This project addresses theoretical considerations regarding a "geometrical" phase (Berry's phase) by which the state of a quantum system changes if a closed path is traced in the space of parameters of the Hamiltonians of the system. This has been an active area for the past two or three years. This project will attempt to investigate the relativity between Berry's phase and electromagnetic and gravitational phases and to study the case of interacting systems. This theoretical work could lead to further experimental tests. Since quantum interference effects from phase differ- ences have, in some cases, practical application, it is pos- sible that such application could eventually result from this work, but no immediate applications can be foreseen.
