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arXiv · 2111.09802

Coherent feedback cooling of a nanomechanical membrane with atomic spins

Gian-Luca Schmid·Chun Tat Ngai·Maryse Ernzer·Manel Bosch Aguilera·Thomas M. Karg·Philipp Treutlein
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Abstract

Coherent feedback stabilises a system towards a target state without the need of a measurement, thus avoiding the quantum backaction inherent to measurements. Here, we employ optical coherent feedback to remotely cool a nanomechanical membrane using atomic spins as a controller. Direct manipulation of the atoms allows us to tune from strong-coupling to an overdamped regime. Making use of the full coherent control offered by our system, we perform spin-membrane state swaps combined with stroboscopic spin pumping to cool the membrane in a room-temperature environment to ${T}={216}\,\mathrm{mK}$ ($\bar{n}_{m} = 2.3\times 10^3$ phonons) in ${200}\,\mathrm{{\mu}s}$. We furthermore observe and study the effects of delayed feedback on the cooling performance. Starting from a cryogenically pre-cooled membrane, this method would enable cooling of the mechanical oscillator close to its quantum mechanical ground state and the preparation of nonclassical states.

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Gian-Luca Schmid, Chun Tat Ngai, Maryse Ernzer, Manel Bosch Aguilera, Thomas M. Karg, Philipp Treutlein. 2021-11-18. Coherent feedback cooling of a nanomechanical membrane with atomic spins. https://doi.org/10.1103/physrevx.12.011020

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