Explaining the Geometric Phase and Adiabatic Evolution of a Quantum System

Jie Liu, Sheng-Chang Li, Libin Fu +1 more

Arno Böhm, Ali Mostafazadeh, Hiroyasu Koizumi +2 more

Atushi Tanaka, Taksu Cheon

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.

Arno Böhm

Mohammad Mehrafarin, Reza Torabi

Geometric phase in the wave function is important with regard to quantum non-locality and adiabatic evolution. We study the confinement of a particle by three-dimensional isotropically moving walls, of relevance to experimental trapping techniques, via a proposed approach that explains the physical origin of the geometric Dirac phase induced in the wave function. This phase depends only on the relative rate of change of the spatial scale factor. The approach also yields the class of external potentials that replicate adiabatic evolution in finite time. As illustrative examples, we consider uniform and accelerating walls, and the case where the Dirac phase is due to cosmic expansion.

Andrzej Herdegen