Thermodynamics of micro- and nano-systems driven by periodic temperature variations

Seifert, Udo; Brandner, Kay; Saito, Keiji

Abstract

We introduce a general framework for analyzing the thermodynamics of small systems that are driven by both a periodic temperature variation and some external parameter modulating their energy. This setup covers, in particular, periodic micro- and nano-heat engines. In a first step, we show how to express total entropy production by properly identified time-independent affinities and currents without making a linear response assumption. In linear response, kinetic coefficients akin to Onsager coefficients can be identified. Specializing to a Fokker-Planck-type dynamics, we show that these coefficients can be expressed as a sum of an adiabatic contribution and one reminiscent of a Green-Kubo expression that contains deviations from adiabaticity. Furthermore, we show that the generalized kinetic coefficients fulfill an Onsager-Casimir-type symmetry tracing back to microscopic reversibility. This symmetry allows for nonidentical off-diagonal coefficients if the driving protocols are not symmetric under time reversal.We then derive a novel constraint on the kinetic coefficients that is sharper than the second law and provides an efficiency-dependent bound on power. As one consequence, we can prove that the power vanishes at least linearly when approaching Carnot efficiency.We illustrate our general framework by explicitly working out the paradigmatic case of a Brownian heat engine realized by a colloidal particle in a time-dependent harmonic trap subject to a periodic temperature profile. This case study reveals inter alia that our new general bound on power is asymptotically tight.

Citation

Seifert, U., Brandner, K., & Saito, K. (2015). Thermodynamics of micro- and nano-systems driven by periodic temperature variations. Physical Review X, 5(3), Article 031019. https://doi.org/10.1103/PhysRevX.5.031019

• Journal Article Type: Article
• Acceptance Date: Jun 29, 2015
• Online Publication Date: Aug 19, 2015
• Publication Date: Aug 19, 2015
• Deposit Date: Feb 26, 2020
• Publicly Available Date: Mar 20, 2020
• Journal: Physical Review X
• Electronic ISSN: 2160-3308
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 5
• Issue: 3
• Article Number: 031019
• DOI: https://doi.org/10.1103/PhysRevX.5.031019
• Public URL: https://nottingham-repository.worktribe.com/output/4038090