We show that the momentum distribution of a nonlinear matter wave suddenly
released with a finite velocity in a speckle potential converges, after an
out-of-equilibrium evolution, to a universal Rayleigh-Jeans thermal
distribution. By exploring the complete phase diagram of the equilibrated wave,
we discover that for low but nonzero values of the disorder strength, a
large-scale structure -a condensate- appears in the equilibrium distribution.Comment: 5 pages, 3 figures. Supplementary material adde