- Letter
Controlling nonequilibrium Bose-Einstein condensation with engineered environments
Phys. Rev. A 110, L021701 – Published 23 August, 2024
DOI: https://doi.org/10.1103/PhysRevA.110.L021701
Abstract
Out of thermal equilibrium, bosonic quantum systems can undergo Bose condensation away from the ground state, featuring a macroscopic occupation of an excited state or even of multiple states in the so-called Bose-selection scenario. In previous work, a theory was developed that predicts in which states a driven-dissipative ideal Bose gas condenses. Here we address the inverse problem: Given a target state with desired condensate fractions in certain single-particle states, how can this configuration be achieved by tuning available control parameters? Which type of experimental setup allows for flexible condensation control? We solve these problems, on the one hand, by proposing a Bose condenser, experimentally implementable in a superconducting circuit, where targeted Bose condensation into eigenstates of a chain of resonators is driven through the coupling to artificial quantum baths, realized via auxiliary two-level systems. On the other hand, we develop a theory to solve the inverse problem based on linear-programming methods. We further discuss the engineering of transition points between different Bose condensation configurations, which may find application in amplification, heat-flow control, and the design of highly structured quantum baths.
