Spectroscopy of the two unequal superconducting resonators coupled via transmon qubit for the realization of the quantum heat engine

Progress in both superconducting circuit QED experiments and ultrasensitive nanoscale bolometry provide a unique platform for studying heat transport in the quantum limit, towards the realization of quantum heat engines and refrigerators [1,2]. Transmon qubits coupled to superconducting resonators have been considered as promising candidates for realizing such quantum systems, such as the recently demonstrated quantum heat valve [3]. This work is devoted to study both theoretically and experimentally the transmission spectrum of the resonator-qubit-resonator assembly, in both the equal (valve) and unequal (engine) resonators regimes. For the realization of the quantum heat engine, we study the flux-tunable photonic heat transport in the resonator-qubit-resonator assembly with unequal resonators terminated by mesoscopic normal-metal reservoirs. Additionally, a means to characterize a superconducting resonator shunted with a highly dissipative normal metal bolometer is presented.
References:
[1] R. Kosloff and A. Levy, Annual Rev. Phys. Chem. 65, 365 (2014).
[2] B. Karimi and J. P. Pekola, Phys. Rev. B 94, 184503 (2016).
[3] A. Ronzani et al., Nature Physics 14, p.991 (2018).