Heidelberg 2015 – scientific programme

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A: Fachverband Atomphysik

A 18: Poster: Ultra-cold atoms, ions and BEC (with Q)

A 18.33: Poster

Tuesday, March 24, 2015, 17:00–19:00, C/Foyer

Single shot realization and characterization of multiple quantum phase transitions — •Robert Heck, Romain Müller, Aske R. Thorsen, Mario Napolitano, Mark G. Bason, Jan Arlt, and Jacob F. Sherson — Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark

Local manipulation of ultracold atomic clouds with optically induced micropotentials has in recent years become a versatile tool. Among others, they have been used for efficient BEC creation using the so-called dimple approach [1, 2], to form arbitrarily shaped traps [3], and recently to address single atoms in an optical lattice [4].

We present our setup for creating time-averaged potentials with a strongly focused laser beam. In analogy with previous work [2], we have demonstrated up to 30 consecutive, conservative crossings of the phase transition to a BEC. Here, however, we combine the approach with high-resolved QND imaging to enable the continuous characterization of the dynamics. This allows us to investigate online the evolution of the in-situ cloud across the transition. Next steps will be the single-shot detection of entire phase diagrams and investigations of the stochastic nature of condensation dynamics during the formation of a BEC.

Finally, our setup allows for the simultaneous loading of several micro traps. The coherence properties of these has been verified by the observation of interference in ballistic expansion.

[1] P. Pinkse et al., PRL 78, 990 (1997); [2] D. Stamper-Kurn et al., PRL 81, 2194 (1998); [3] K. Henderson et al., NJP 11, 043030 (2009); [4] C. Weitenberg et al., Nature 471, 319 (2011)