Direct temperature readout in nonequilibrium quantum thermometry

• URL: http://arxiv.org/abs/2601.07198v2
• Date: Sat, 17 Jan 2026 04:49:21 GMT
• Title: Direct temperature readout in nonequilibrium quantum thermometry
• Authors: Yan Xie, Junjie Liu,
• Abstract summary: We develop a direct temperature readout scheme based on a thermodynamic inference strategy.<n>We validate the corrected dynamical temperature in a qubit-based thermometer under a range of nonequilibrium initial states.
• Score: 12.105664915167843
• License: http://creativecommons.org/licenses/by-sa/4.0/
• Abstract: Quantum thermometry aims to measure temperature in nanoscale quantum systems, paralleling classical thermometry. However, temperature is not a quantum observable, and most theoretical studies have therefore concentrated on analyzing fundamental precision limits set by the quantum Fisher information through the quantum Cramer-Rao bound. In contrast, whether a direct temperature readout can be achieved in quantum thermometry remains largely unexplored, particularly under the nonequilibrium conditions prevalent in real-world applications. To address this, we develop a direct temperature readout scheme based on a thermodynamic inference strategy. The scheme integrates two conceptual developments: (i) By applying the maximum entropy principle with the thermometer's mean energy as a constraint, we assign a reference temperature to the nonequilibrium thermometer. We demonstrate that this reference temperature outperforms a commonly used effective temperature defined through equilibrium analogy. (ii) We obtain positive semi-definite error functions that lower-bound the deviation of the reference temperature from the true temperature-in analogy to the quantum Cramer-Rao bound for the mean squared error-and vanish upon thermalization with the sample. Combining the reference temperature with these error functions, we introduce a notion of corrected dynamical temperature which furnishes a postprocessed temperature readout under nonequilibrium conditions. We validate the corrected dynamical temperature in a qubit-based thermometer under a range of nonequilibrium initial states, confirming its capability to estimate the true temperature. Importantly, we find that increasing quantum coherence can enhance the precision of this readout.

Related papers

• Coherence-enhanced single-qubit thermometry out of equilibrium [0.0]
  We consider a finite-dimensional quantum system, employed as a quantum thermometer, in contact with a thermal inducing Markov bathian thermalization dynamics. We prove that the sensitivity of the thermometer, quantified by the quantum Fisher information, is enhanced by the quantum coherence in its initial state.
  arXiv  Detail & Related papers  (2024-05-23T11:11:01Z)
• Topological quantum thermometry [0.0]
  An optimal local quantum thermometer saturates the fundamental lower bound for the thermal state temperature estimation accuracy.<n>We show that the optimal local quantum thermometer can be realized in an experimentally feasible system of spinless fermions confined in a one-dimensional optical lattice.
  arXiv  Detail & Related papers  (2023-11-24T14:49:44Z)
• Demonstrating Quantum Microscopic Reversibility Using Coherent States of Light [58.8645797643406]
  We propose and experimentally test a quantum generalization of the microscopic reversibility when a quantum system interacts with a heat bath. We verify that the quantum modification for the principle of microscopic reversibility is critical in the low-temperature limit.
  arXiv  Detail & Related papers  (2022-05-26T00:25:29Z)
• Non-Markovian quantum thermometry [11.884385161872164]
  We propose non-Markovian quantum thermometry to measure the temperature of a quantum reservoir. It is found that it is the quantum criticality of the total thermometer-reservoir system that causes this enhanced sensitivity.
  arXiv  Detail & Related papers  (2021-09-06T09:39:08Z)
• Uhlmann Fidelity and Fidelity Susceptibility for Integrable Spin Chains at Finite Temperature: Exact Results [68.8204255655161]
  We show that the proper inclusion of the odd parity subspace leads to the enhancement of maximal fidelity susceptibility in the intermediate range of temperatures. The correct low-temperature behavior is captured by an approximation involving the two lowest many-body energy eigenstates.
  arXiv  Detail & Related papers  (2021-05-11T14:08:02Z)
• Role of topology in determining the precision of a finite thermometer [58.720142291102135]
  We find that low connectivity is a resource to build precise thermometers working at low temperatures. We compare the precision achievable by position measurement to the optimal one, which itself corresponds to energy measurement.
  arXiv  Detail & Related papers  (2021-04-21T17:19:42Z)
• Taking the temperature of a pure quantum state [55.41644538483948]
  Temperature is a deceptively simple concept that still raises deep questions at the forefront of quantum physics research. We propose a scheme to measure the temperature of such pure states through quantum interference.
  arXiv  Detail & Related papers  (2021-03-30T18:18:37Z)
• Adiabatic Sensing Technique for Optimal Temperature Estimation using Trapped Ions [64.31011847952006]
  We propose an adiabatic method for optimal phonon temperature estimation using trapped ions. The relevant information of the phonon thermal distributions can be transferred to the collective spin-degree of freedom. We show that each of the thermal state probabilities is adiabatically mapped onto the respective collective spin-excitation configuration.
  arXiv  Detail & Related papers  (2020-12-16T12:58:08Z)
• Non-equilibrium readiness and accuracy of Gaussian Quantum Thermometers [0.0]
  We show how quantum entanglement can enhance the readiness of composite Gaussian thermometers. We show that non-equilibrium conditions do not guarantee the best sensitivities in temperature estimation.
  arXiv  Detail & Related papers  (2020-05-05T18:00:01Z)
• Out-of-equilibrium quantum thermodynamics in the Bloch sphere: temperature and internal entropy production [68.8204255655161]
  An explicit expression for the temperature of an open two-level quantum system is obtained. This temperature coincides with the environment temperature if the system reaches thermal equilibrium with a heat reservoir. We show that within this theoretical framework the total entropy production can be partitioned into two contributions.
  arXiv  Detail & Related papers  (2020-04-09T23:06:43Z)
• Tight bound on finite-resolution quantum thermometry at low temperatures [0.0]
  We investigate fundamental precision limits for thermometry on cold quantum systems. We derive a tight bound on the optimal precision scaling with temperature, as the temperature approaches zero.
  arXiv  Detail & Related papers  (2020-01-13T08:13:42Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.