Partition function (quantum field theory)

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Quantum field theory

Feynman diagram

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In quantum field theory, we have a generating functional, Z[J] of correlation functions and this value, called the partition function is usually expressed by something like the following functional integral:

where S is the action functional. This is very analogous to statistical mechanics. In fact, a Wick rotation emphasizes the similarities.

See also partition function (statistical mechanics)

[edit] Books

• Kleinert, Hagen, Path Integrals in Quantum Mechanics, Statistics, Polymer Physics, and Financial Markets, 4th edition, World Scientific (Singapore, 2004); Paperback ISBN 981-238-107-4 (also available online: PDF-files)