Werner Heisenberg - Quantum Pioneer and German Weapons Researcher

Quantum Mechanics and Uncertainty: A central figure in 20th Century Physics. Heisenberg was a founder of quantum mechanics: his formulation of matrix mechanics allowed detailed predictions to be made and lead ot his famous uncertainty principle.

Fast Facts and Dates:

• Born: 5 December, 1901 in Wurzburg (Germany).
• Died: 1 February, 1976 in Munich from cancer.
• 1918: Involved in the supression of the Bavarian Soviet Republic
• 1923, July: Receives his Doctorate (but only after a difficult oral exam) 1924: Moves to Copenhagen to Study under Bohr.
• 1927, March 3: Uncertianty Principle paper received.
• 1939, September 26: Joins the Berlin Nuclear Fission Project
• 1941, September 15-22: Visits occupied Copenhagen to discuss fission with Bohr.

Copenhagen and Quantum Mechanics: Working with Bohr, Heisenberg developes a theory known as Matrix Mechanics. Quantum states are represented by complex vectors and their evolution is repesented by acting on those vectors with matrices (known as operators).Uncertainty:

The more precisely the position is determined, the less precisely the momentum is known in this instant, and vice versa.

--Heisenberg, uncertainty paper, 1927

At Copenhagen, he also developed the Uncertainty Principle - proving that the product of the uncertainty in the position and momentum of a particle is always greater than Planck's Constant (h) divided by 4 π.

Nuclear Fission: Although never apparently a Nazi, Heisenberg led Hitler's Nuclear Fission project during world war two. He appears to have made a number of miscalculations during this project, including a vast overestimation of the critical mass required to make a bomb. Although there is a theory that this was a deliberate sabotage on his part to keep nuclear weapons out of Hitler's hands, it is generally believed that Heisenberg was wholeheartedly trying to help Germany win the war.
Occupied Copehagen: In September, 1941, Heisenberg visited the home of his old Mentor Neils Bohr in Occupied Copenhagen. Both men recalled very different versions of this meeting after the war. Bohr claimed that Heisenberg was after his assistance with the nuclear weapons project but Heisenberg claimed that he came to tell Bohr that he was trying to hinder the research. This mysterious meeting was the basis of the hugely successful play Copenhagen by Michael Frayn.
After the War: Heisenberg spent a short period interred at Farm Hall in England with other German physicists before returning to Germany. There he headed the German Research Council and attempted a serious overhaul of the West German scientific research, eventually helping set up the very succesful West German Nuclear Weapons industry.