title: Off-diagonal geometric phases.
abstract: We investigate the adiabatic evolution of a set of nondegenerate eigenstates of a parametrized Hamiltonian. Their relative phase change can be related to geometric measurable quantities that extend the familiar concept of Berry phase to the evolution of more than one state. We present several physical systems where these concepts can be applied, including an experiment on microwave cavities for which off-diagonal phases can be determined from published data.
authors.affiliation: European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble Cedex, France. manini@sissa.it
authors.forename: N
authors.initials: N
authors.lastname: Manini
authors.forename: F
authors.initials: F
authors.lastname: Pistolesi