On the number of Bose-selected modes in driven-dissipative ideal Bose gases

Abstract

In an ideal Bose gas that is driven into a steady state far from thermal equilibrium, a generalized form of Bose condensation can occur. Namely, the single-particle states unambiguously separate into two groups: the group of Bose-selected states, whose occupations increase linearly with the total particle number, and the group of all other states whose occupations saturate [Phys. Rev. Lett. 111, 240405 (2013)PRLTAO0031-900710.1103/PhysRevLett.111.240405]. However, so far very little is known about how the number of Bose-selected states depends on the properties of the system and its coupling to the environment. The answer to this question is crucial since systems hosting a single, a few, or an extensive number of Bose-selected states will show rather different behavior. While in the former two scenarios each selected mode acquires a macroscopic occupation, corresponding to (fragmented) Bose condensation, the latter case rather bears resemblance to a high-temperature state of matter. In this paper, we systematically investigate the number of Bose-selected states, considering different classes of the rate matrices that characterize the driven-dissipative ideal Bose gases in the limit of weak system-bath coupling. These include rate matrices with continuum limit, rate matrices of chaotic driven systems, random rate matrices, and rate matrices resulting from thermal baths that couple to a few observables only.

Floquet-state cooling

“…In countless situations of basic experimental and theoretical interest, ranging from superconducting charge pumps [1] over Dirac fermions in graphene coupled to acoustic phonons [2] and quantum-dot devices [3] to superconductors under phonon driving [4], emitters in laserdriven cavities [5], or few-level systems coupled to transmission lines [6], one encounters periodically driven quantum systems interacting with their environment [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Such systems usually adopt a quasistationary state which may depend substantially on that interaction, even to the extent that the dynamics are fully environment-governed [1].…”

Topologically robust zero-sum games and Pfaffian orientation: How network topology determines the long-time dynamics of the antisymmetric Lotka-Volterra equation

“…Whether a state becomes a condensate or a depleted state depends on the antisymmetric matrix A alone. This theoretical observation can be understood as a generalization of the Bose-Einstein condensation in thermodynamic equilibrium to a condensation of bosons in nonequilibrium [14], which has stimulated further research recently [67][68][69][70][71].…”

Bistability and nonequilibrium condensation in a driven-dissipative Josephson array: a c-field model

“…While the basic features of each branch could therefore be understood, a cohesive theoretical description of the system within a single model is currently lacking, and several interesting observations remain unexplained. In particular, in the lower branch of the bistability region a critical slowing down was observed, suggesting the occurrence of a nonequilibrium condensation phenomenon [6,17,27] possibly akin to exciton-polariton condensation [4,28]. Additionally, the critical dissipation observed in the superfluid phase was considerably smaller than was predicted by the simple single-mode theory [4].…”