Carl Werner Heisenberg, German physicist, c 1920s.
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Carl Werner Heisenberg (1901-1976) was a major creative figure amongst those who revolutionised physics by quantum mechanics. In 1925 he formulated a non-relativistic form of the theory of quantum mechanics, producing the matrix mechanics version- an equivalent of Schrodinger's wave mechanics theory which was produced independently in the same year. In 1927 Heisenberg discovered the principle of uncertainty, which states that it is impossible to determine exactly both the position and momentum of a particle simultaneously. He received the Nobel Prize for Physics in 1932.