Title: Towards quantum thermodynamics in electric circuits

Abstract:
I discuss non-equilibrium fluctuation relations (FRs) in the context of
electric circuits. Possibility to control and detect single electrons
enables us to assess FRs in these systems. I will discuss both the
theoretical aspects and experiments on FRs in them. Recently we have been
able to realize experimentally a Maxwell demon (Szilard engine) in such a
circuit, and to test the generalized Jarzynski equality (Sagawa-Ueda
equality) that includes the influence of mutual information in a feedback
protocol. Experimentally, up to 75% of kT log 2 heat per cycle could be
extracted from the bath in this experiment. Superconducting qubits provide
a testbed for investigating FRs in open quantum systems. I discuss these
systems, the quantum trajectory (quantum jump) method to analyze them, and
the status of our experiment based on single-photon calorimetry.