Regensburg 2022 – wissenschaftliches Programm

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QI: Fachverband Quanteninformation

QI 8: Quantum Sensors and Metrology

QI 8.9: Vortrag

Mittwoch, 7. September 2022, 17:30–17:45, H9

Ultra-low perturbation quantum measurements via random-time sampling — •Markus Sifft and Daniel Hägele — Ruhr University Bochum, Faculty of Physics and Astronomy, Experimental Physics VI (AG), Germany

Random-time sampling of a quantum system is introduced as a new approach to continuous quantum measurements with prospects for ultra-low-perturbation measurements [1]. Random sampling is, e.g., naturally realized in an optical spin noise experiment when weak probe-laser light exhibits random single-photon events in the detector [2]. Our theory shows that a direct evaluation of these detector click events yields power spectra that are equivalent but not identical to those of the usual Gaussian continuous measurement regime [3]. Surprisingly, this holds true even for average sampling rates much lower than the typical frequency range of the measured quantum dynamics. The third-order quantum polyspectrum (bispectrum) also contains the same information as its continuous counterpart. System characterization can, therefore, be performed using the analytic form of the quantum polyspectra [4]. Many applications of random- time sampling are envisioned for high-resolution spectroscopy, circuit quantum electrodynamics, quantum sensing, and quantum measurements in general. [1] https://arxiv.org/abs/2109.05862, [2] G. M. Müller et al., Physica E 43, 569 (2010), [3] M. Sifft et al., Phys. Rev. Res. 3, 033123 (2021) [4] D. Hägele et al., Phys. Rev. B 98, 205143 (2018)