Dresden 2011 – wissenschaftliches Programm
A 26.66: Poster
Donnerstag, 17. März 2011, 16:00–18:30, P2
Self-rephasing of a cold atomic ensemble for extended coherence times — •Christian Deutsch1, Fernando Ramirez-Martinez2, Wilfried Maineult2, Clement Lacroûte2, Friedemann Reinhard1, Jean-Noël Fuchs3, Fréderic Piéchon3, Franck Laloë1, Jakob Reichel1, and Peter Rosenbusch2 — 1LKB - Ecole Normale Supérieure - UPMC - CNRS - Paris — 2SYRTE - Observatoire de Paris - UPMC - CNRS - Paris — 3Laboratoire de Physique des Solides- Univ. Paris-Sud - CNRS - Orsay
We report on the observation of very long coherence times on ultracold trapped 87Rb atoms. The experiment is designed to operate a microwave atomic clock in the 10−13 s−1/2 stability regime in a compact setup. The spatial inhomogeneities of Zeeman and collisional shift are largely compensated. Remaining field inhomogeneities limit the frequency spread to < 80mHz giving rise to dephasing of the individual atoms on a timescale of 2 to 3 s . Surprisingly the coherence time is more than an order of magnitude larger than expected.
We explain this by a rephasing of the atomic spins driven by the Identical Spin Rotation Effect acting as a continous spin echo. The interaction effect is demonstrated by tuning the atom density and thereby the ISRE rate.
The effect is very general in nature and should be observable in a multitude of systems.
 IEEE TUFFC 56, 106 (2010),  Appl Phys B 95, 227 (2009),  Phys Rev. Lett. 102, 215301 (2009),  Phys Rev Let 105, 2, 020401 (2010)