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Q: Fachverband Quantenoptik und Photonik
Q 47: Quantum Technologies – Sensing II
Q 47.2: Talk
Thursday, March 5, 2026, 11:15–11:30, P 5
The boundary time crystal as a light source for quantum enhanced sensing beyond the heisenberg limit — •Malik Jirasek1, Igor Lesanovsky1,2, and Albert Cabot3 — 1Universität Tübingen, Tübingen, Germany — 2University of Nottingham, Nottingham, United Kingdom — 3Universitat de les Illes Balears, Palma de Mallorca, Spain
Modern precision measurements, such as interferometry for detecting gravitational waves, rely on the estimation of optical phases encoded in light fields. We propose to exploit the collectively enhanced output field of a driven-dissipative many-body open quantum system as a light source in order to improve the precision of estimating optical phases [1]. These systems can generate emission patterns that are drastically different than those of conventional sources, for example lasers. For instance, the output fields of time crystals can exhibit intricate time-correlations. We find, that these benefit the sensitivity of measurement protocols for phase shifts, which we show theoretically by employing a boundary time crystal (BTC) as a light source. The fundamental bound on the precision of such estimation shows scaling with system size of the BTC that surpasses the Heisenberg limit. This scaling can be partially harnessed by a protocol, in which the phase shifted light field is guided into an auxiliary replica system, which serves as a detector that is sensitive to non-trivial temporal correlations of the light.
[1] M. Jirasek, et al., arXiv:2511.23416 (2025)
Keywords: Time crystals; Collective spin systems; Quantum fisher information; Optical phase estimation