arXiv:2601.07011

Irreversibility of decorrelating processes: an experimental assessment in cavity QED

Guillaume Cœuret Cauquil, Patrice A. Camati, Irénée Frerot, Zheng Tan, Alexia Auffèves, Igor Dotsenko

quant-phSubmitted Jan 11, 2026• Announced Jan 13, 2026• 0 citations• Revised May 25, 2026 (v2)

Abstract

Entropy production quantifies the amount of irreversibility of a physical process, leading to fundamental bounds for thermodynamic quantities. It captures the inability to run a physical system forward and then backward, bringing it to the same initial state. Considerable research has been carried out in the last decades to extend entropy production to non-equilibrium quantum processes. We experimentally investigate the entropy production of such forward-backward cycles affected by genuinely quantum irreversibility. Namely, we consider processes realized to erase different types of correlations between two interacting systems, from obliterating solely quantum coherence to completely decorrelating local states. This makes the measurement of entropy production experimentally challenging. Addressing this challenge is the purpose of this paper.

Comments: 11 pages, 6 figures

Related papers

Reconstructing quantum entropy production to probe irreversibility and correlations

Stefano Gherardini, Matthias M Müller, Andrea Trombettoni +2 more

Abstract One of the major goals of quantum thermodynamics is the characterization of irreversibility and its consequences in quantum processes. Here, we discuss how entropy production provides a quantification of the irreversibility in open quantum systems through the quantum fluctuation theorem. We start by introducing a two-time quantum measurement scheme, in which the dynamical evolution between the measurements is described by a completely positive, trace-preserving (CPTP) quantum map (forward process). By inverting the measurement scheme and applying the time-reversed version of the quantum map, we can study how this backward process differs from the forward one. When the CPTP map is unital, we show that the stochastic quantum entropy production is a function only of the probabilities to get the initial measurement outcomes in correspondence of the forward and backward processes. For bipartite open quantum systems we also prove that the mean value of the stochastic quantum entropy production is sub-additive with respect to the bipartition (except for product states). Hence, we find a method to detect correlations between the subsystems. Our main result is the proposal of an efficient protocol to determine and reconstruct the characteristic functions of the stochastic entropy production for each subsystem. This procedure enables to reconstruct even others thermodynamical quantities, such as the work distribution of the composite system and the corresponding internal energy. Efficiency and possible extensions of the protocol are also discussed. Finally, we show how our findings might be experimentally tested by exploiting the state of-the-art trapped-ion platforms.

arXiv:1706.02193Quantum Science and TechnologyMay 25, 201821 citations

The role of quantum coherence in non-equilibrium entropy production

Jader P. Santos, Lucas C. Céleri, Gabriel Teixeira Landi +1 more

Abstract Thermodynamic irreversibility is well characterized by the entropy production arising from non-equilibrium quantum processes. We show that the entropy production of a quantum system undergoing open-system dynamics can be formally split into a term that only depends on population unbalances, and one that is underpinned by quantum coherences. This allows us to identify a genuine quantum contribution to the entropy production in non-equilibrium quantum processes. We discuss how these features emerge both in Lindblad-Davies differential maps and finite maps subject to the constraints of thermal operations. We also show how this separation naturally leads to two independent entropic conservation laws for the global system-environment dynamics, one referring to the redistribution of populations between system and environment and the other describing how the coherence initially present in the system is distributed into local coherences in the environment and non-local coherences in the system-environment state. Finally, we discuss how the processing of quantum coherences and the incompatibility of non-commuting measurements leads to fundamental limitations in the description of quantum trajectories and fluctuation theorems.

arXiv:1707.08946npj Quantum InformationMar 1, 2019185 citations

Identifying contributions of classical and quantum correlations to entropy production in non-equilibrium quantum processes

Xu-Cai Zhuang, Qing-Feng Xue, Qi Zhang +3 more

Abstract Entropy production plays a pivotal role in characterizing the inherent irreversibility of non-equilibrium quantum processes, and a thorough understanding of this concept holds immense potential for advancing the design of thermodynamically efficient quantum technologies. In this work, we demonstrate that the entropy production observed in multipartite open quantum systems, undergoing independent dissipations, arises from two sources: the local dynamics governing individual subsystems and the non-local correlations embedded within the system. The contributions of quantum correlations, as genuine quantum effects, to entropy production are identified explicitly. The revelation of the source of entropy production is substantiated by an analysis of its stochastic counterpart, derived from quantum trajectories. Furthermore, we propose an experimentally feasible scheme to isolate the contributions of both classical and quantum correlations to entropy production. The theoretical findings are simulated using an optical setup. Our work establishes a profound connection between thermodynamic and informational quantities, elucidating the source of irreversibility in the non-equilibrium process of multipartite quantum systems and the genuine quantum contribution therein.

Quantum Science and TechnologyJul 10, 20251 citation

Experimental Determination of Irreversible Entropy Production in out-of-Equilibrium Mesoscopic Quantum Systems

Matteo Brunelli, Lorenzo Fusco, Renate Landig +9 more

By making use of a recently proposed framework for the inference of thermodynamic irreversibility in bosonic quantum systems, we experimentally measure and characterize the entropy production rates in the nonequilibrium steady state of two different physical systems-a micromechanical resonator and a Bose-Einstein condensate-each coupled to a high finesse cavity and hence also subject to optical loss. Key features of our setups, such as the cooling of the mechanical resonator and signatures of a structural quantum phase transition in the condensate, are reflected in the entropy production rates. Our work demonstrates the possibility to explore irreversibility in driven mesoscopic quantum systems and paves the way to a systematic experimental assessment of entropy production beyond the microscopic limit.

arXiv:1602.06958Physical Review LettersOct 17, 201888 citations

Evidence of genuine quantum effects in nonequilibrium entropy production via quantum photonics

Qing-Feng Xue, Xu-Cai Zhuang, Deyang Duan +5 more

Entropy production is a fundamental concept that plays a crucial role in the second law of thermodynamics and the measure of irreversibility. It imposes rigorous constraints on the kinds of transformations allowed in thermodynamic processes. Using an optical setup, here we experimentally demonstrate the division of entropy production of an open quantum system into a population-related component and a coherence-related component, supporting previous theoretical predictions. The coherence-related component represents a genuine quantum contribution with no classical counterpart. By adjusting bath temperatures and initial coherences of the system, we first derive the total entropy production due to both populations and coherences, then remove all the coherences of the system to solely obtain the population-related contribution. The difference between these two results permits to isolate the coherence-related term. Based on this division, our experiment ultimately provides proof of principle that irreversibility at the quantum level can be reduced through properly harnessing the two contributions to entropy production.

arXiv:2402.06858Physical Review AOct 4, 20242 citations

Coherent feedback-enhanced asymmetry of thermal process in open quantum systems: Cavity optomechanics

Hamza Harraf, Mohamed Amazioug, Rachid Ahl Laamara

Entropy production is a fundamental concept in nonequilibrium thermodynamics, providing a direct measure of the irreversibility inherent in any physical process. In this work, we investigate in steady-state the enhancement of irreversibility employing coherent feedback loop. We evaluate the steady-state entropy production rate and quantum correlations by applying the quantum phase space formulation to calculate the entropy change. Our study reveals the essential contribution of coherent feedback in the thermal bath's input-noise operators, resulting in the system being driven far from thermal equilibrium. Our analysis shows that in the small-coupling limit, the entropy production rate is proportional to the quantum mutual information. We use for application the optomechanical system of Fabry-Pérot cavity, and show that the picks of the entropy production corresponding of the heating/cooling of movable mirror are improved. Therefore, we conclude that irreversibility and quantum correlations are not independent and must be analyzed jointly. The results demonstrate the possibility of enhancement of entropy production and pave the way for promising quantum thermal applications through coherent feedback loop.

quant-pharXiv:2512.13288Dec 16, 2025