Paul Ehrenfest

Ehrenfest, Paul 

Born Jan. 18, 1880, in Vienna; died Sept. 25, 1933, in Amsterdam. Dutch theoretical physicist. Student of L. Boltzmann.

Ehrenfest graduated from the University of Vienna in 1904; he then moved with his wife, the Russian physicist T. A. Afanas’eva-Ehrenfest, to Russia. Beginning in 1912, he was a professor at the University of Leiden (the Netherlands). His principal works dealt with the substantiation of statistical mechanics, quantum theory, relativity theory, and the theory of phase transitions. Ehrenfest developed (1916) the method of adiabatic invariants in quantum theory. He formulated (1927) the theorem of the average values of quantum-mechanical quantities (Ehrenfest theorem). He also derived (1933) the Ehrenfest relations. Ehrenfest exerted a considerable influence on the development of theoretical physics in Russia and the Soviet Union. He was a foreign member of the Academy of Sciences of the USSR (1924).

WORKS

Collected Scientific Papers. Amsterdam, 1959.
In Russian translation:
Otnositel’nost’; Kvanty; Statistika. Moscow, 1972.

REFERENCES

Frenkel’, V. Ia. Paul’ Erenfest. Moscow, 1977.
Klein, M. J. Paul Ehrenfest, vol. 1. Amsterdam–London, 1970.