General setting for a geometric phase of mixed states under an arbitrary nonunitary evolution
- Institute for Scientific Interchange (ISI), Villa Gualino, Viale Settimio Severo 65, I-10133 Turin (Italy)
The problem of a geometric phase for an open quantum system is reinvestigated in a unifying approach. Two of the existing methods to define geometric phase, one by Uhlmann's approach and the other by a kinematic approach, which have been considered to be distinct, are shown to be related in this framework. The method is based upon purification of a density matrix by its uniform decomposition and a generalization of the parallel transport condition obtained from this decomposition. It is shown that the generalized parallel transport condition can be satisfied when Uhlmann's condition holds. However, it does not mean that all solutions of the generalized parallel transport condition are compatible with those of Uhlmann's. It is also shown how to recover the earlier known definitions of geometric phase as well as how to generalize them when degeneracy exists and varies in time.
- OSTI ID:
- 20786639
- Journal Information:
- Physical Review. A, Vol. 73, Issue 1; Other Information: DOI: 10.1103/PhysRevA.73.012107; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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