Postdoc @ University of Geneva
Tuesday June 28 – 15.15 BST
Fundamental limits in Bayesian thermometry and attainability via adaptive strategies
We investigate the limits of quantum thermometry using quantum probes at thermal equilibrium within the Bayesian approach. We consider the possibility of engineering interactions between the probes in order to enhance their sensitivity, as well as feedback during the measurement process, i.e., adaptive protocols. On the one hand, we obtain an ultimate bound on thermometry precision in the Bayesian setting, valid for arbitrary interactions and measurement schemes, which lower bounds the error with a quadratic (Heisenberg-like) scaling with the number of probes. We develop an adaptive strategy that can saturate this limit. On the other hand, we derive a no-go theorem for non-adaptive protocols that does not allow for better than linear (shot-noise-like) scaling even if one has unlimited control over the probes, namely access to arbitrary many-body interactions. Our work highlights the crucial role of both feedback and many-body interactions in quantum thermometry. This talk is based on [1].
[1] Fundamental limits in Bayesian thermometry and attainability via adaptive strategies, Mohammad Mehboudi, Mathias R. Jørgensen, Stella Seah, Jonatan B. Brask, Jan Kołodyński, Martí Perarnau-Llobet, arXiv:2108.05932 (2021).