The CPT Theorem

Frank Arntzenius

in The Oxford Handbook of Philosophy of Time

Published in print April 2011 | ISBN: 9780199298204
Published online September 2011 | e-ISBN: 9780191728372 | DOI:

Series: Oxford Handbooks in Philosophy

The CPT Theorem

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The CPT theorem says that any Lorentz invariant quantum field theory must also be invariant under the combined operation of charge conjugation C, parity P, and time reversal T, even though none of those individual invariances need hold. It is quite strange. Why should a quantum field theory be invariant under the combination of two spatiotemporal discrete transformations, and then a quite different type of transformation (matter–anti-matter transformation)? In one of the first attacks on these and related questions by a philosopher, this chapter argues that CPT symmetry is better understood as PT symmetry. If the author is right, CPT symmetry is really saying that quantum field theory does not care about temporal orientation or spatial handedness.

Keywords: quantum field theory; Lorentz; charge conjugation; parity; time reversal; CPT symmetry; temporal orientation

Article.  7639 words. 

Subjects: Philosophy of Science ; Metaphysics

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