Minimal dissipation with active baths in weakly driven processes (2503.10920v1)

Abstract: Although vastly studied, white noise is just an ideal case of heat baths, which limits us from real-world scenarios. Understanding the underlying thermodynamics of active heat baths is therefore a demanding task, mainly in optimal control. This work investigates such a scenario for finite-time weakly driven processes, observing how the relaxation function changes from the passive to the active case. In particular, we show that the relaxation time modifies according to the active heat bath, bringing the system far from the passive heat bath case from the non-equilibrium point of view. Optimal protocols to minimize the average work and its fluctuation are immediately derived from such observation. Conditions on the kernel are determined to guarantee that the active system also obeys the Second Law of Thermodynamics. Brownian motions subject to harmonic traps with Ornstein-Uhlenbeck baths exemplify our results.

Minimal Dissipation with Active Baths in Weakly Driven Processes

This paper by Pierre Naz and Fabrício Q. Potiguar explores the thermodynamics of active heat baths, particularly in the context of weakly driven processes. The authors address the limitations of modeling real-world scenarios using idealized white noise as the representation of heat baths, proposing instead a framework that considers active baths characterized by non-Markovian features such as colored noise.

Key Concepts and Findings

• Active Heat Baths: Unlike traditional passive heat baths exemplified by white noise, active baths arise in systems far from equilibrium, where self-propelled motion is significant. The authors model these active baths using colored noise, such as that from Ornstein-Uhlenbeck processes, which better captures the memory effects and correlations inherent in active systems.
• Relxation Function and Time: A crucial result of the paper is the demonstration that the relaxation function and relaxation time are significantly affected when active baths are considered. For systems under harmonic confinement, the relaxation time was found to be extended by the persistence time of the active noise, thereby shifting the system further from equilibrium compared to passive thermal baths.
• Thermodynamic Laws: The research ensures that even with the introduction of active baths, the modeled system adheres to the Second Law of Thermodynamics. Conditions are derived on the kernel used in the Langevin equation to maintain thermodynamic consistency.
• Optimal Protocols: By adjusting for the altered relaxation times due to active baths, the paper extends recent developments in optimal control theory. These adaptations yield protocols that minimize work and its fluctuations. The theoretical framework establishes the groundwork for potential experimental realizations that can take advantage of the inherently non-equilibrium nature of active baths for optimized performance.

Implications and Future Directions

The inclusion of active bath dynamics in thermodynamic models presents both practical and theoretical implications. Practically, understanding these dynamics allows for the refinement of protocols used in micro and nanoscale systems, such as those found in biological systems or synthetic active matter scenarios, to minimize energy dissipation.

Theoretical advancements outlined in the paper could further influence the design of experiments, where different active bath characteristics might be leveraged to control system response more effectively. Future developments could explore alternative noise models, expanding upon the colored noise approximation or introducing inertia effects, and more complex interactions between active particles.

Overall, the paper underscores the importance of considering non-idealized conditions in thermodynamics, especially within the context of emerging active matter paradigms. This work suggests that the framework and results presented could significantly impact how future experiments and models integrate active processes to achieve minimal dissipation, thereby broadening the understanding and application of non-equilibrium thermodynamic systems.