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Tight bound on finite-resolution quantum thermometry at low temperatures

Jørgensen, Mathias R. ; Potts, Patrick P. LU orcid ; Paris, Matteo G. A. and Brask, Jonatan B. (2020) In Physical Review Research 2(3).
Abstract
Precise thermometry is of wide importance in science and technology in general and in quantum systems in particular. Here, we investigate fundamental precision limits for thermometry on cold quantum systems, taking into account constraints due to finite measurement resolution. We derive a tight bound on the optimal precision scaling with temperature, as the temperature approaches zero. The bound demonstrates that under finite resolution, the variance in any temperature estimate must decrease slower than linearly. This scaling can be saturated by monitoring the nonequilibrium dynamics of a single-qubit probe. We support this finding by numerical simulations of a spin-boson model. In particular, this shows that thermometry with a vanishing... (More)
Precise thermometry is of wide importance in science and technology in general and in quantum systems in particular. Here, we investigate fundamental precision limits for thermometry on cold quantum systems, taking into account constraints due to finite measurement resolution. We derive a tight bound on the optimal precision scaling with temperature, as the temperature approaches zero. The bound demonstrates that under finite resolution, the variance in any temperature estimate must decrease slower than linearly. This scaling can be saturated by monitoring the nonequilibrium dynamics of a single-qubit probe. We support this finding by numerical simulations of a spin-boson model. In particular, this shows that thermometry with a vanishing absolute error at low temperature is possible with finite resolution, answering an interesting question left open by previous work. Our results are relevant both fundamentally, as they illuminate the ultimate limits to quantum thermometry, and practically, in guiding the development of sensitive thermometric techniques applicable at ultracold temperatures. (Less)
Please use this url to cite or link to this publication:
author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review Research
volume
2
issue
3
publisher
American Physical Society
external identifiers
  • scopus:85098281239
ISSN
2643-1564
DOI
10.1103/PhysRevResearch.2.033394
language
English
LU publication?
yes
id
3c0eb139-9e93-4fea-b9d0-246070b09bdb
alternative location
https://link.aps.org/doi/10.1103/PhysRevResearch.2.033394
date added to LUP
2020-11-18 10:23:29
date last changed
2023-11-08 02:56:30
@article{3c0eb139-9e93-4fea-b9d0-246070b09bdb,
  abstract     = {{Precise thermometry is of wide importance in science and technology in general and in quantum systems in particular. Here, we investigate fundamental precision limits for thermometry on cold quantum systems, taking into account constraints due to finite measurement resolution. We derive a tight bound on the optimal precision scaling with temperature, as the temperature approaches zero. The bound demonstrates that under finite resolution, the variance in any temperature estimate must decrease slower than linearly. This scaling can be saturated by monitoring the nonequilibrium dynamics of a single-qubit probe. We support this finding by numerical simulations of a spin-boson model. In particular, this shows that thermometry with a vanishing absolute error at low temperature is possible with finite resolution, answering an interesting question left open by previous work. Our results are relevant both fundamentally, as they illuminate the ultimate limits to quantum thermometry, and practically, in guiding the development of sensitive thermometric techniques applicable at ultracold temperatures.}},
  author       = {{Jørgensen, Mathias R. and Potts, Patrick P. and Paris, Matteo G. A. and Brask, Jonatan B.}},
  issn         = {{2643-1564}},
  language     = {{eng}},
  number       = {{3}},
  publisher    = {{American Physical Society}},
  series       = {{Physical Review Research}},
  title        = {{Tight bound on finite-resolution quantum thermometry at low temperatures}},
  url          = {{http://dx.doi.org/10.1103/PhysRevResearch.2.033394}},
  doi          = {{10.1103/PhysRevResearch.2.033394}},
  volume       = {{2}},
  year         = {{2020}},
}