John von Neumann

:A separate article covers Saint John Neumann, the American priest.

Scientific contributions

Von Neumann was one of the initiators of game theory and published the classic book Theory of Games and Economic Behavior with Oskar Morgenstern in 1944. He worked in the Theory division at Los Alamos along with Hans Bethe and Victor Weisskopf during World War II as part of the Manhattan Project to develop the first atomic weapons.

Related Topics:
Game theory - Theory of Games and Economic Behavior - Oskar Morgenstern - 1944 - Los Alamos - Hans Bethe - Victor Weisskopf - World War II - Manhattan Project - Atomic weapon

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One of von Neumann's signature achievements was his rigorous mathematical formulation of quantum mechanics in terms of linear operators on Hilbert spaces. He provided a rigorous foundation for quantum statistical mechanics. He also proposed a proof of the impossibility of hidden variables, showing that quantum mechanics was profoundly different from all previously known theories in physics. His proof contained a conceptual flaw, although subsequently correct proofs were provided by John Bell and others. He apparently held a belief in the role of the observer in creating the collapse of the quantum wave function, which reflects in his contributions to the development of the theory of quantum measurement.

Related Topics:
Quantum mechanics - Linear operators - Hilbert spaces - Quantum statistical mechanics - Hidden variables - John Bell - Collapse of the quantum wave function - Quantum measurement

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Von Neumann gave his name to the von Neumann architecture used in most non-parallel-processing computers, because of his publication of the concept, though many feel that this naming ignores the contribution of J. Presper Eckert and John William Mauchly who worked on the concept during their work on ENIAC. Virtually every commercially available home computer, microcomputer and supercomputer is a von Neumann machine. He created the field of cellular automata without computers, constructing the first examples of self-replicating automata with pencil and graph paper. The concept of a universal constructor was fleshed out in his posthumous work Theory of Self Reproducing Automata. The term "von Neumann machine" also refers to self-replicating machines. Von Neumann proved that the most effective way large-scale mining operations such as mining an entire moon or asteroid belt can be accomplished is through the use of self-replicating machines, to take advantage of the exponential growth of such mechanisms.

Related Topics:
Von Neumann architecture - Computer - J. Presper Eckert - John William Mauchly - ENIAC - Microcomputer - Supercomputer - Von Neumann machine - Cellular automata - Self-replicating - Universal constructor - Moon - Asteroid belt - Exponential growth

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In addition to his work on architecture, he is credited with at least one contribution to the study of algorithms. Donald Knuth cites von Neumann as the inventor, in 1945, of the well known merge sort algorithm, in which the first and second halves of an array are each sorted recursively and then merged together.

Related Topics:
Donald Knuth - 1945 - Merge sort

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He also engaged in exploration of problems in the field of numerical hydrodynamics. With R. D. Richtmyer he developed an algorithm defining artificial viscosity, that proved essential to understanding many kinds of shock waves. It can fairly be said that we would not understand much of astrophysics, and might not even have highly developed jet and rocket engines, without that work. The problem to be solved was that when computers solve hydrodynamic or aerodynamic problems, they try to put too many computational gridpoints at regions of sharp discontinuity (shock waves). The artificial viscosity was a mathematical trick to slightly smooth the shock transition without sacrificing basic physics.

Related Topics:
Hydrodynamics - R. D. Richtmyer - Shock wave

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Von Neumann had a mind of great ingenuity and near total recall. He was an extrovert who loved drinking, dancing and having a good time. He had a fun-loving nature with a great love of jokes and humor. He died of cancer in Washington, D.C..

Related Topics:
Total recall - Washington, D.C.

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