摘要

We consider quantum dynamics for which the strict adiabatic approximation fails but which do not escape too far from the adiabatic limit. To treat these systems we introduce a generalization of the time-dependent wave operator theory which is usually used to treat dynamics which do not escape too far from an initial subspace called the active space. Our generalization is based on a time-dependent adiabatic deformation of the active space. The geometric phases associated with the almost adiabatic representation are also derived. We use this formalism to study the adiabaticity of a dynamics surrounding an exceptional point of a non-Hermitian Hamiltonian. We show that the generalized time-dependent wave operator can be used to correct easily the adiabatic approximation which is very imperfect in this situation.

  • 出版日期2014-2-14