Nonadiabatic Berry Phase of a Two-State System and Nonstationarity of Quantum States11The project supported by National Natural Science Foundation of China, the Post-Doctoral Foundation of China

Abstract

The nonadiabatic Berry phases in the magnetic resonance under various initial conditions are investigated and compared with the adiabatic Berry phase. The general formalism for calculating the nonadiabatic Berry phase of a two-state system in terms of the expansion of instantaneous energy eigenstates is presented. Some numerical calculations and discussions are made. The Berry phase of a two-statesystem under an impulsive interaction is addressed.