Heidelberg 2015 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 70: Ultracold Atoms, Ions and BEC V (with A)
Q 70.2: Talk
Friday, March 27, 2015, 11:15–11:30, M/HS1
Cavity-Optomechanics with cold atoms: Quantum mechanical oscillators coupled by a cavity-mediated optical spring — •Nicolas Spethmann1,2, Jonathan Kohler1, Sydney Schreppler1, Lukas Buchmann1, and Dan Stamper-Kurn1 — 1University of California, Berkeley — 2Universität Kaiserslautern
A complex quantum system can be constructed by coupling simple quantum elements to one another. Oscillators comprised of the collective motion of ultracold, neutral atoms are excellent model systems in the quantum regime. However, neutral atoms inherently exhibit only weak interactions, so that it is a challenge to create tuneable, long-range coupling. Such interactions can be induced employing photons in a cavity containing the ultracold atoms. Because of the decay of cavity photons, such a coupling necessarily leads to measurement back-action noise being imparted onto the oscillators.
We demonstrate cavity-mediated coupling between two near-groundstate oscillators composed of ultracold Rb atoms trapped inside a high-finesse cavity. We observe phase-coherent transfer of excitation between the oscillators. At the same time, we detect the motional noise of the oscillators to monotonically increase with coupling time due to back-action. We show that this back-action noise exhibits two-oscillator correlations, reflecting the properties of the coupled mode system during cavity-mediated interaction. Our results point to the potential, and also the challenge, of coupling quantum oscillators with light.