NANOSYSTEMS: PHYSICS, CHEMISTRY, MATHEMATICS, 2015, 6 (6), P. 786-792
A topological formulation for exotic quantum holonomy
A. Tanaka – Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan; email@example.com
T.Cheon – Laboratory of Physics, Kochi University of Technology, Tosa Yamada, Kochi 782-8502, Japan
An adiabatic change of parameters along a closed path may interchange the (quasi-)eigenenergies and eigenspaces of a closed quantum system. Such discrepancies, induced by adiabatic cycles are referred to as the exotic quantum holonomy, which is an extension of the geometric phase. \Small” adiabatic cycles induce no change on eigenspaces, whereas some \large” adiabatic cycles interchange eigenspaces. We explain the topological formulation for the eigenspace anholonomy, where the homotopy equivalence precisely distinguishes the larger cycles from smaller ones. An application to two level systems is explained. We also examine the cycles that involve the adiabatic evolution across an exact crossing, and the diabatic evolution across an avoided crossing. The latter is a nonadiabatic example of the exotic quantum holonomy.
Keywords: exotic quantum holonomy, homotopy, disclination.