Photon condensation in circuit QED by engineered dissipation

TL;DR

This paper demonstrates how engineered dissipation in circuit QED systems can induce photon condensation, creating a stationary out-of-equilibrium condensate through tailored photon-qubit interactions.

Contribution

It introduces a method to realize photon condensation in circuit QED by designing specific dissipative couplings, a novel approach to out-of-equilibrium quantum many-body states.

Findings

Engineered dissipation directs photons to low-momentum states.

A realistic setup for observing photon condensation is proposed.

The properties of the out-of-equilibrium condensate are characterized.

Abstract

We study photon condensation phenomena in a driven and dissipative array of superconducting microwave resonators. Specifically, we show that by using an appropriately designed coupling of microwave photons to superconducting qubits, an effective dissipative mechanism can be engineered, which scatters photons towards low-momentum states while conserving their number. This mimics a tunable coupling of bosons to a low temperature bath, and leads to the formation of a stationary photon condensate in the presence of losses and under continuous-driving conditions. Here we propose a realistic experimental setup to observe this effect in two or multiple coupled cavities, and study the characteristics of such an out-of-equilibrium condensate, which arise from the competition between pumping and dissipation processes.