Nonequilibrium and local detection of the normal fraction of a trapped two-dimensional Bose gas

Year: 2011

Authors: Carusotto I., Castin Y.

Autors Affiliation: INO-CNR BEC Center and Dipartimento di Fisica, Università di Trento, I-38123 Povo, Italy; Laboratoire Kastler Brossel, Ecole normale superieure, UPMC and CNRS, 24 rue Lhomond, F-75231 Paris Cedex 05, France

Abstract: We propose a method to measure the normal fraction of a two-dimensional Bose gas, a quantity that generally differs from the noncondensed fraction. The idea is based on applying a spatially oscillating artificial gauge field to the atoms. The response of the atoms to the gauge field can be read out either mechanically from the deposited energy into the cloud or optically from the macroscopic optical properties of the atomic gas. The local nature of the proposed scheme allows one to reconstruct the spatial profile of the superfluid component; furthermore, the proposed method does not require having established thermal equilibrium in the gas in the presence of the gauge field. The theoretical description of the system is based on a generalization of the Dum-Olshanii theory of artificial gauge fields to the interacting many-body context. The efficiency of the proposed measurement scheme is assessed by means of classical field numerical simulations. An explicit atomic level scheme minimizing disturbing effects such as spontaneous emission and light shifts is proposed for Rb-87 atoms.

Journal/Review: PHYSICAL REVIEW A

Volume: 84 (5)      Pages from: 53637-1  to: 53637-24

More Information: We acknowledge useful discussions with G. La Rocca, S. Stringari, F. Gerbier, C. Salomon, and J. Dalibard. The work of Y.C. was done as part of the ERC Project FERLODIM N.228177. Y.C. is a member of IFRAF and acknowledges financial support from IFRAF. I.C. acknowledges financial support from ERC through the QGBE grant.
KeyWords: Einstein Condensate; Feshbach Resonances; Fermi Gas; Quantum; Symmetry; Phase; Noise; Light
DOI: 10.1103/PhysRevA.84.053637

Citations: 5
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