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A: Fachverband Atomphysik

A 2: Atomic Systems in External Fields I

A 2.1: Vortrag

Montag, 8. März 2010, 14:00–14:15, F 107

Pseudo-classical Theory for Fidelity of Kicked Ultracold Atoms — •Benedikt Probst¹, Italo Guarneri², and Sandro Wimberger¹ — ¹Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 19, D-69120 Heidelberg — ²Centre for Nonlinear and Complex Systems, Universitá degli Studi dell’Insubria, Via Valleggio 11, I-22100 Como

Fidelity, the overlap of two wave functions evolved with slightly different Hamiltonians, constitutes a sensitive measure to probe the dynamical evolution of a quantum system. We investigate the energy absorption of (ultra)cold atoms periodically kicked by an optical lattice, which is a realization of the famous quantum kicked rotor. We study this model in a regime with classical completely chaotic dynamics. In the vicinity of resonant kicking, the problem maps, however, to a pseudo-classical system, which allows us to apply semi-classical methods. In this case we can use semi-classics on a nearly integrable phase space to describe the quantum behaviour. Based on this pseudo-classical model, we analytically predict the occurrence of revivals for the fidelity. These revivals can be understood as recurrences in the pseudo-classical phase space. Our predictions are supported by numerical simulations. Moreover, a possible experimental verification is discussed.