Wigner's theorem on symmetries in indefinite metric spaces

• DOI: 10.1007/bf01608993
• Publication Date: 2005-04-30T03:39:28Z
• Authors: L. Bracci; G. Morchio; F. Strocchi
• Keywords: 81.46; 0103 physical sciences; 01 natural sciences

The description of symmetries in indefinite metric spaces is investigated. It is shown that ray transformations preserving the modulus of an indefinite scalar product can be implemented by linear or antilinear vector transformations which are generalized unitary or antiunitary operators with respect to the indefinite scalar product. A numbero f interesting features arise since such operators need not to be bounded.