Kinematic approach to the mixed state geometric phase in nonunitary evolution

Abstract

A kinematic approach to the mixed state geometric phase in nonunitary evolution was proposed. The proposed geometric phase was shown to be gauge invariant, depending only upon the path the state space of the considered system. It was demonstrated that the proposed phase for nonunitarily evolving mixed states was testable experimentally in interferometry. The phase was also shown to lead to the previously obtained results when the evolution is unitary.