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Mechanical work extraction from an error-prone active dynamic Szilard engine
by Luca Cocconi, Paolo Malgaretti, Holger Stark
This is not the latest submitted version.
Submission summary
| Authors (as registered SciPost users): | Luca Cocconi · Paolo Malgaretti |
| Submission information | |
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| Preprint Link: | scipost_202505_00051v2 (pdf) |
| Date submitted: | Sept. 3, 2025, 4:32 p.m. |
| Submitted by: | Luca Cocconi |
| Submitted to: | SciPost Physics |
| Ontological classification | |
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| Academic field: | Physics |
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| Approach: | Theoretical |
Abstract
Isothermal information engines operate by extracting net work from a single heat bath through measurement and feedback control. In this work, we analyze a realistic active Szilard engine operating on a single self-propelled particle by means of steric interaction with an externally controlled mechanical element. In particular, we provide a comprehensive study of how finite measurement accuracy affects the engine's work and power output, as well as the cost of operation. Having established the existence of non-trivial optima for work and power output, we study the dependence of their loci on the measurement error parameters and identify conditions for their positivity under one-shot and cyclic engine operation. We also demonstrate that a suitably defined efficiency of information-to-work conversion, which at equilibrium is bounded above by unity as a consequence of Landauer's principle, may here be made arbitrarily large by increasing the active Péclet number of the particle. Notably, the information efficiency for one-shot operation exhibits a discontinuous transition and a non-monotonic dependence on the measurement precision. Finally, we show that cyclic operation improves information efficiency by harvesting residual mutual information between successive measurements.
Author indications on fulfilling journal expectations
- Provide a novel and synergetic link between different research areas.
- Open a new pathway in an existing or a new research direction, with clear potential for multi-pronged follow-up work
- Detail a groundbreaking theoretical/experimental/computational discovery
- Present a breakthrough on a previously-identified and long-standing research stumbling block
Author comments upon resubmission
List of changes
Main changes: - Expanded discussion on physical motivation in the introduction - Clarify link between Landauer bound and the second law of thermodynamics out of equilibrium - Added a table of key parameters (Appendix A) and provided reference values (footnote 2) motivating our focus on the high Péclet regime - Added discussion of positional noise for particle-piston encounter dynamics - Added discussion of delay in piston placement - Revised Sec.4.2 to give a more general argument in support of the approximations applied there
Current status:
Reports on this Submission
Report #2 by Klaus Kroy (Referee 1) on 2025-10-10 (Invited Report)
- Cite as: Klaus Kroy, Report on arXiv:scipost_202505_00051v2, delivered 2025-10-09, doi: 10.21468/SciPost.Report.12097
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Author: Luca Cocconi on 2025-10-27 [id 5954]
(in reply to Report 2 by Klaus Kroy on 2025-10-10)We have included an additional sentence in the abstract to address this concern. In particular, it is now mentioned explicitly that for a nonequilibrium information efficiency to be bounded above by unity one would need to account for nonthermal motion of the bath particles as an operational cost. Having said this, we find our definition of efficiency (work extracted over operational cost of measurement by an observed interacting with the active bath) physically meaningful and sufficiently motivated in the manuscript.