In quantum field theory, a branch of physics, the CPT theorem states that any canonical (that is, local and Lorentz-covariant) quantum field theory is invariant under the CPT operation, which is a combination of three discrete transformations: charge conjugation C, parity transformation P, and time reversal T. It was first proved by G.Lüders, W.Pauli and J.Bell in the framework of Lagrangian field theory.
At present, CPT is the sole combination of C, P, T observed as an exact symmetry of nature at the fundamental level.
- G. Lüders, Math. Fysik. Medd. Kgl. Danske Akad. Ved. Volume 28, 1954, p. 5.
- W. Pauli, in W. Pauli, ed., Niels Bohr and the Development of Physics (McGraw-Hill, New York, 1955).
- J.S. Bell, Birmingham University thesis (1954).
- Alan Kostelecky, The Status of CPT, arXiv:hep-ph/9810365.