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Stochastic thermodynamics offers a powerful formalism to study fluctuating thermodynamic variables, such as (free) energy, entropy, heat, and work in small systems driven beyond the linear response regime. Small electronic devices, such as single-electron boxes and quantum dots have been recently shown to provide well-controlled benchmarks for stochastic thermodynamics. In particular, it is possible to realize the ubiquitous concepts of a Szilard engine and a Maxwell’s demon in such systems. While stochastic thermodynamics gives a complete theoretical picture for devices such as the Maxwell’s demon at classical level, attempts to generalize the concept of work (and other thermodynamic quantities) to open quantum systems have met with some difficulties. The main problem in quantum mechanics is that there is no unique work operator, since for irreversible processes work depends both on the state of the system as well as the path taken. In this talk I will discuss the analysis of devices such as the Maxwell’s demon based on stochastic thermodynamics at the classical level. I will then describe some recent progress in defining work and its moments for quantum systems within the two-measurement protocol (TMP) approach, which for isolated systems coincides with the classical definition of work in the appropriate limit. In particular, I will show that using the TMP within the Linblad master equation formalism yields explicit results for driven, open quantum systems.

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Tapio Ala-Nissilä, Aalto University, Helsinki
TP seminar room 0.03
Contact: Joachim Krug