Bonn 2025 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 48: Poster – Quantum Optics, Technologies, and Optomechanics

Q 48.24: Poster

Mittwoch, 12. März 2025, 17:00–19:00, Tent

Feedback cooling of levitated nanoparticles based on single photon detection — •Luis Kunkel Garcia, Henning Rudolph, and Klaus Hornberger — University of Duisburg-Essen, Faculty of Physics, Lotharstraße 1, 47057 Duisburg, Germany

Recent experiments demonstrate groundstate cooling of optically levitated nanoparticles by combining efficient homodyne detection of the scattered light with feedback [1,2]. Here, we theoretically analyze a scheme to optimally cool smaller nanoparticles into the quantum regime, provided that only single photon detection events of the scattered light intensity are available. The measurement rate then depends only on the square of the particle coordinate. This requires a Bayesian analysis of the entire history of the photon counts, in combination with a stochastic choice of the feedback force. We estimate the attainable temperature under realistic assumptions concerning the detection efficiency and dark count rates.

[1] Magrini et al., Real-time optimal quantum control of mechanical motion at room temperature. Nature 595, 373 (2021)

[2] Tebbenjohanns et al., Quantum control of a nanoparticle optically levitated in cryogenic free space. Nature 595, 378 (2021)

Keywords: Levitated optomechanics; Feedback cooling; Nanoparticles