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  • Open Access

Optimal finite-time thermodynamics of effective two-level systems

Alberto Rolandi*

  • Atominstitut, TU Wien, 1020 Vienna, Austria and Institute for Quantum Optics and Quantum Information - IQOQI Vienna, Austrian Academy of Sciences, Boltzmanngasse 3, A-1090 Vienna, Austria

  • *Contact author: alberto.rolandi@tuwien.ac.at

Phys. Rev. E 113, 044133 – Published 28 April, 2026

DOI: https://doi.org/10.1103/hv2n-5dcs

Abstract

The optimization of the conversion of thermal energy into work and the minimization of dissipation for nano- and mesoscopic systems is a complex challenge because of the important role fluctuations play on the dynamics of small systems. I generalize the work of Esposito et al. [Europhys. Lett. 89, 20003 (2010)] to optimize at all driving speeds the control needed to extract the maximum amount of work from any effective two-level systems. These emerge when one coarse grains degrees of freedom, which is often unavoidable to obtain “real-world” two-level systems. In particular, I allow even for the system to have underlying quantum dynamics, as long as these allow for a coarse graining that leads to a Markovian master equation. I analyze the finite-time thermodynamics of these systems and find the thermodynamically optimal protocols, which depend on the size of the coarse graining needed to obtain a two-level system. Furthermore, I use these results to derive speed limits for any transformation performed on an effective two-level system.

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