https://doi.org/10.1140/epjp/s13360-022-03524-7
Regular Article
Quantum thermometry with a dissipative quantum Rabi system
1
School of Science, Guilin University of Aerospace Technology, 541004, Guilin, Guangxi, People’s Republic of China
2
Department of Modern Physics, University of Science and Technology of China, 230026, Hefei, Anhui, People’s Republic of China
Received:
22
January
2022
Accepted:
22
November
2022
Published online:
8
December
2022
Dissipative quantum Rabi system, a finite-component system composed of a single two-level atom interacting with an optical cavity field mode, exhibits a quantum phase transition, which can be exploited to greatly enhance the estimation precision of unitary parameters (frequency and coupling strength). Here, using the quantum Langevin equation, standard mean field theory and adiabatic elimination, we investigate the quantum thermometry of a thermal bath surrounding the atom with quantum optical probes. With the increase in coupling strength between the atom and the cavity field, two kinds of singularities can be observed. One type of singularity is the critical point (CP) of phase transition from the normal to superradiant phase. The other type of singularity is the exceptional point (EP) in the anti-parity-time (anti-
) symmetrical cavity field. In many previous jobs, the optimal measurement precision can appear around EPs. However, we show that the optimal measurement precision occurs at the CP, instead of the EP. And the direct photon detection represents an excellent proxy for the optimal measurement near the CP. In the case where the thermal bath to be tested is independent of the extra thermal bath interacting with the cavity field, the estimation precision of the temperature always increases with the coupling strength. Oppositely, if the thermal bath to be tested is in equilibrium with the extra thermal bath interacting with the cavity field, noises that suppress the information of the temperature will be introduced when increasing the coupling strength unless it is close to the CP.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2022. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
