BLOCH, FELIX

BLOCH, FELIX (1905–1983), U.S. physicist and Nobel Prize laureate. Bloch was born in Zurich. He studied first at the Federal Institute of Technology, where his interest in physics developed and he received his Ph.D. in theoretical physics under Heisenberg's supervision at the University of Leipzig (1928). He worked successively with leading contemporary physicists including Pauli, bohr , and Fermi before emigrating to the U.S. in 1933 after the Nazi rise to power. He joined Stanford University (1934), where he was Max Stein Professor of Physics from 1961. He served for one year (1954) as the first director general of CERN. Bloch's research interests started with his doctoral dissertation on the quantum mechanics of electrons in crystals. During World War II he worked on theoretical issues in the early stages of the Manhattan Project and on counteracting radar. He was awarded the Nobel Prize in physics (1952) jointly with E.M. Purcell for his discovery of nuclear induction. This process uses a magnetic field to align nuclear particles on the basis of their intrinsic angular moment (spin) and magnetic moment parallel to this spin. The resulting signals, analogous to radio-frequency spectroscopy, enabled him to measure the moment of the neutron with great accuracy. This discovery forms the basis of nuclear magnetic resonance scanning in medicine and related techniques for analyzing other solid structures. In his later years Bloch worked on the theory of superconductivity at low temperatures. (Michael Denman (2nd ed.)