Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2411.03893 · Photonics Research

Emulating a quantum Maxwell’s demon with nonseparable structured light

Edgar Medina-Segura, Paola Concha Obando, Light Mkhumbuza, Enrique J. Galvez, Carmelo Rosales‐Guzmán, Gianluca Ruffato, Filippo Romanato, Andrew Forbes, Isaac M. Nape

Published Aug 12, 2025• 4 citations
arXivHTMLPDF

Abstract

Maxwell’s demon (MD) has proven to be an instructive vehicle for exploring the relationship between information theory and thermodynamics. A long-standing debate has been the concern of entropy violation, now resolved by the introduction of a quantum MD that can enact reversible operations on a system. However, implementing it experimentally is challenging, as it demands precise control over multi-particle entangled states and the execution of entangling and disentangling operations with high accuracy. Here, we show how this can be emulated using vectorial structured light that is nonseparable in the spin and orbital angular momentum (OAM) internal degrees of freedom of each photon in a classical laser beam. We experimentally demonstrate that the demon’s classical entropy, linked to the uncertainty in spin degree of freedom of each photon, increases during the process while that in the system’s state (represented by OAM per photon) decreases. This is achieved by entangling the demon’s memory with the system, allowing the demon to acquire quantum information and utilize it to control the OAM states of the system after a disentangling operation. As a result, we demonstrate that the quantum demon can emulate the extraction of useful work from the system in the form of OAM, thereby opening a path to information-driven optical spanners for the mechanical rotation of objects using light. Our demonstration can easily be extrapolated to other degrees of freedom, for robust and scalable implementations of MDs at both the classical and quantum realms, enlightening the role of a structured light as a tool for exploiting principles in thermodynamics to control and measure information.

DOI
10.1364/prj.568160

Related papers

Experimental Rectification of Entropy Production by Maxwell’s Demon in a Quantum System

Patrice A. Camati, John P. S. Peterson, Tiago B. Batalhão +5 more

Maxwell's demon explores the role of information in physical processes. Employing information about microscopic degrees of freedom, this "intelligent observer" is capable of compensating entropy production (or extracting work), apparently challenging the second law of thermodynamics. In a modern standpoint, it is regarded as a feedback control mechanism and the limits of thermodynamics are recast incorporating information-to-energy conversion. We derive a trade-off relation between information-theoretic quantities empowering the design of an efficient Maxwell's demon in a quantum system. The demon is experimentally implemented as a spin-1/2 quantum memory that acquires information, and employs it to control the dynamics of another spin-1/2 system, through a natural interaction. Noise and imperfections in this protocol are investigated by the assessment of its effectiveness. This realization provides experimental evidence that the irreversibility in a nonequilibrium dynamics can be mitigated by assessing microscopic information and applying a feed-forward strategy at the quantum scale.

arXiv:1605.08821•Physical Review Letters•Dec 5, 2016•167 citations

Maxwell’s Demon Meets Nonequilibrium Quantum Thermodynamics

John Goold

Maxwell's demon explores the role of information in physical processes.Employing information about microscopic degrees of freedom, this "intelligent observer" is capable of compensating entropy production (or extracting work), apparently challenging the second law of thermodynamics.In a modern standpoint, it is regarded as a feedback control mechanism and the limits of thermodynamics are recast incorporating information-to-energy conversion.We derive a trade-off relation between information-theoretic quantities empowering the design of an efficient Maxwell's demon in a quantum system.The demon is experimentally implemented as a spin-1=2 quantum memory that acquires information, and employs it to control the dynamics of another spin-1=2 system, through a natural interaction.Noise and imperfections in this protocol are investigated by the assessment of its effectiveness.This realization provides experimental evidence that the irreversibility in a nonequilibrium dynamics can be mitigated by assessing microscopic information and applying a feed-forward strategy at the quantum scale.

Physics•Dec 5, 2016•2 citations

Observing a quantum Maxwell demon at work

Nathanaël Cottet, S. Jézouin, Landry Bretheau +7 more

In apparent contradiction to the laws of thermodynamics, Maxwell's demon is able to cyclically extract work from a system in contact with a thermal bath, exploiting the information about its microstate. The resolution of this paradox required the insight that an intimate relationship exists between information and thermodynamics. Here, we realize a Maxwell demon experiment that tracks the state of each constituent in both the classical and quantum regimes. The demon is a microwave cavity that encodes quantum information about a superconducting qubit and converts information into work by powering up a propagating microwave pulse by stimulated emission. Thanks to the high level of control of superconducting circuits, we directly measure the extracted work and quantify the entropy remaining in the demon's memory. This experiment provides an enlightening illustration of the interplay of thermodynamics with quantum information.

arXiv:1702.05161•Proceedings of the National Academy of Sciences•Jul 3, 2017•257 citations

A many-particle bosonic quantum Maxwell demon

Josef Hloušek, Tobias Denzler, Vojtěch Švarc +3 more

Energy extraction from a measured quantum system is a cornerstone of information thermodynamics as illustrated by Maxwell's demon. The nonequilibrium physics of many-particle systems is additionally strongly influenced by quantum statistics. We here report the first experimental realization of a quantum demon in a many-particle photonic setup made of two identical thermal light beams. We show that single-photon measurements combined with feedforward operation may deterministically increase the mean energy of one beam faster than energy fluctuations, thus improving the thermodynamic stability of the device. We moreover demonstrate that bosonic statistics can enhance the energy output above the classical limit, and further analyze the counterintuitive thermodynamics of the demon using an information-theoretic approach. Our results underscore the pivotal role of many-particle statistics for enhanced energy extraction in quantum thermodynamics.

arXiv:2412.03241•Dec 4, 2024•0 citations

Realization of Quantum Maxwell’s Demon with Solid-State Spins *

W.-B. Wang, X.-Y. Chang, F. Wang +9 more

We report experimental realization of a quantum version of Maxwell's demon using solid state spins where the information acquiring and feedback operations by the demon are achieved through conditional quantum gates. A unique feature of this implementation is that the demon can start in a quantum superposition state or in an entangled state with an ancilla observer. Through quantum state tomography, we measure the entropy in the system, demon, and the ancilla, showing the influence of coherence and entanglement on the result. A quantum implementation of Maxwell's demon adds more controllability to this paradoxical thermal machine and may find applications in quantum thermodynamics involving microscopic systems.

arXiv:1711.10101•Chinese Physics Letters•Apr 1, 2018•9 citations

Photon Angular-Momentum-Entropy Conversion (PASEC): A Theoretical Framework for Information-Thermodynamic Bridge in Structured Light

Jincheng Zhang

The unification of information theory and thermodynamics represents one of the most profound intellectual achievements in modern physics, historically bridged by principles such as Landauer's erasure bound and Szilard's engine. Concurrently, the exploration of structured light has revealed that photons can carry well-defined orbital angular momentum (OAM), opening vast multidimensional state spaces for optical communication, quantum information processing, and optical manipulation. In this paper, we propose the Photon Angular-Momentum-Entropy Conversion (PASEC) framework, establishing a rigorous theoretical foundation that demonstrates a direct, reversible, and quantitative conversion between the mechanical orbital angular momentum of light and information entropy. By conceptualizing programmable optical phase transformations as thermodynamic state functions, we derive the fundamental governing equations for PASEC, showing that changes in the OAM spectrum map directly onto Shannon and von Neumann entropy variations under constraint conditions. This formulation bypasses the traditional necessity of thermal dissipation for entropy changes, offering an alternative purely mechanical-informational pathway. We explore the thermodynamic consistency of the framework, formulating a generalized optical Landauer principle where spatial mode compression and expansion act as thermodynamic compression and expansion cycles. Finally, we discuss the profound implications of establishing photon angular-momentum thermodynamics, outlining pathways toward macroscopic quantum entropy control using modern programmable spatial light modulators and metasurfaces.

•Aug 11, 2026•0 citations
Maxwell’s demon (MD) has proven to be an instructive vehicle for exploring the relationship between information theory and thermodynamics. A long-standing debate has been the concern of entropy violation, now resolved by the introduction of a quantum MD that can enact reversible operations on a system. However, implementing it experimentally is challenging, as it demands precise control over multi-particle entangled states and the execution of entangling and disentangling operations with high accuracy. Here, we show how this can be emulated using vectorial structured light that is nonseparable in the spin and orbital angular momentum (OAM) internal degrees of freedom of each photon in a classical laser beam. We experimentally demonstrate that the demon’s classical entropy, linked to the uncertainty in spin degree of freedom of each photon, increases during the process while that in the system’s state (represented by OAM per photon) decreases. This is achieved by entangling the demon’s memory with the system, allowing the demon to acquire quantum information and utilize it to control the OAM states of the system after a disentangling operation. As a result, we demonstrate that the quantum demon can emulate the extraction of useful work from the system in the form of OAM, thereby opening a path to information-driven optical spanners for the mechanical rotation of objects using light. Our demonstration can easily be extrapolated to other degrees of freedom, for robust and scalable implementations of MDs at both the classical and quantum realms, enlightening the role of a structured light as a tool for exploiting principles in thermodynamics to control and measure information.
Maxwell's demon explores the role of information in physical processes. Employing information about microscopic degrees of freedom, this "intelligent observer" is capable of compensating entropy production (or extracting work), apparently challenging the second law of thermodynamics. In a modern standpoint, it is regarded as a feedback control mechanism and the limits of thermodynamics are recast incorporating information-to-energy conversion. We derive a trade-off relation between information-theoretic quantities empowering the design of an efficient Maxwell's demon in a quantum system. The demon is experimentally implemented as a spin-1/2 quantum memory that acquires information, and employs it to control the dynamics of another spin-1/2 system, through a natural interaction. Noise and imperfections in this protocol are investigated by the assessment of its effectiveness. This realization provides experimental evidence that the irreversibility in a nonequilibrium dynamics can be mitigated by assessing microscopic information and applying a feed-forward strategy at the quantum scale.
Maxwell's demon explores the role of information in physical processes.Employing information about microscopic degrees of freedom, this "intelligent observer" is capable of compensating entropy production (or extracting work), apparently challenging the second law of thermodynamics.In a modern standpoint, it is regarded as a feedback control mechanism and the limits of thermodynamics are recast incorporating information-to-energy conversion.We derive a trade-off relation between information-theoretic quantities empowering the design of an efficient Maxwell's demon in a quantum system.The demon is experimentally implemented as a spin-1=2 quantum memory that acquires information, and employs it to control the dynamics of another spin-1=2 system, through a natural interaction.Noise and imperfections in this protocol are investigated by the assessment of its effectiveness.This realization provides experimental evidence that the irreversibility in a nonequilibrium dynamics can be mitigated by assessing microscopic information and applying a feed-forward strategy at the quantum scale.
In apparent contradiction to the laws of thermodynamics, Maxwell's demon is able to cyclically extract work from a system in contact with a thermal bath, exploiting the information about its microstate. The resolution of this paradox required the insight that an intimate relationship exists between information and thermodynamics. Here, we realize a Maxwell demon experiment that tracks the state of each constituent in both the classical and quantum regimes. The demon is a microwave cavity that encodes quantum information about a superconducting qubit and converts information into work by powering up a propagating microwave pulse by stimulated emission. Thanks to the high level of control of superconducting circuits, we directly measure the extracted work and quantify the entropy remaining in the demon's memory. This experiment provides an enlightening illustration of the interplay of thermodynamics with quantum information.
Energy extraction from a measured quantum system is a cornerstone of information thermodynamics as illustrated by Maxwell's demon. The nonequilibrium physics of many-particle systems is additionally strongly influenced by quantum statistics. We here report the first experimental realization of a quantum demon in a many-particle photonic setup made of two identical thermal light beams. We show that single-photon measurements combined with feedforward operation may deterministically increase the mean energy of one beam faster than energy fluctuations, thus improving the thermodynamic stability of the device. We moreover demonstrate that bosonic statistics can enhance the energy output above the classical limit, and further analyze the counterintuitive thermodynamics of the demon using an information-theoretic approach. Our results underscore the pivotal role of many-particle statistics for enhanced energy extraction in quantum thermodynamics.
We report experimental realization of a quantum version of Maxwell's demon using solid state spins where the information acquiring and feedback operations by the demon are achieved through conditional quantum gates. A unique feature of this implementation is that the demon can start in a quantum superposition state or in an entangled state with an ancilla observer. Through quantum state tomography, we measure the entropy in the system, demon, and the ancilla, showing the influence of coherence and entanglement on the result. A quantum implementation of Maxwell's demon adds more controllability to this paradoxical thermal machine and may find applications in quantum thermodynamics involving microscopic systems.
The unification of information theory and thermodynamics represents one of the most profound intellectual achievements in modern physics, historically bridged by principles such as Landauer's erasure bound and Szilard's engine. Concurrently, the exploration of structured light has revealed that photons can carry well-defined orbital angular momentum (OAM), opening vast multidimensional state spaces for optical communication, quantum information processing, and optical manipulation. In this paper, we propose the Photon Angular-Momentum-Entropy Conversion (PASEC) framework, establishing a rigorous theoretical foundation that demonstrates a direct, reversible, and quantitative conversion between the mechanical orbital angular momentum of light and information entropy. By conceptualizing programmable optical phase transformations as thermodynamic state functions, we derive the fundamental governing equations for PASEC, showing that changes in the OAM spectrum map directly onto Shannon and von Neumann entropy variations under constraint conditions. This formulation bypasses the traditional necessity of thermal dissipation for entropy changes, offering an alternative purely mechanical-informational pathway. We explore the thermodynamic consistency of the framework, formulating a generalized optical Landauer principle where spatial mode compression and expansion act as thermodynamic compression and expansion cycles. Finally, we discuss the profound implications of establishing photon angular-momentum thermodynamics, outlining pathways toward macroscopic quantum entropy control using modern programmable spatial light modulators and metasurfaces.