Scope and Content of Collection
Title: Paul Sophus Epstein papers,
Date (inclusive): 1898-1966
Collection number: Consult repository
Epstein, Paul Sophus, 1883-1966
17.25 linear feet
California Institute of Technology. Archives.
Pasadena, California 91125
Abstract: Epstein was a physicist at California Institute of Technology from 1921-1953; he taught
advanced courses in mathematical and theoretical physics. Collection includes general and family correspondence;
personal and biographical material; notebooks; manuscripts; class notes by a Caltech student; books, mostly
technical and in Russian; reprints of Epstein's writings.
The collection is open for research. Researchers must apply in writing for access.
Copyright may not have been assigned to the California Institute of Technology Archives. All requests for permission to publish
or quote from manuscripts must be submitted in writing to the Head of the Archives. Permission for publication is given on
behalf of the California Institute of Technology Archives as the owner of the physical items and is not intended to include
or imply permission of the copyright holder, which must also be obtained by the reader.
[Identification of item, box and file number], Papers of Paul Sophus Epstein. Archives, California Institute of Technology.
The Paul Epstein collection was given to the Caltech Archives in 1977 by his widow, Mrs. Alice Epstein.
Epstein was the first European-trained physicist to come to Caltech on a permanent basis. Recruited by Robert A.
Millikan in 1921, he was one of a generation of prominent mathematical physicists who laid the foundations for modern
atomic physics. Having studied and worked in Moscow, Munich, Zurich and Leyden before settling permanently in the
United States, Epstein had wide personal and scientific contacts.
Epstein was born in 1883 in Warsaw to a moderately well-to-do Jewish family. He grew up in Minsk and later
attended the Imperial University of Moscow, where he received B.S. and M.S. degrees. Foreseeing the Russian Revolution,
he left Moscow to continue his studies in theoretical physics in Munich under Arnold Sommerfeld. His early research was in
the theory of electromagnetic waves, particularly the theory of their diffraction. He received his Ph.D. at the outbreak of
World War I, with the thesis "Über die Beugung an einem ebenen Schirm unter Berücksichtigung des Materialeinflusses"
("Diffraction from a Plane Screen...," 1914).
Though held as a civil prisoner in Germany during the war, he nonetheless continued to do research in the problems
of the quantum theory of atomic structure based on classical mechanics. An important paper from this period is "Zur
Theorie des Starkeffektes" ("The Theory of the Stark Effect,"
Ann. der Physik 50, 1916). In 1919, with the end of the war,
Epstein was able to take up an appointment as Privatdocent at the University of Zurich. Upon applying for this position he
wrote a paper (Habilitationsschrift) applying the quantum theory to optics, which caused a stir ("Anwendungen der
Quantenlehre in der Theorie der Serienspektren,"
Die Naturwissenschaften 17, 1918).
As early as 1910 or 1911, Epstein had become interested in pyschoanalysis as a remedy for depression and
associated physical symptoms. This interest eventually led to a meeting with Freud in Switzerland, circa 1911-12. Later
Epstein was instrumental in founding the Los Angeles Institute of Pyschoanalysis. His knowledge of and practical
involvement in this field lasted throughout his life.
Having lost most of his inherited means during the war and in need of a paying position, Epstein went to Leyden in
1921 to become assistant to H. A. Lorentz. There he met Millikan, who invited him to come to the newly created California
Institute of Technology. Epstein arrived in Pasadena on a blistering September day in 1921, knowing very little English. He
was to remain at Caltech until his retirement in 1953 at the age of 70. During this time he taught substantially all of the
advanced courses in mathematical and theoretical physics.
At Caltech Epstein's research continued on Bohr's form of the quantum theory, which culminated in 1922 with the
publication of four papers, three in the
Zeitschrift für Physik and one in
The Physical Review. Later he participated in the
development of quantum mechanics. An important paper in this connection appeared in the
Physical Review in 1926: "The
Stark Effect from the Point of View of Schrödinger's Quantum Theory." In 1930, Epstein was elected to the National
Academy of Sciences.
Epstein's range of interests was wide. He devoted considerable attention to borderline problems involving physics
and other sciences, for example, his papers "Zur Theorie des Radiometers" (1929), "Reflection of Waves in an
Inhomogeneous Absorbing Medium" (1930), and "On the Air Resistance of Projectiles" (1931). He wrote two important
articles on general subjects outside of physics, both published in the Los Angeles literary/philosophical journal
Frontiers of Science" (June, 1935) and "The Uses and Abuses of Nationalism" (November, 1935). He also maintained a
number of literary and artistic contacts, including Upton Sinclair.
Although not a Zionist, Epstein was deeply interested in Jewish affairs. He was a friend and supporter of the
mathematician Abraham Fraenkel, a longtime resident of Jerusalem, who played a major role in the organization of
secondary and advanced education in Israel. Epstein was active for many years in the Friends of the Hebrew University of
Jerusalem and was President of the Southern California Chapter.
After his retirement from Caltech, Epstein served as a consultant to several large industrial firms. Among the many
reports written by him at this time, especially significant is his "Theory of Wave Propagation in a Gyromagnetic Medium"
Reviews of Modern Physics 28, 1956).
Paul Epstein died at his home in Pasadena on February 8, 1966, at the age of 83.
Scope and Content of Collection
The Paul Epstein collection contains materials spanning the period from Epstein's high school days in Minsk,
beginning around 1898, up to shortly before his death in 1966. Included is general and family correspondence; personal and
biographical material; notebooks containing a variety of subject matter; a large number of manuscripts, including articles,
lectures and miscellaneous writings on both technical and nontechnical matters; a set of class notes by a Caltech student;
books, mostly in Russian and of a technical nature; and a large quantity of reprints of writings by Epstein himself. Epstein's
extensive collection of reprints by others has been preserved separately from his papers.
His correspondence appears in Russian, German, and English. Important individual correspondents include A.
Berliner, N. Bohr, M. Born, P. Ehrenfest, A. Einstein, Sigmund Freud, G. Jaffe, A. Lande, M. von Laue, H. Lorentz, R.
Oppenheimer, M. Planck, E. Rutherford, E. Schrödinger, A. Sommerfeld, and H. Weyl.
The following terms have been used to index the description of this collection.
Berliner, Arnold, 1862-1942
Bohr, Niels Henrik David, 1885-1962
Born, Max, 1882-1970
Ehrenfest, Paul, 1880-1933
Einstein, Albert, 1879-1955
Freud, Sigmund, 1856-1939
Jaffe, G., 1880-1965
Lande, Alfred, 1888-1975
Lorentz, H. A. (Hendrik Antoon), 1853-1928
Millikan, Robert Andrews, 1868-1953
Oppenheimer, J. Robert, 1904-1967
Planck, Max, 1858-1947
Rutherford, Ernest, 1871-1937
Schrödinger, Erwin, 1887-1961
Sommerfeld, Arnold, 1868-1951
Von Laue, Max, 1879-1960
Weyl, Hermann, 1885-1955
California Institute of Technology
Los Angeles Institute of Psychoanalysis
Physics--Study and teaching