Abstract
We investigate theoretically a one-dimensional ideal Bose gas that is driven into a steady state far from equilibrium via the coupling to two heat baths: a global bath of temperature and a “hot needle,” a bath of temperature with localized coupling to the system. Remarkably, this system features a crossover to finite-size Bose condensation at temperatures that are orders of magnitude larger than the equilibrium condensation temperature. This counterintuitive effect is explained by a suppression of long-wavelength excitations resulting from the competition between both baths. Moreover, for sufficiently large needle temperatures ground-state condensation is superseded by condensation into an excited state, which is favored by its weaker coupling to the hot needle. Our results suggest a general strategy for the preparation of quantum degenerate nonequilibrium steady states with unconventional properties and at large temperatures.
- Received 29 May 2017
DOI:https://doi.org/10.1103/PhysRevLett.119.140602
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