Biography Paul Erenfest

Born in Vienna, worked in St. Petersburg, contributed to the development of theoretical physics in Russia, with the Netherlands. Proceedings on thermodynamics, statistical mechanics, theory of relativity, quantum theory. Introduced the concept of phase transitions of the 2nd kind. The St. Petersburg period after graduating from the University in Vienna and the defense in the ledwig Bolzman, the dissertation, together with his wife, Tatyana Alekseevna Afanasyeva, they met in Gettingem, where she came from Petersburg to study mathematics, and their little daughter also Tatyana, who, in the style of scientific traditions of the young cheerful family of scientists, was called "those -" those The touch "moved to Petersburg.

The situation in physical science in Russia of that time could hardly be called brilliant. Of course, there were wonderful scientists, but if we talk specifically about St. Petersburg physics, we have to admit that it was at the provincial level. In many cases, the work came down to the repetition of experiments done in European laboratories. And at this time, a new era came to replace the classic - non -northern and non -affiliate - the era of physics.

In such transitional moments of science, the role of conductors of new ideas becomes especially important, and Erenfest can be called one of the most ardent and talented of them. In St. Petersburg, he began to teach at the Polytechnic Institute, but his status did not become stable. The slowness of the bureaucratic machine sometimes manifested even somewhat comical. So, when the official who made a residence permit from Erenfest, that he “does not belong to any faith”, he said thoughtfully: “Think about which cemetery we will bury you if you die?!

In order to find a degree, more precisely, a document about its presence, according to the then, according to the then, not for one thing. Erenfest, but for a number of his young colleagues, these exams, moreover, in the absence of a clear program, demanded a huge cost of labor and time and really torn off the research scientific work. Although his colleagues told Erenfest that for him this is just a proof that no one doubts his qualifications and is not going to examine him seriously, the conscientious Pavel Sigismundovich called Erenfest in Russia began to study a lot of works.

But the case was moving very slowly: often studies were transferred to independent creativity, original publications appeared, but the exams were moved away for an indefinite time. There was another, much more important reason for delays. The fact is that Erenfest gave a lot of time and effort to the “home seminar” that he created together with his wife, where a group of young at that time of St.

Petersburg physicists got the opportunity to get acquainted with the latest achievements of science. Pavel Sigismundovich was an ardent and brilliant popularizer of new ideas. In addition, he had a rare critical talent, which made such seminars with events that had a great influence on the further development of physics not only in St. Petersburg, but throughout Russia. But, being a person of an active life position, Erenfest could not limit himself only to physics.

When, in protest against the reactionary actions of the Minister of Casso, a rather significant group of professors left Moscow University, including P. Lebedev, Erenfest publicly expressed his sympathy for the protesters. This, of course, did not improve the attitude of officials towards a person who "does not belong to any faith," and did not bring him the receipt of the position of a professor, or a privat-Document.

I had to think about a reliable place of work again. Leaving Petersburg with regret, Erenfest and his family went to look for refuge and work in Europe. Professors in Leiden's searches were far from simple. Erenfestes moved from one city to another, and, perhaps, the only plus in all this was communication with many colleagues. In Berlin, he was accepted by Max Planck.

But the main thing is that he met, and soon made friends with Einstein. Einstein took a lively participation in the fate of Erenfest and, apparently, played a decisive role in it. In any case, it seems likely that it was Einstein's high opinion about Ehrenfest that became one of the most important reasons why the great Kh. Lorenz, deciding to leave the department at Leiden University, chose Erenfest with his successor.

Erenfest perceived the news that struck him as the greatest and not deserved by him. Until the very last moment, until the ceremony of joining the professor’s post, he could not believe that such happiness is possible. In addition, despite the sedative words of the great Lorentz, he painfully doubted whether he should insist that this place was given to the more worthy, as it seemed to him, Peter Debai.The great teacher Erenfest, perhaps, was a greater teacher and educator of young physicists than the theoretician-researcher.

In any case, he himself thought so, and this thought, which over time strengthened in it, became the cause of more and more severe experiences. He felt more and more clearly that the creative principle in it was inferior to the beginning of the critical. Erenfest ceased to believe that he would still be able to create something significant in physics. He always strove for clarity, but in quantum mechanics, although he belongs to a number of important provisions to recall at least the “Erenfest theorem”, which allows him to explain the ratio between the statistical, probabilistic laws of the micromy and the determinical laws of Macrome, with the abandonment of the classical clarity of the description of phenomena, it was difficult for him to come to terms.

But here it is appropriate to recall the story of the back. Two young at that time of the student of Erenfest, Samuel Gaudsmit and George Ulenbek, came to the conclusion that the electron is, as it were, a kind of microscopic top - he has his own moment of the number of movement. Erenfest captured, but this idea alerted, and he decided to turn to the Patriarch of theoretical physics - to the Lorentz.

He reacted with the usual benevolence to the work of young colleagues, but after some assessments he indicated that to explain the value of the moment of the number of movement, one had to attribute the electron or unacceptable size, or obviously unrealistic rotation speeds. If you represent the electron as a ball of radius R and mass M, rotating so that its surface has speed V, then its moment of the amount of movement of the order R.

But the spin, that is, the opinion of the Lorentz could put an end to all this activity, but Erenfest, although he did not share the opinions of Wolfgang Pauli, who believed that the spin is simply a new quantum number, which is not essential for electron statistics and not Allowing a visual interpretation in the spirit of classical mechanics, he began vigorously seeking the publication of the work of his two students.

Although he did not even manage to enlist the support of Niels Bor, and work in was published, of course, without the surname of Erenfest and received worldwide recognition. Erenfest has developed the main scientific achievements of the adiabatic invariant method in formulated the Erenfest Theorem on the average values ​​of quantum -mechanical quantities. The thermodynamic relationships binding the macroscopic characteristics of the phase of the thermodynamic system at the phase transition of the second kind during the transition of liquid helium to a super -wearing state, the ferromagnetics to the paramagentic, and the connection with Russia, Erenfest for many years, turned out to be divorced from his Russian friends.

Only in Leiden came the first letter from St. Petersburg. Erenfest developed violent activity to help Russian physicists at difficult time for them. There was a need for everything: in literature, in scientific equipment and, perhaps, most in communication. Erenfest’s troubles were crowned with noticeable successes. Already in the first two physicists from Russia - Dmitry Sergeyevich Rozhdestvensky, and followed by Abram Fedorovich Ioffe - received the opportunity to visit not only Leiden, but also a number of other scientific centers in Europe.

And the currency for trips of colleagues from Russia managed to exhale Erenfest. He also a little later, in, in Russian physicists and even for some time he examined the option of moving to Kharkov to lead the work of theorists at the recently created physico and technical institute. Erenfest refused this plan, and one of the reasons for this was the fact that he discovered, that Russia's theorists had already completely left the age of student and did not need his instructions.

Perhaps this also strengthened in the soul of Erenfest woeful thoughts about his uselessness for physics. In the days of youth, Erenfest had seemingly an inexhaustible margin of cheerfulness. This is how one of our most prominent physicists recalled him, A. Joffe: “And although in his life the sky was not always cloudless, he would have thought, could be considered a happy person.

He had a fiery beloved work, a wonderful wife, three of their four children, alas, was very different, but everyone had undoubted abilities. He occupied a prominent and honorary position. "Einstein about Erenfest, but what was written by one of his closest friends, Albert Einstein, after it became known that Paul Erenfest committed suicide:" We met 25 years ago.

He visited me in Prague, where he came directly from Russia. In a few hours, we became insisting friends, as if our aspirations and dreams were the same.

We were connected by close friendship, which continued until his death. His greatness was the extremely well -developed ability to capture the very essence of the theoretical concept and to free the theory from a mathematical outfit so that the simple idea that was based on it was manifested with all clarity. This ability allowed him to be an incomparable teacher.For the same reason, he was invited to scientific congresses, because he always made grace and clarity in discussions and some of his expressions could be interpreted as arrogant, but his tragedy consisted precisely in almost painful unbelief.

He constantly suffered from the fact that his critical abilities ahead of constructive abilities. The critical feeling was robbed, so to speak, a love of the creation of one’s own mind even before it arose. Soon after our first meeting in Erenfest’s career, a decisive turn occurred. Our highly respected mentor Lorenz, wanting to move away from the systematic lecture at the university and seeing an inspired teacher in Erenfest, recommended him as his successor.

Before him, still young, a wonderful field of activity opened. He was not only the best professor of the people of our profession, whom I knew, but he was passionately occupied by the formation and fate of people, especially his students. Understand others, to gain their friendship and trust, to help someone who was suppressed by an external or internal struggle, to encourage young talents - all this was his true vocation even more than deepening scientific issues.

In Leiden, students and colleagues loved and respected him. They knew his absolute devotion to the case of teaching and constant readiness to come to the rescue. Should he be a happy person? In fact, he was unhappy than all those who were close to me. The reason was that he did not feel at the level of the high task that was supposed to fulfill. What helped him universal respect! He was constantly tormented by an objectively unreasonable sense of imperfection, which often deprived him of spiritual peace, so necessary in order to conduct research in recent years, this state has become aggravated due to the surprisingly rapid development of theoretical physics.

It is always difficult to teach things that you yourself do not approve with all your heart: it is doubly difficult to fanatically pure soul, for which clarity is everything. To this was added an ever -increasing difficulty in adapting to new ideas, a difficulty that always lies in wait for a person who crossed over fifty. I don’t know how many readers of these lines are able to understand this tragedy.

But still she was the main reason for his life.