Gordon, Walter

(b. Apolda, Germany. 3 August 1893: d. Stockholm, Sweden, December 1940)

theoretical physics.

After studying at the University of Berlin, Gordon obtained the Ph.D. there in 1921. He remained until 1929, when he became Privatdozent—and later associate professor—at the University of Hamburg. He lost his position there, like other professors of Jewish origin, in the spring of 1933. He became a member of the Institute of Mathematical Physics at the University of Stockholm in the fall of the same year. Through a grant from the Rockefeller Foundation and contributions from organizations for refugee aid and some private sources, he and his wife obtained a meager living. Poor conditions for science at the University of Stockholm, together with a general lack of understanding of existing German political conditions, prevented his obtaining a regular position.

Gordon’s thorough mathematical foundation led him to rigorous solutions of important problems of quantum theory. He did not produce many writings, but his publications are of high quality. Some of his results were obtained by others about the same time, because of the intense development of quantum mechanics during the 1920’s.

Soon after Erwin Schrödinger’s publication of his first papers on wave mechanics in 1926, Gordon made several important contributions to the relativistic generalization of nonrelativistic quantum mechanics: the current-density vector of the scalar wave equation, and the quantitative formula for the Compton effect. That these results were not applicable to the electron—as was generally believed at that time—but to particles obeying Bose statistics, which, however, were discovered later, does not detract from the quality of this work. Soon after the appearance of Dirac’s theory of the electron early in 1928, Gordon published two papers containing important contributions to this theory.

In the first paper he gave a rigorous treatment of both states of the Dirac equation in a Coulomb field: the bound states with the characteristic energy values given by the formula, derived earlier by Sommerfeld (before quantum mechanics and spin were known), and the continuous states, his treatment of which was of methodological importance. He returned to the continuous states, but in the nonrelativistic case, in a somewhat later paper containing a thorough study of the continuous wave functions in a Coulomb field, which was important for the problem of particle scattering.

In his next paper Gordon showed that the currentdensity vector, given by Dirac, can be split into two parts, one being formally equal to the one he himself had derived for the scalar equation—being, so to say, its kinematic part—while the other is connected with the spin of the electron. In his last paper, presented at the Congress of Scandinavian Mathematicians at Stockholm in 1934, he returned to a similar but more general problem, the possible states of a Schrödinger type wave equation in a multidimensional space, applying it to the probability of a quantity given as a function of the momenta and the coordinates and ending the paper with establishment of the integral equation for the states in a Coulomb field as functions of the momenta.

During almost all of his stay in Sweden, Gordon participated eagerly in the seminars at the Institute of Mathematical Physics, to which his erudition, not merely in physics and mathematics, and his caustic but friendly humor gave a characteristic touch. He also gave lectures, among them a valuable course in group theory.

But Gordon’s forced exile, taking him from the congenial and inspiring circle at the Hamburg Institute of Physics, and the uncertainty of his future brought an end to his creative powers. Early in 1937 his health declined, and inoperable stomach cancer was diagnosed. Good medical treatment and the care of his wife enabled him to live a reasonably normal life until the last months of 1940.

BIBLIOGRAPHY

Gordon’s writings include “Der Comptoneffekt nach der Schrödingerschen Theorie,” in Zeitschrift für Physik, 40 (1927), 117–133; “Die Energieniveaus des Wasserstoffatoms nach der Diracschen Quantentheorie des Elektrons,” ibid., 48 (1928), 11–14; “Über den Stoss zweier Punktladungen nach der Wellenmechanik,” ibid., 180-191; “Der Strom der Diracschen Elektronentheorie,” ibid., 50 (1928), 630–632; and “Eine Anwendung der Integralgleichungen in der Wellenmechanik,” in Comptes rendus du huitiéme Congrès des mathématiciens scandinaves tenu à Stockholm août 1934 (Lund, 1935), pp. 249–255.

On Gordon or his work, see Bertrand Russell, Introduction to Mathematical Philosophy (London-New York), trans. into German by E. J. Gumbel and W. Gordon as Einführung in die mathematische Philosophie (Munich, 1930), with a foreword by David Hilbert.

Oskar Klein