Photon-assisted electron tunnelling for environment engineering superconducting circuits

The effort in superconducting electronics is rising due to the demand of high-precision devices and the possibility to employ quantum effects for the purpose of detection, computing, and communication. Environment engineering is a powerful tool not only to improve the characteristics of such devices but also to study open quantum systems. To access these phenomena, we recently invented a quantum-circuit refrigerator (QCR) [1] which is based on the electron tunneling through the superconductor–insulator–normal-metal junctions. In this talk, I will give a brief overview of the recent research related to the QCR. This device not only enables us to cool down a superconducting circuit, but also to employ it as a photon source [2] or as a fast reset tool for the linear resonators and qubits [3]. Interestingly, the QCR allows us to control and to study fundamental physics phenomena such as the Lamb shift [4]. We theoretically predict that a replacement of the normal-metal island of the QCR with a quantum dot may lead to a narrow-band amplifier and an analogue of a maser. I will also describe some details related to the implementation of such a device for its practical utilization.
[1] M. Silveri et al, Phys. Rev. B 96, 094524 (2017); K. Y. Tan et al, Nat. Commun. 8, 15189 (2017).
[2] S. Masuda et al, Sci. Rep. 8, 3966 (2018); E. Hyyppä et al, Appl. Phys. Lett. 114, 192603 (2019).
[3] V. A. Sevriuk et al, Appl. Phys. Lett. 115, 082601 (2019); Hao Hsu et al, Phys. Rev. B 101, 235422 (2020).
[4] M. Silveri et al, Nat. Phys. 15, 533 (2019); Arto Viitanen et al arXiv:2008.08268 (2020).