Stability of wave packet dynamics under perturbations
Abstract
We introduce a novel method to investigate the stability of wave packet dynamics under perturbations of the Hamiltonian. Our approach relies on semiclassical approximations, but is non-perturbative. Two separate contributions to the quantum fidelity are identified: one factor derives from the dispersion of the wave packets, whereas the other factor is determined by the separation of a trajectory of the perturbed classical system away from a corresponding unperturbed trajectory. We furthermore estimate both contributions in terms of classical Lyapunov exponents and find a decay of fidelity that is, generically, at least exponential, but may also be doubly exponential. The latter case is shown to be realised for inverted harmonic oscillators.
Cite
@article{arxiv.nlin/0509016,
title = {Stability of wave packet dynamics under perturbations},
author = {Jens Bolte and Tobias Schwaibold},
journal= {arXiv preprint arXiv:nlin/0509016},
year = {2009}
}