Cavity Optomechanics Demonstrates Coherent Feedback Control of Entropy Production in Open Quantum Systems

Entropy production, a key measure of irreversibility in physical processes, receives significant attention from researchers seeking to understand systems far from equilibrium. Hamza Harraf, Mohamed Amazioug, and Rachid Ahl Laamara, from universities in Morocco, now demonstrate how coherent feedback loops actively enhance this irreversibility within open quantum systems. Their work reveals that incorporating coherent feedback into the thermal environment drives systems further from thermal equilibrium, and importantly, establishes a direct link between entropy production rate and mutual information. By applying their findings to an optomechanical system, the team shows that this approach improves the heating and cooling of a movable mirror, opening up promising avenues for novel thermal applications and a deeper understanding of the relationship between irreversibility and correlations.

Coherent feedback-enhanced asymmetry of thermal process in open quantum systems: Cavity optomechanics Entropy production is a fundamental concept in nonequilibrium thermodynamics, providing a direct measure of the irreversibility inherent in physical processes. This work investigates whether coherent feedback can enhance the asymmetry of thermal processes in open quantum systems, specifically within the framework of cavity optomechanics. The research demonstrates that implementing a coherent feedback loop significantly increases entropy production compared to systems without such control. This enhancement arises from the ability to manipulate the quantum state of the system, driving it further from equilibrium and amplifying the irreversibility of the thermal cycle. The study details a theoretical framework and numerical simulations that reveal the conditions under which maximal entropy production can be achieved, offering insights into controlling thermodynamic processes at the quantum level and exploring novel applications in quantum heat engines and refrigerators.

The researchers evaluate the steady-state entropy production rate and quantum correlations by applying a quantum phase space formulation to calculate the entropy change. The analysis reveals that coherent feedback on the thermal bath’s input-noise operators drives the system far from thermal equilibrium, and in the small-coupling limit, the entropy production rate is proportional to the quantum mutual information, indicating a direct relationship between these two properties.

Quantum Correlations and Thermodynamic Irreversibility

This research demonstrates that coherent feedback loops can enhance irreversibility in systems of coupled quantum oscillators, directly impacting entropy production. By applying a phase space formulation and analyzing the steady-state entropy production rate, the team revealed a fundamental connection between entropy production and correlations within the system. Specifically, the study establishes that, in certain conditions, the rate of entropy production is proportional to the mutual information between the coupled oscillators, highlighting that these two properties are intrinsically linked and should not be considered independently. The researchers applied their findings to an optomechanical system, demonstrating improved heating and cooling of a movable mirror through the enhancement of entropy production via coherent feedback.

This suggests potential applications in thermal technologies and control. The authors acknowledge that their analysis relies on certain approximations, particularly concerning the small-coupling limit, and that further investigation is needed to explore the behavior of the system under stronger coupling conditions. Future work could focus on extending the analysis to more complex systems and exploring the potential for utilizing these principles to develop novel thermal devices with enhanced efficiency and control.

Entropy Production Links to Quantum Correlations

This research demonstrates that coherent feedback loops can enhance irreversibility in systems of coupled quantum oscillators, directly impacting entropy production. By applying a phase space formulation and analyzing the steady-state entropy production rate, the team revealed a fundamental connection between entropy production and correlations within the system. Specifically, the study establishes that, in certain conditions, the rate of entropy production is proportional to the mutual information between the coupled oscillators, highlighting that these two properties are intrinsically linked and should not be considered independently. The researchers applied their findings to an optomechanical system, demonstrating improved heating and cooling of a movable mirror through the enhancement of entropy production via coherent feedback.

This suggests potential applications in thermal technologies and control. The authors acknowledge that their analysis relies on certain approximations, particularly concerning the small-coupling limit, and that further investigation is needed to explore the behavior of the system under stronger coupling conditions. Future work could focus on extending the analysis to more complex systems and exploring the potential for utilizing these principles to develop novel thermal devices with enhanced efficiency and control.