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Q: Fachverband Quantenoptik und Photonik

Q 12: Quantum Optomechanics I

Q 12.6: Vortrag

Montag, 10. März 2025, 18:15–18:30, HS I

Towards Matter-Wave Interference Experiments with Levitated Nanoparticles — •Florian Fechtel, Stephan Troyer, Lorenz Hummer, Uroš Delić, and Markus Arndt — University of Vienna, VDS, VCQ, Faculty of Physics, Boltzmanngasse 5, A-1090 Vienna, Austria

When investigating microscopic systems, we usually successfully use quantum mechanics. However, understanding its transition to classical phenomena has remained a significant challenge. Levitated nanoparticles offer a promising platform for observing quantum behavior at mass scales beyond current limits. In our experiment, we trap 150 nm diameter silica nanoparticles, loaded into an infrared tweezer by laser-induced acoustic desorption. We employ coherent scattering cooling in ultra-high vacuum, with a high-finesse (F > 300,000) optical cavity driven by light scattered from the particle. By blue-detuning the cavity mode relative to the optical tweezer, we enhance Anti-Stokes scattering, effectively removing motional energy and cooling the three translational modes to temperatures below 10 mK. Using a fiber laser at 1550 nm, the ultimate cooling limit is constrained by laser phase noise, which acts as a stochastic heating force, as it converts to amplitude noise in the high-finesse cavity. To mitigate this effect, we implement a feedback loop that significantly reduces laser phase noise at frequencies relevant to particle motion. This allows for further cooling and enables precise temperature measurements using sideband thermometry. Looking ahead, we aim to conduct quantum experiments around translational and/or rotational interferometry.

Keywords: Levitodynamics; Laser-Induced Acoustic Desorption; Cavity Optomechanics; Coherent Scattering Cooling; Matter-Wave Interference