Refrigeration of a 1D gas of microwave photons

Abstract:We discuss a conceptually simple scheme for cooling a one dimensional gas of microwave photons in a superconducting transmission line. By shunting one end of the transmission line by a nonlinear Josephson element, we show how a cooling mechanism can be engineered that transfers photons from high- into low-frequency modes, while preserving their total number. We evaluate the resulting nonequilibrium steady state of the photon gas, which arises from a competition between this engineered cooling process and the natural, number non-conserving thermalization with the surrounding bath. Our analysis predicts that for realistic experimental parameters, this mechanism can be used to prepare photonic gases at sub-millikelvin temperatures, considerably below the typical base temperature of a dilution refrigerator. In addition, the system exhibits a new type of condensation transition that does not occur in the corresponding equilibrium scenario. As an outlook, we discuss potential applications of this cooling approach for quantum simulation schemes with interacting microwave photons.

Quantum Physics (quant-ph); Mesoscale and Nanoscale Physics (cond-mat.mes-hall)

Phys. Rev. A 114, 022604 (2026)

arXiv:2512.17530 [quant-ph]

(or arXiv:2512.17530v2 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2512.17530 Focus to learn more arXiv-issued DOI via DataCite

https://doi.org/10.1103/7n7h-6w2p Focus to learn more DOI(s) linking to related resources

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