Physica Scripta
Aharonov–Anandan phases for spin–spin coupling in a rotating magnetic field
Mai-Lin Liang, Shun-Lin Shu, Bing Yuan
Abstract
Aharonov–Anandan (AA) phases for two coupled spins in a rotating magnetic field are obtained. The conditions for the adiabatic limit are also derived. It is found that if the rotating field is confined to a plane and the total spin is an integer, the adiabatic phase or the Berry phase will be zero, but the AA phase will not. Unlike adiabatic evolution, the AA phase is not the sum of geometric phases for the subsystems.