,
Werner Heisenberg,
George S. Monk,
Paul Dirac,
Carl Eckart,
Henry Gale,
Robert Mulliken,
Friedrich Hund,
Frank C. Hoyt. Chicago 1929.
University of Chicago Returning to the United States in 1928, Eckart was appointed assistant professor in the physics department at the
University of Chicago, where he continued his work on quantum mechanics for another 14 years. Noteworthy was a paper co-authored with
Helmut Hönl, who received his doctorate under Sommerfeld in 1926; the paper, on the foundations of quantum mechanics, dealt with the role of group theory in quantum dynamics in monatomic systems and comparisons of the nuclear theories of
Werner Heisenberg and
Eugene Wigner. During this period, Eckart developed his formulation of the
Wigner-Eckart theorem – a link between symmetry transformation groups applied to the Schrödinger equation and the laws of conservation of energy, momentum, and angular momentum. The theorem is particularly useful in
spectroscopy. With
F. C. Hoyt, Eckart translated Heisenberg's book on the physical principles of quantum mechanics. During the 1934–1935 academic year, Eckart took a sabbatical at the
Institute for Advanced Study in
New Jersey, as he also did in the academic years 1952-1953 and 1960–1961. However, in 1941, Eckart withdrew from the Committee because of his anti-atomic bomb sentiments. Also notable during this period are his papers on the thermodynamics of irreversible processes.
University of California, San Diego With the entry of the United States into
World War II in December 1941, there was increased incentive for the scientific community to participate in the war effort. Axis submarines were exacting a toll on allied shipping, and university scientists were being approached by the U. S. Navy concerning optical and acoustical detection of submarines. B. O. Knudsen, director of the newly formed University of California Division of War Research, and his associate L. P. Delsasso approached Eckart for help. Eckart (an associate professor) took leave from the University of Chicago to work on the problem, thus beginning his 31-year stay in California. From 1942, he was assistant director of the Division of War Research, and eventually he was director, a position he held until 1946. In 1946, Eckart officially resigned his position at the University of Chicago to become a professor of geophysics at the
Scripps Institution of Oceanography of the
University of California, San Diego (UCSD), a position he held until 1971. In 1946 he also became the first director of the Marine Physical Laboratory (MPL) of the University of California. The MPL was founded by Eckart,
Roger Revelle, and Admiral Rawson Bennett to conduct geophysical research of common interest to the academic and naval communities. In 1948, the MPL became an integral part of the Scripps Institution of Oceanography, and Eckart served as the fourth director of Scripps until 1950. Eckart contributed to geophysics by linking theoretical hydrodynamic exercises to actual physical properties of water. In the following decades he did research on thermal layering in the ocean and atmospheres on which he wrote a book, the transmission of sound in the sea, turbulence, air-sea interactions, the generation and structure of surface, and internal ocean waves. After WW II, Eckart collected his work and the work of others on underwater detection and published it a classified volume entitled
Principles and Applications of Underwater Sound, which was first published in 1946. It was declassified in 1954 and reprinted in 1968. It is a standard reference. During the period 1957 to 1959, Eckart was a member of the Editorial Advisory Board for the
Johns Hopkins University Applied Physics Laboratory's series on applied mathematics and mechanics. From 1959 through 1970, he was also a consultant for commercial enterprises such as
General Dynamics Corporation and the
Rand Corporation. From 1965 to 1967, Eckart was vice-chancellor for academic affairs at UCSD. He then served the University of California, from 1967 to 1968, as alternate representative to the
Institute for Defense Analyses, which was made up of 12 member universities and functioned as an independent source for studies and advice for the
Department of Defense. Eckart contributed to the posthumous publication of some works by the mathematician
John von Neumann. ==Personal life==