TY - JOUR

T1 - Imperfect thermalizations allow for optimal thermodynamic processes

AU - Bäumer, Elisa

AU - Perarnau-Llobet, Martí

AU - Kammerlander, Philipp

AU - Wilming, Henrik

AU - Renner, Renato

N1 - Funding Information: We thank Guillem Perarnau, Matteo Lostaglio, Kamil Korzekwa, and Chris Perry for interesting discussions and useful comments on the manuscript. We acknowledge contributions from the Swiss National Science Foundation via the NCCR QSIT as well as project No. 200020_165843. M.P.-L. acknowledges support from the Alexander von Humboldt Foundation. All authors are grateful for support from the EU COST Action MP1209 on Thermodynamics in the Quantum Regime.

PY - 2019/6/24

Y1 - 2019/6/24

N2 - Optimal (reversible) processes in thermodynamics can be modelled as step-by-step processes, where the system is successively thermalized with respect to different Hamiltonians by an external thermal bath. However, in practice interactions between system and thermal bath will take finite time, and precise control of their interaction is usually out of reach. Motivated by this observation, we consider finite-time and uncontrolled operations between system and bath, which result in thermalizations that are only partial in each step. We show that optimal processes can still be achieved for any non-trivial partial thermalizations at the price of increasing the number of operations, and characterise the corresponding tradeoff. We focus on work extraction protocols and show our results in two different frameworks: A collision model and a model where the Hamiltonian of the working system is controlled over time and the system can be brought into contact with a heat bath. Our results show that optimal processes are robust to noise and imperfections in small quantum systems, and can be achieved by a large set of interactions between system and bath.

AB - Optimal (reversible) processes in thermodynamics can be modelled as step-by-step processes, where the system is successively thermalized with respect to different Hamiltonians by an external thermal bath. However, in practice interactions between system and thermal bath will take finite time, and precise control of their interaction is usually out of reach. Motivated by this observation, we consider finite-time and uncontrolled operations between system and bath, which result in thermalizations that are only partial in each step. We show that optimal processes can still be achieved for any non-trivial partial thermalizations at the price of increasing the number of operations, and characterise the corresponding tradeoff. We focus on work extraction protocols and show our results in two different frameworks: A collision model and a model where the Hamiltonian of the working system is controlled over time and the system can be brought into contact with a heat bath. Our results show that optimal processes are robust to noise and imperfections in small quantum systems, and can be achieved by a large set of interactions between system and bath.

UR - http://www.scopus.com/inward/record.url?scp=85094980884&partnerID=8YFLogxK

U2 - 10.22331/q-2019-06-24-153

DO - 10.22331/q-2019-06-24-153

M3 - Article

AN - SCOPUS:85094980884

VL - 3

JO - Quantum

JF - Quantum

SN - 2521-327X

ER -