Hamburg 2009 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 1: Mikromechanische Oszillatoren

Q 1.5: Vortrag

Montag, 2. März 2009, 11:45–12:00, ESA-A

Cavity optomechanics with a Bose-Einstein condensate — •Christine Guerlin, Ferdinand Brennecke, Stephan Ritter, Kristian Baumann, Tobias Donner, and Tilman Esslinger — Institute for Quantum Electronics, ETH Zürich, CH-8093, Switzerland

In our experiment we study the coupling between a Bose-Einstein condensate and an ultrahigh-finesse optical cavity. The tremendous degree of control over atomic gases achieved in Bose-Einstein condensates combined with the rich field of cavity quantum electrodynamics opens access to a wealth of new physics, ranging from studies of the coupling between quantized light and coherent matter to the implementation of tools for quantum communication.

In the dispersive regime, our system realizes a model of cavity optomechanics. This research field typically studies the coupling of the mechanical degree of freedom of one of the cavity mirrors to the light field via radiation pressure. In our case, the mechanical oscillation is given by a coherent and periodic density modulation of the atomic cloud driven by dipole forces due to the cavity light field. We have observed this density modulation and very strong optical nonlinearities, present even at the single photon level. Furthermore our micro-mechanical oscillator naturally starts in its ground state, from which a single motional excitation can cause a shift of the cavity resonance on the order of the cavity linewidth. Our system is therefore promising to study the quantum regime of cavity optomechanics. We hope to reveal signatures of the quantum nature of the light and matter fields in further experiments.