Geometric phase via adiabatic manipulations of the environment

It has been shown that geometric phases may be generated in a quantum system subject to noise by adiabatic manipulations of the fluctuating fields, e.g., by variation of the system-environment coupling. For a two-state quantum system, this phase is expressed in terms of the geometry of the path, traversed by the slowly varying direction and amplitude of the fluctuations. The origin of this phase and the possibilities of separating it from the known environment-induced modification of the Berry phase are discussed. The text was submitted by the authors in English.