Quantum thermometry in a squeezed thermal bath

Abstract

We address the dephasing dynamics of the quantum Fisher information (QFI) for the process of quantum thermometry with probes coupled to squeezed thermal baths via the nondemolition interaction. We also calculate the upper bound for the parameter estimation and investigate how the optimal estimation is affected by the initial conditions and decoherence, particularly the squeezing parameters. Moreover, the feasibility of the optimal measurement of the temperature is discussed in detail. Then, the results are generalized for entangled probes and the multi-qubit scenarios for probing the temperature are analysed. Our results show that the squeezing can decrease the number of channel uses for optimal thermometry. Comparing different schemes for multi-qubit estimation, we find that an increase in the number of the qubits, interacting with the channel, does not necessarily vary the precision of estimating the temperature. Besides, we discuss the enhancement of the quantum thermometry using the parallel strategy and starting from the W state.

Collisional Quantum Thermometry

“…One such type, which stands out due to its universal importance, is thermometry [7,8]. Several papers have discussed how quantum resources could be used to yield significant enhancements in temperature estimation [9][10][11][12][13][14][15][16][17]. This could have a large impact particularly on low temperature applications such as ultra-cold atoms, trapped ions and superconducting devices, where minimally-invasive thermometric methods are seldom available (c.f.…”