Quantum physics:


Werner Karl
Heisenberg
(1901 Würzburg - 1976 München)
 
The essential equality is the following:

pq - qp = h/(2πi)

(Heisenberg Uncertainty Principle)



p = position operator
q = momentum operator

Left side is just the commutator
    of two operators
Right side: a constant



For the mathematical foundation of quantum physics, one has to mention many more mathematics and physicists:
M. Planck, E. Schrödinger, P. Dirac, M. Born, N. Wiener, J. von Neumann, und vor allem auch: H. Weyl, ...