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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Optimal Quantum Thermometry with Coarse-Grained Measurements

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Author(s):
Hovhannisyan, V, Karen ; Jorgensen, Mathias R. [1] ; Landi, Gabriel T. [2] ; Alhambra, Alvaro M. [3] ; Brask, Jonatan B. [1] ; Perarnau-Llobet, Marti [4]
Total Authors: 6
Affiliation:
[1] Tech Univ Denmark, Dept Phys, DK-2800 Lyngby - Denmark
[2] Univ Sao Paulo, Inst Fis, BR-05314970 Sao Paulo - Brazil
[3] Max Planck Inst Quantum Opt, D-85748 Garching - Germany
[4] Univ Geneva, Dept Phys Appl, CH-1211 Geneva - Switzerland
Total Affiliations: 4
Document type: Journal article
Source: PRX QUANTUM; v. 2, n. 2 MAY 19 2021.
Web of Science Citations: 0
Abstract

Precise thermometry for quantum systems is important to the development of new technology, and understanding the ultimate limits to precision presents a fundamental challenge. It is well known that optimal thermometry requires projective measurements of the total energy of the sample. However, this is infeasible in even moderately sized systems, where realistic energy measurements will necessarily involve some coarse-graining. Here we explore the precision limits for temperature estimation when only coarse-grained measurements are available. Using tools from signal processing, we derive the structure of optimal coarse-grained measurements and find that good temperature estimates can generally be attained even with a small number of outcomes. We apply our results to many-body systems and nonequilibrium thermometry. For the former, we focus on interacting spin lattices, both at and away from criticality, and find that the Fisher-information scaling with system size is unchanged after coarse-graining. For the latter, we consider a probe of given dimension interacting with the sample, followed by a measurement of the probe. We derive an upper bound on arbitrary, nonequilibrium strategies for such probe-based thermometry and illustrate it for thermometry on a Bose-Einstein condensate using an atomic quantum-dot probe. (AU)

FAPESP's process: 17/50304-7 - Entropy production in non-equilibrium quantum processes: from foundations to quantum technologies
Grantee:Gabriel Teixeira Landi
Support Opportunities: Regular Research Grants
FAPESP's process: 17/07973-5 - Thermodynamics and information technologies with continuous variable quantum systems
Grantee:Gabriel Teixeira Landi
Support Opportunities: Regular Research Grants