Quantum Heat Valve

LTL Quantum Physics Seminar (Nanotalo). Speaker: Dr. Alberto Ronzani (Aalto University, Finland).

We present the realization of a fundamental functional element: a thermal valve. In our implementation, thermal reservoirs are realized as nanofabricated normal-metal resistors acting as dissipative terminations for two equivalent quarterwave microwave resonators. The controllable element is a Trasmon-type qubit, capacitively coupled between the two resonators. We characterize the temperature of the "drain" reservoir as a function of the thermal bias applied to the "source" reservoir and of the modulation of the qubit excitation energy. The latter is set by the application of a static magnetic field. We identify and explain two qualitatively different working regimes, depending on the competition between the reservoir-resonator and resonator-qubit coupling rates.