Jean Ringot | Searcharxiv

arXiv2002

Observation of sub-Fourier resonances in a quantum-chaotic system

We experimentally show that the response of a quantum-chaotic system can display resonance lines sharper than the inverse of the excitation duration. This allows us to discriminate two neighboring frequencies with a resolution nearly 40 times better than the limit set by the Fourier inequality. Furthermore, numerical studies indicate that there is no limit, but the loss of signal, to this resolution, opening ways for the development of sub-Fourier quantum-chaotic signal processing.

quant-ph↗

arXiv2000

Experimental evidence of dynamical localization and delocalization in a quasi-periodic driven system

This paper presents the first experimental evidence of the transition from dynamical localization to delocalization under the influence of a quasi-periodic driving on a quantum system. A quantum kicked rotator is realized by placing cold atoms in a pulsed, far-detuned, standing wave. If the standing wave is periodically pulsed, one observes the suppression of the classical chaotic diffusion, i.e. dynamical localization. If the standing wave is pulsed quasi-periodically with two different frequencies, dynamical localization is observed or not, depending on the two frequencies being commensurable or incommensurable. One can thus study the transition from the localized to the delocalized case as a function of the effective dimensionality of the system.

physics.atom-ph↗