(1901–1976). A native of Germany, Heisenberg received his doctorate from the University of Munich in 1923, after which he was closely associated for several years with Niels Bohr in Copenhagen. He was awarded the Nobel Prize in physics in 1932 for his brilliant work in quantum mechanics. In 1946, he became director of the Max Planck Institute. His notable contributions to theoretical physics, best known of which was the uncertainty principle, imparted new impetus to nuclear physics and made possible a better understanding of atomic structure and chemical bonding.See Uncertainty Principle.