title: Quantum enhancement of momentum diffusion in the delta-kicked rotor.
abstract: We present detailed observations of the quantum delta-kicked rotor in the vicinity of a quantum resonance. Our experiment consists of an ensemble of cold cesium atoms subject to a pulsed off-resonant standing wave of light. We measure the mean energy and show clearly that at the quantum resonance it is a local maximum. We also examine the effect of noise on the system and find that the greatest sensitivity to this occurs at the resonances. This makes these regions ideal for examining quantum-classical correspondence. A picture based on diffraction is developed which allows the experiments to be readily understood.
authors.affiliation: Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom.
authors.forename: M B
authors.initials: MB
authors.lastname: d'Arcy
authors.forename: R M
authors.initials: RM
authors.lastname: Godun
authors.forename: M K
authors.initials: MK
authors.lastname: Oberthaler
authors.forename: D
authors.initials: D
authors.lastname: Cassettari
authors.forename: G S
authors.initials: GS
authors.lastname: Summy