title: Fidelity for kicked atoms with gravity near a quantum resonance.
abstract: Kicked atoms under a constant Stark or gravity field are investigated for experimental setups with cold and ultracold atoms. The parametric stability of the quantum dynamics is studied using the fidelity. In the case of a quantum resonance, it is shown that the behavior of the fidelity depends on arithmetic properties of the gravity parameter. Close to a quantum resonance, the long-time asymptotics of the fidelity is studied by means of a pseudoclassical approximation introduced by Fishman et al. [J. Stat. Phys. 110, 911 (2003)]. The long-time decay of fidelity arises from the tunneling out of pseudoclassical stable islands, and a simple ansatz is proposed which satisfactorily reproduces the main features observed in numerical simulations.
authors.affiliation: School of Mathematics, University of Bristol, University Walk, Clifton, Bristol BS8 1TW, United Kingdom.
authors.forename: Rémy
authors.initials: R
authors.lastname: Dubertrand
authors.forename: Italo
authors.initials: I
authors.lastname: Guarneri
authors.forename: Sandro
authors.initials: S
authors.lastname: Wimberger