Werner Karl Heisenberg (5.12.1901 - 1.02.1976) was a German theoretical physicist and one of the creators of quantum mechanics. He was born in Würzburg. He graduated from the universities of Munich (1923) and Göttingen (1924). In 1927 — 41 he was professor of theoretical physics at the University of Leipzig, and in 1941 —45 director of the Kaiser Wilhelm Institute of Physics and professor at the University of Berlin. In 1946—58 he was director of the Institute of Physics and professor at the University of Göttingen. From 1958 he was director of the Institute of Physics and Astrophysics and professor at the University of Munich.
His work concerned quantum mechanics, quantum electrodynamics, relativistic quantum field theory, the theory of the nucleus, magnetism, the physics of cosmic rays, the theory of elementary particles and the philosophy of natural science. In 1925 he developed matrix mechanics, the first version of quantum mechanics (Nobel Prize, 1932). In 1926 he explained the difference between the two systems of terms for para- and orthohelium: the para terms correspond to the symmetric solutions of the wave equation and the ortho terms to the antisymmetric ones. In 1927 he formulated the uncertainty principle, which limits the application of classical concepts and ideas to microobjects.
Together with P. Dirac he put forward in 1928 the idea of exchange interaction, introducing exchange forces, and independently of Ya. I. Frenkel he developed the first quantum-mechanical theory of ferromagnetism, based on the exchange interaction of electrons (the model of localised spins). In 1929, together with W. Pauli, he attempted to give a formulation of quantum electrodynamics, introducing a general scheme for the quantisation of fields. He extended (1934—36) Dirac's theory of holes. Following him he postulated (1934) the existence of the effect of vacuum polarisation.
Following D. D. Ivanenko he arrived at the proton-neutron model of the nucleus (1932). In 1932 he introduced the concept of isotopic spin and showed that nuclear forces are saturating. He constructed a theory of nuclear forces, extending the Ivanenko — Tamm idea of exchange interaction. In 1943 he introduced the scattering matrix (the S-matrix) into quantum field theory, where it is an important tool for describing interaction. In his last years Heisenberg's efforts were directed at the creation of a unified field theory. In 1958 he quantised Ivanenko's nonlinear spinor equation (the Ivanenko — Heisenberg equation). A good many of his works were devoted to the philosophical problems of physics, in particular to the theory of knowledge, where he stands largely on the positions of idealism.
An honorary member of many academies of sciences and scientific societies. The C. Matteucci and M. Planck Medals and others.