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Q: Fachverband Quantenoptik und Photonik

Q 57: Poster 3: Quantengase, Ultrakalte Atome, Ultrakalte Moleküle, Materiewellen Optik, Präzisionsmessungen, Metrologie

Q 57.38: Poster

Donnerstag, 17. März 2011, 16:30–19:30, P1

Detection of the Amplitude Mode in a Strongly Interacting Superfluid by Bragg Spectroscopy — •Sören Götze, Jannes Heinze, Jasper Simon Krauser, Bastian Hundt, Nick Fläschner, Christoph Becker, and Klaus Sengstock — Institut für Laser-Physik, Universität Hamburg

By the creation of ultracold quantum gases in optical lattices, superfluidity can be studied over a wide range of tunable parameters, including the regime of strong correlations. However, for an in-depth understanding of the system's excitational structure, especially in the strongly correlated regime, new methods of detection and analysis are required [1]. We report on the first dedicated investigation of the recently proposed amplitude mode using Bragg spectroscopy on a strongly interacting BEC in a 3D optical lattice. We compare our data with a spatially resolved, time-dependent dynamic Gutzwiller calculation and thereby clearly identify the underlying mode structure, including systematic shifts of the resonances, e.g. due to the backaction of the Bragg beams and beyond linear response effects [2].

[1] P. T. Ernst et al., Probing superfluids in optical lattices by momentum-resolved Bragg spectroscopy, Nature Physics advance online publication, 29.11.2009 (DOI: 10.1038/nphys1476)

[2] U. Bissbort et al., Detecting the Amplitude Mode of Strongly Interacting Lattice Bosons by Bragg Scattering, arXiv:1010.2205