Revivals of coherence in chaotic atom-optics billiards (8 pages)

Tzahi Grünzweig

Mitsuyoshi Tomiya, Hiroyoshi Tsuyuki, Shoichi Sakamoto

S. Sridhar, Daniel O. Hogenboom, Balam A. Willemsen

O. F. de Alcantara Bonfim, J. Florencio, F. C. Sá Barreto

Mikkel F. Andersen, Tzahi Grünzweig, Ariel Kaplan +1 more

We investigate the coherence properties of thermal atoms confined in optical dipole traps where the underlying classical dynamics is chaotic. A perturbative expression derived for the coherence of the echo scheme of Anderson et al. [Phys. Rev. Lett. 90, 023001 (2003)] shows that it is a function of the survival probability or fidelity of eigenstates of the motion of the atoms in the trap. The echo coherence and the survival probability display ``system specific'' features, even when the underlying classical dynamics is chaotic. In particular, partial revivals in the echo signal and the survival probability are found for a small shift of the potential. Next, a ``semiclassical'' expression for the averaged echo signal is presented and used to calculate the echo signal for atoms in a light sheet wedge billiard. Revivals in the echo coherence are found in this system, indicating that they may be a generic feature of dipole traps.

Mikkel F. Andersen, Ariel Kaplan, Tzahi Grünzweig +1 more

We perform echo spectroscopy on ultracold atoms in atom-optics billiards to study their quantum dynamics. The detuning of the trapping laser is used to change the "perturbation", which causes a decay in the echo coherence. Two different regimes are observed: first, a perturbative regime in which the decay of echo coherence is nonmonotonic and partial revivals of coherence are observed in contrast with the predictions of random matrix theory. These revivals are more pronounced in traps with mixed dynamics as compared to traps where the dynamics is fully chaotic. Next, for stronger perturbations, the decay becomes monotonic and independent of the strength of the perturbation. In this regime no clear distinction can be made between chaotic traps and traps with mixed dynamics.