Werner Heisenberg (right, 1901-1976), German physicist. Heisenberg was awarded the 1932 Nobel Prize in Physics for his work on a matrix theory of quantum mechanics. It was a dualistic theory, meaning that phenomena could be described either in terms of waves or in terms of the new quanta (particles). In 1927, Heisenberg had stated his uncertainty principle that a particle's momentum and position cannot both be determined. This means that subatomic events depend on probabilities.