Phase Transitions in a Bose-Hubbard Model with Cavity-Mediated Global-Range Interactions
Abstract
We study a system with competing short- and global-range interactions in the framework of the Bose-Hubbard model. Using a mean-field approximation we obtain the phase diagram of the system and observe four different phases: a superfluid, a supersolid, a Mott insulator and a charge density wave, where the transitions between the various phases can be either of first or second order. We qualitatively support these results using Monte-Carlo simulations. An analysis of the low-energy excitations shows that the second-order phase transition from the charge density wave to the supersolid is associated with the softening of particle- and hole-like excitations which give rise to a gapless mode and an amplitude Higgs mode in the supersolid phase. This amplitude Higgs mode is further transformed into a roton mode which softens at the supersolid to superfluid phase transition.
Cite
@article{arxiv.1604.00865,
title = {Phase Transitions in a Bose-Hubbard Model with Cavity-Mediated Global-Range Interactions},
author = {N. Dogra and F. Brennecke and S. D. Huber and T. Donner},
journal= {arXiv preprint arXiv:1604.00865},
year = {2016}
}