title: Competition between Spin Echo and Spin Self-Rephasing in a Trapped Atom Interferometer.
abstract: We perform Ramsey interferometry on an ultracold ^{87}Rb ensemble confined in an optical dipole trap. We use a π pulse set at the middle of the interferometer to restore the coherence of the spin ensemble by canceling out phase inhomogeneities and creating a spin echo in the contrast. However, for high atomic densities, we observe the opposite behavior: the π pulse accelerates the dephasing of the spin ensemble leading to a faster contrast decay of the interferometer. We understand this phenomenon as a competition between the spin-echo technique and an exchange-interaction driven spin self-rephasing mechanism based on the identical spin rotation effect. Our experimental data are well reproduced by a numerical model.
authors: SYRTE, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Université Paris 06, LNE, 61 Avenue de l'Observatoire, 75014 Paris, France.
authors: C
authors: C
authors: Solaro
authors: SYRTE, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Université Paris 06, LNE, 61 Avenue de l'Observatoire, 75014 Paris, France.
authors: A
authors: A
authors: Bonnin
authors: Laboratoire de Physique des Solides, CNRS UMR 8502, Université Paris-Sud, Université Paris-Saclay, F-91405 Orsay Cedex, France.
authors: F
authors: F
authors: Combes
authors: SYRTE, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Université Paris 06, LNE, 61 Avenue de l'Observatoire, 75014 Paris, France.
authors: M
authors: M
authors: Lopez
authors: SYRTE, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Université Paris 06, LNE, 61 Avenue de l'Observatoire, 75014 Paris, France.
authors: X
authors: X
authors: Alauze
authors: Laboratoire de Physique des Solides, CNRS UMR 8502, Université Paris-Sud, Université Paris-Saclay, F-91405 Orsay Cedex, France.|Laboratoire de Physique Théorique de la Matière Condensée, CNRS UMR 7600, Université Pierre et Marie Curie, 4 place Jussieu, 75252 Paris Cedex 05, France.
authors: J-N
authors: JN
authors: Fuchs
authors: Laboratoire de Physique des Solides, CNRS UMR 8502, Université Paris-Sud, Université Paris-Saclay, F-91405 Orsay Cedex, France.
authors: F
authors: F
authors: Piéchon
authors: SYRTE, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Université Paris 06, LNE, 61 Avenue de l'Observatoire, 75014 Paris, France.
authors: F
authors: F
authors: Pereira Dos Santos