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TT: Fachverband Tiefe Temperaturen

TT 84: Fluctuations and Noise

TT 84.1: Talk

Thursday, March 15, 2018, 09:30–09:45, HFT-FT 131

Thermodynamic Bounds on Dissipation in Open Quantum Systems — •Paul Menczel, Christian Flindt, and Kay Brandner — Department of Applied Physics, Aalto University, 00076 Aalto, Finland

Given today's rapid experimental advances in quantum engineering, it becomes increasingly important to understand the laws that govern thermodynamic processes far from equilibrium in nano-scale devices. For an open quantum system under weak coupling conditions, we derive universal lower bounds on the total dissipation accompanying such a process. Going beyond the second law, our bounds are expressed in terms of the photon exchange between the system and its environment. As a key application of our approach, we obtain a new trade-off relation between power and efficiency of periodically driven quantum heat engines. This bound becomes weakest for semi-classical engine cycles that do not involve superpositions between the energy levels of the working substance. Showing that cycles with coherence inevitably come at the price of increased dissipation, our results are relevant for current experimental efforts to realize thermal machines in the quantum realm.