David Finkelstein

David Ritz Finkelstein (July 19, 1929 – January 24, 2016) was an emeritus professor of physics at the Georgia Institute of Technology. Born in New York City, Finkelstein obtained his Ph.D. in physics at the Massachusetts Institute of Technology in 1953 and taught at Stevens Institute of Technology through 1960, while he also held a Ford Foundation Fellowship at the European Organization for Nuclear Research from 1959-1960. From 1964 to 1976, he was professor of physics at Yeshiva University. He became a member of the faculty at Georgia Tech in 1980.

In 1958, Finkelstein and Charles W. Misner found the gravitational kink, a topological defect in the gravitational metric, whose quantum theory could exhibit spin 1/2. The simplest kink exhibited an easily understood event horizon that led him to recognize the one in the Schwarzschild metric and eliminate its coordinate singularity. In essence, Finkelstein determined that whatever falls past the Schwarzschild radius into a black hole cannot escape it; the membrane is one-directional. This important work influenced the decisions of Roger Penrose and John Archibald Wheeler to accept the physical existence of event horizons and black holes.

Most of Finkelstein's work is directed toward a quantum theory of space-time structure. He early on accepted the conclusion of John von Neumann that anomalies of quantum mechanical measurement are anomalies of the logic of quantum mechanical systems. Therefore, he formed quantum analogues of set theory, the standard language for classical space-time structures, and proposed that space-time is a quantum set of space-time quanta dubbed "chronons", a form of quantum computer with spins for quantum bits, as a quantum version of the cellular automaton of von Neumann. His early quantum space-times proving unphysical, he later studied chronons with a regularized form of Bose–Einstein statistics due to Tchavdar D. Palev.

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