Princeton University, Institute for Advanced Study (1947-1950); plasma and quantum theory research with Eugene Gross and David Pines; quantum theory book included theories of Niels Bohr, Wolfgang Pauli, Werner Heisenberg, Eugene Wigner, Erwin Schroedinger; subpoenaed by the Un-American Activities Committee (circa 1948-1949); obtained professor position at the University of Sao Paolo, Brazil, 1951; philosophy and politics, socialism, problems with science and society (circa 1950).
