Combined feedback and sympathetic cooling of a mechanical oscillator coupled to ultracold atomsNew Journal of Physics, 20, 9 (2018)

19 September 2018

Photo: UHH/Rohse

Combined feedback and sympathetic cooling of a mechanical oscillator

A promising route to novel quantum technologies are hybrid quantum systems, which combine the advantages of several individual quantum systems. We have realized a hybrid atomic-mechanical experiment consisting of a Si₃N₄ membrane oscillator cryogenically precooled to 500 mK and optically coupled to a cloud of laser cooled ⁸⁷Rb atoms. Here, we demonstrate active feedback cooling of the oscillator to a minimum mode occupation of n=16 ± 1 corresponding to a mode temperature of T_min ≈ 200 μK. Furthermore, we characterize in detail the coupling of the membrane to the atoms by means of sympathetic cooling. By simultaneously applying both cooling methods we demonstrate the possibility of preparing the oscillator near the motional ground state while it is coupled to the atoms. Realistic modifications of our setup will enable the creation of a ground state hybrid quantum system, which opens the door for coherent quantum state transfer, teleportation and entanglement as well as quantum enhanced sensing applications.

Combined feedback and sympethetic cooling article link