physics.

Baym:

Did this include the paper on ionization?

Migdal:

Yes, I came to Landau with this work on ionization on alpha and beta decay, and then there was an article on ionization by neutrons and on neutron scattering in crystals and liquids.

Hoddeson:

Were you in close touch with developments in nuclear physics that were going on in Europe and America in this period?

Migdal:

I think so.

Hoddeson:

Did you get the journals, for example?

Migdal:

Yes. Before the war we had journals. Especially German journals and magazines. At that time maybe they contained the most important papers. Works by Peierls, Bethe —

Baym:

Did you meet any of these people? Peierls, Bethe, Bohr?

Migdal:

I met Peierls at this conference when I first met Landau. It was only once. And later came the war…

Baym:

Were you completely cut off during the war from knowledge of physics and information from the West?

Migdal:

Yes.

Hoddeson:

I understand from our conversation the other day at dinner that in the Soviet Union many physicists did continue to do some of their own work during the war. Landau, for example.

Migdal:

Yes, Yes.

Hoddeson:

What about you? Did you do some of your own work during the war?

Migdal:

Yes. First I did some work in defense. I made some inventions. And then I worked in low energy physics. I remember only one work that was not published.

Hoddeson:

What was that?

Migdal:

It was diffusion in liquid helium 4. It was some kind of, I don’t remember exactly, I simply calculated the movement of some “painted part” in liquid helium due to the zero vibration.

Baym:

I see.

Migdal:

Non-zero vibration because the effect is proportional of course to some power of temperature.

Hoddeson:

We were talking about the war.

Migdal:

Yes,

Hoddeson:

Generally, what one would like to know is how the war affected physics in the Soviet Union. One way to find out is to ask how it affected you. You might also tell us how it affected others.

Migdal:

You see, it influenced us very much, because in spite of the fact that some of us had been working along the same lines it was of course a period of very still scientific life. Towards the end of the war the activity increased. For instance Alikhanian went on an expedition into Yerevan and we started to study cosmic rays. Landau, Pomeranchuk and myself. We made some works in cosmic rays, in the theory of Auger showers.

Baym:

How would you say the war influenced the style of physics after the war? In this country, for example, you see a much greater growth of large institutions doing physics.

Migdal:

Yes, first the development of nuclear physics increased very much. It was some influence of the war. It started before the end of the war, but atomic energy for instance was founded at that time. You see I am afraid I am not the best person for you to…

Baym:

Oh, that’s not true. I myself have learned a lot.

Migdal:

You see, what I would like to say is that the Physical-Technical Institute in Leningrad was an excellent institute at that time.

Baym:

Which were the major centers for physics at that time?

Migdal:

It was in Leningrad, in Kharkov, in Sverdlovsk. All of these institutions were made under the influence of Ioffe, who had a great influence on the early physics in the Soviet Union. It is difficult to find any physicists of my generation who was not connected with Ioffe, or some Institute which was not connected with him.

Baym:

I see.

Migdal:

Artismovich, Kurchatov, all came from Ioffe Institute.

Hoddeson:

When did theoretical physics in Russia divide up into nuclear physics, solid state physics and other specialties?

Migdal:

You see Landau’s idea was that theoreticians should not be devoted to one special part of physics. Of course it’s impossible. But it was his idea that all of his pupils should at the same time do nuclear physics and all other kinds of theoretical physics. For instance I was working in the Atomic Energy Institute and making some theoretical physics in nuclei. At the same time, I made my work in solid state about the influence of the zero vibration on the electron motion.

Baym:

The work in helium?

Migdal:

No, I mean not in helium. I mean in solid state. It was after Frohlich’s work. I solved the Frohlich problem exactly, not supposing that the interaction is small. I was told by Bardeen that this work was important for him.

Baym:

Yes, this work on the electron-phonon interaction was very influential in the United States.

Migdal:

I will try to remember at what time I started my idea that the zero vibration is the source of superconductivity. My idea was that if electrons would be very close, so they should satisfy the Van Leeuwen theorem, there is no diamagnetism. But the only reason why electrons are not a closed system in metals is the zero vibration. So that was the starting point and I was absolutely sure that zero vibration is the reason for superconductivity.

Baym:

This was when?

Migdal:

It was five years before the isotope experiment.

Hoddeson:

So 1950.

Migdal:

Yes, it was 1950. Maybe even earlier. I started earlier, yes. I even wrote an article about that. If I had published this article maybe the experiment would have come earlier. But Landau was against my publishing this article. What he said was it was not finished. “You should try to make something positive, not simply to say…” Even now I have this, yellowed by time, paper in which all this had been written. And so everybody in the Soviet Union knew I was dealing with this idea about zero vibration and I try to obtain the spectra of electrons which uses zero vibration and I have made this work you mentioned just because I had been working in connection with electron motion and zero vibration, And then when the isotope experiment came, it was winter, and it was very cold in Moscow, extremely cold, and Pomeranchuk was wearing a hat at that time, and when he came across me in the street, he saw me for the first time after this isotope experiment, he said “Arkady” and put off the hat, (Laughter).

Hoddeson:

How did you hear about the isotope experiment?

Migdal:

It was published.

Hoddeson:

I guess you must have been pretty closely involved with the Ginsberg-Landau work

Migdal:

No, only in a negative sense. Because when I have made this work about the jump in the momenta distribution in Fermi liquid in this work there was a statement that the average value of momenta density cannot exceed one, for a fixed momentum. But when I showed Landau, Landau said “But how does it work?” “It contradicts to our equation for Ψ.” You know the function which corresponds to the charge of density?

Baym:

Yes.

Migdal:

But of course it’s not an electron density, it’s the pair density. But at that time he didn’t understand that they were speaking about pairs. So he was very afraid. But then he said, “But I think nevertheless this should be right.”

Baym:

While we’re on this question, the story is told about Abrikosov’s ‘57 paper on the type II superconductors, that Landau did not let him publish this for many years. What are your recollections?

Migdal:

But you see I was far from this. It was the time that I was involved in my work in Atomic Energy Institute and I came not very often to Landau Institute so this part of the activity I simply missed. At that time I was not so interested in superconductivity.

Hoddeson:

And then what did you do?

Migdal:

I made some work in nuclear physics and maybe, yes, the collective excitation in nuclei, the giant resonance.

Baym:

The giant resonance was much earlier though.

Hoddeson:

It was ‘44.

Migdal:

‘44, yes. You know better than me. I mean some further development.

Baym:

Was that worked on during the war?

Migdal:

It was published in ‘44, but it was done rather earlier, I think the rough idea was very early, but maybe it was during the war.

Baym:

Were there Soviet experiments?

Migdal:

No. And then I started to work in the line of application of Feynman’s methods to many body theory. I started to apply Fermi liquid theory to nuclei, a long period because this work needs computers and we had no computers at that time. We were only starting with computers at that time so it was a difficult time.

Baym:

I would like to ask which books from the West were particularly influential in the ‘30’s and ‘40s.

Migdal:

In quantum mechanics, I think the Sommerfeld book.

Baym:

What about the Bethe review article on nuclear physics in 1935?

Migdal:

Yes, of course. That had been very influential.

Baym:

You had read this.

Migdal:

Yes. It was very important at that time, yes, of course. Then the book of Heitler on quantum electrodynamics was most influential. It was one of the books we loved.

Baym:

Did Landau read these also?

Migdal:

No, he would like to listen to some of these things. He was listening very attentively. But he didn’t read any of them.

Baym:

What about the book by Mott and Jones? The book on metals and alloys.

Migdal:

Yes. I think this book for me was not very influential. But the book about scattering theory...

Baym:

This is Mott and Massey.

Migdal:

Mott and Massey, yes. This book was influential, in my circle.

Hoddeson:

While we’re mentioning that Landau read much, I would like to ask, how did Landau work? Did he spend most of his time talking to people; did he spend most of his time alone?

Migdal:

I think… you see, very often he worked speaking with people. You put some question to him and he came to the blackboard and made a theory. And then he continued to work lying on the sofa. In writing his papers he usually wrote not along the sheet but sideways. (Laughter).

Hoddeson:

The other day you compared Landau to Fermi.

Migdal:

Yes. But you see I have known Fermi only through some stories which have been told by Bruno Pontecorvo. I have a feeling they were very alike in their kind of thinking; in the way to turn physical ideas into formulas. I can tell you something about Landau. You see, first, he had an idea that you should absolutely oversimplify the problem, from the beginning. It’s a good idea. Of course it’s better to put in more difficulties later when you understand the starting point. So he said about himself, “I am a genius of trivialization.” (Laughter) Then of course he had been on an extremely high level of mathematics, a really professional high level of mathematics. You know one of our best mathematicians, Gel’fand, he is a member of many academies. It’s absolutely an international mathematical first class level, he said after working with Landau for some time. Landau disliked all mathematical things which are not effective; all the theorems which are very important for mathematics but useless for physics. Existence, theorems, formal proofs. And some kinds of tricky considerations about possible functions because physicists always have functions of a very simple type. So Landau disliked this, but he knew all effective methods of mathematics and he used them as an expert.

Hoddeson:

So he was very practically oriented.

Migdal:

Yes, in this sense practically oriented, yes.

Hoddeson:

Was he in close touch with experimentation that was going on in physics in the Soviet Union?

Migdal:

I think his only touch was when he came once, like Pauli. You know that when Pauli came to some laboratory, all devices are spoiled afterwards. (Laughter) But he liked very much to know from experimentation, from the experimenters, to have some review of the experiments. Without details, without devices, but simply the experimental results. He liked it very much.

Hoddeson:

Did he spend a good part of his working time talking to experimenters?

Migdal:

No, not very much. He liked simply to listen to some review at a seminar. To know in one hour some wide region of experimental data with possible explanations.

Hoddeson:

Was there a very active seminar at Landau’s institute?

Migdal:

Yes. It was very interesting.

Baym:

Tell us a little bit how it was organized?

Migdal:

It was at an exact time.

Hoddeson:

Once a week? Twice a week?

Migdal:

Once a week. Then somebody reported on some magazine, THE PHYSICAL REVIEW. The whole volume of THE PHYSICAL REVIEW. All theoretical works which are inside, and all experimental work.

Baym:

About what year did this begin?

Migdal:

It was I think… maybe just before the war. And then just after the war, too. Sometimes it was reports about some special topics. Besides that, to know the literature, everyone from Landau’s environment was obliged to make a review of some issue of some magazine,

Baym:

Who decided this? Would the students or the other people do it themselves, or would Landau divide it up?

Migdal:

No, Landau directed it and there was a cue, I was excluded because it’s difficult to force me to do what I don’t want to do.

Hoddeson:

But you attended these every week.

Migdal:

Yes. I attended every week, of course. It was very interesting. It was impossible not to attend. I did it every week. I made talks but not reviews of the issues.

Hoddeson:

About how long were the meetings?

Migdal:

They were two hours. One hour, then ten minutes talking during the break. It was very interesting to listen to the reaction of Landau to articles. Sometimes he just made a theory coming to the blackboard. Sometimes it was the starting point for some theory; sometimes he asked somebody to make calculation, to understand this, you know… and so on. I will tell you a story. One theory which was not published, because it was difficult to publish articles at that time: the idea was that alpha decay should be increased by the surface vibrations. You have the vibrations and the alpha particle would wait for the moment when the nucleus would have a good shape to go away. I had made this theory. But I was sure that Landau would be against the theory if he knew that it was me. So I pretended that I am telling about a last work by Bloch.

Baym:

Felix?

Migdal:

I suppose it is Felix. After Landau approved the theory, I said you know I have made a little joke. It’s me who made the theory. (Laughter)

Hoddeson:

One last question about the seminar. How big was it? How many people would go?

Migdal:

More or less, practically all theorists in Moscow. So I think it was 20 or 30 people. Something like that. I would like to tell you about the practical joke… It was a letter of Pauli…You don’t know? Very interesting. It was a letter. All physicists in Moscow were very excited because it was known that Pauli wrote a letter to Weisskopf about Heisenberg’s new theory, the theory of elementary particles.

Baym:

This was in the ‘50’s?

Migdal:

Yes. And everybody was waiting for this letter because somebody told that it might be possible to ask Weisskopf to send a copy of this letter to Russian physicists. And once, Pontecorvo and me, we decided to make this letter. We worked very hard, the whole evening. And you see, the idea was to pretend it’s the letter of Pauli and fool Landau. It’s not so easy a problem. But nevertheless we wrote a good letter. Pontecorvo invented a very good experiment which was put in this letter, and Pauli said it is a pity I don’t believe the theory. It is a pity because this and this experiment is easy to explain; using this theory. And the end was the following, so I am skeptical about this theory. But Heisenberg is more optimistic. But you see it’s the real end of the real letter so we guessed the real end. A few months later it came. I was known as a man who can make some practical jokes. So I should be absolutely non-connected, Pontecorvo gave this letter to somebody else. This man gave the letter to the man who at that time had been the chief of Dubna Institute and the director of the Institute gave the letter to old Kapitsa and old Kapitsa gave the letter to Landau. And before the seminar, Landau phoned me and said you should be on time at the seminar, because we will discuss the letter by Pauli. And then the seminar started with reading the letter in English. Then somebody asked for it to be translated. Then the discussion starts and it was a very hot discussion, and Pomeranchuk was very excited and he said I was absolutely sure it was the wrong theory. It’s good, yes, I absolutely agree with Pauli and so on. Then there was a stop. It was a whole hour. And then during the break Okun invented a very tricky explanation of how this experiment can be explained without Heisenberg’s theory. And the second hour started with a talk of Okun. And then after the discussion stopped, I said in an innocent voice, you see, it is strange that the first letters of the sentences of this letter make a Russian word. By that moment some physicists rewrite the letter to make reports in Kharkov, Kiev or somewhere else. And so Lifschitz read, “duraki,” That is, “fools.”

Baym:

That was the giveaway.

Migdal:

Landau was very satisfied. He very much liked every time when I made some joke. Really liked it. Baym; Does that letter still exist?

Migdal:

Yes, I am sure.

Baym:

That’d be wonderful to see sometime.

Migdal:

Yes, maybe I can find it among my papers. But of course I think there are many copies.

Baym:

That’s wonderful.

Hoddeson:

Take good care of your papers… they are important for the history of science, Thank you very, very much.