Adiabatic perturbation theory for two-component systems with one heavy component
Quantum Physics
2024-06-21 v2 Other Condensed Matter
Abstract
Perturbation theory with respect to the kinetic energy of the heavy component of a two-component quantum system is introduced. An effective Hamiltonian that is accurate to second order in the inverse heavy mass is derived. It contains a new form of kinetic energy operator with a Hermitian mass tensor and a complex-valued vector potential. All of the potentials in the effective Hamiltonian can be expressed in terms of covariant derivatives and a resolvent operator. The most salient application of the theory is to systems of electrons and nuclei. The accuracy of the theory is verified numerically in a model diatomic molecule and analytically in a vibronic coupling model.
Cite
@article{arxiv.2310.09189,
title = {Adiabatic perturbation theory for two-component systems with one heavy component},
author = {Ryan Requist},
journal= {arXiv preprint arXiv:2310.09189},
year = {2024}
}