Cross-over to quasi-condensation: mean-field theories and beyond

@article{Henkel2017CrossoverTQ,
title={Cross-over to quasi-condensation: mean-field theories and beyond},
author={C. Henkel and T. Sauer and N. Proukakis},
journal={Journal of Physics B},
year={2017},
volume={50},
pages={114002}
}

We analyze the cross-over of a homogeneous one-dimensional Bose gas from the ideal gas into the dense quasi-condensate phase. We review a number of mean-field theories, perturbative or self-consistent, and provide accurate evaluations of equation of state, density fluctuations, and correlation functions. A smooth crossover is reproduced by classical-field simulations based on the stochastic Gross-Pitaevskii equation, and the Yang-Yang solution to the one-dimensional Bose gas.