1Department of Physics, Shandong Normal University, Jinan 250014
2Department of Modern Physics, University of Science and Technology of China, Hefei 230027
3Department of Physics, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260
Geometric Phase for Mixed States
TONG Dian-Min1,3;CHEN Jing-Ling3;DU Jiang-Feng2
1Department of Physics, Shandong Normal University, Jinan 250014
2Department of Modern Physics, University of Science and Technology of China, Hefei 230027
3Department of Physics, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260
Abstract： The geometric phase of mixed states with non-degenerate eigenvalues is investigated. A general formula of geometric phase for mixed state under unitary evolution is given. In particular, we also furnish an expression of Hamiltonians for equivalent evolutions, by which one can understand what kind of evolutional operator U(t) (or Hamiltonian) is related to zero instantaneous dynamic phase. Moreover, the geometric phase and related Hamiltonians in the spin-half case are provided as an explicit example.
2003, Vol. 20 
