Werner Karl Heisenberg ( December 5 , 1901 - February 1 , 1976 ) was a German physicist , Nobel Prize winner and one of the people who started a new area of physics called quantum mechanics . Werner Heisenberg ( 5 December 1901 â `` 1 February 1976 ) was a German theoretical physicist who made foundational contributions to quantum mechanics and is best known for asserting the uncertainty principle of quantum theory .