23 Facts About Paul Ehrenfest


Paul Ehrenfest was an Austrian theoretical physicist, who made major contributions to the field of statistical mechanics and its relations with quantum mechanics, including the theory of phase transition and the Ehrenfest theorem.


Paul Ehrenfest bonded with Albert Einstein on a visit to Prague in 1912 and became a professor in Leiden, where he frequently hosted Einstein.


Paul Ehrenfest was born and grew up in Vienna to Jewish parents from Lostice in Moravia.


Paul Ehrenfest excelled in grade school but did not do well at the Akademisches Gymnasium, his best subject being mathematics.


Paul Ehrenfest majored in chemistry at the Vienna Institute of Technology, but took courses at the University of Vienna, in particular from Ludwig Boltzmann on his kinetic theory of thermodynamics.


At the time, it was customary in the German-speaking world to study at more than one university, and in 1901, Paul Ehrenfest transferred to University of Gottingen, which until 1933 was an important centre for mathematics and theoretical physics.


Paul Ehrenfest published an extensive obituary in which Boltzmann's accomplishments are described.


Together with his wife, Paul Ehrenfest worked on it for several years; the article was not published until 1911.


Early in 1912, Paul Ehrenfest set out on a tour of German-speaking universities in the hope of a position.


Paul Ehrenfest visited Berlin where he saw Max Planck, Leipzig where he saw his old friend German mathematician Gustav Herglotz, Munich where he met German theoretical physicist Arnold Sommerfeld, then Zurich and Vienna.


Einstein recommended Paul Ehrenfest to succeed him in his position in Prague, but that did not work out.


Sommerfeld offered him a position in Munich, but Paul Ehrenfest received a better offer; at the same time there was an unexpected turn of events.


In October 1912, Paul Ehrenfest arrived in Leiden, and on 4 December, he gave his inaugural lecture, Zur Krise der Lichtaether-Hypothese.


Paul Ehrenfest remained in Leiden for the rest of his career.


Paul Ehrenfest maintained close contact with prominent physicists within the country and abroad, and invited them to visit Leiden University and give a presentation in his lecture series.


Paul Ehrenfest was an outstanding debater, quick to point out weaknesses and summarize the essentials.


Paul Ehrenfest's classes were small, and he made an effort to get to know students who made use of the reading room.


Paul Ehrenfest was not merely the best teacher in our profession whom I have ever known; he was passionately preoccupied with the development and destiny of men, especially his students.


Paul Ehrenfest's assistants included Yuri Krutkov, Viktor Trkal, Adriaan Fokker, Paul Epstein, and Gregory Breit.


Paul Ehrenfest held ambivalent views on science, technological progress, and cultural and social issues.


Paul Ehrenfest's publications are renowned for clarity, by solving paradoxes or by providing clearer descriptions, or are inspiring by posing melliferous questions.


Paul Ehrenfest made major contributions to quantum physics, including the theory of phase transitions and the Ehrenfest theorem, which states that expectation values of a quantum system follow classical mechanics.


Paul Ehrenfest's name is given to the Ehrenfest paradox, an apparent paradox in relativity still discussed today, to the Ehrenfest model, and to Ehrenfest time, the time characterizing the departure of quantum dynamics for observables from classical dynamics.