Density and pseudo-spin rotons in a bilayer of soft-core bosons [article]

Fatemeh Pouresmaeeli, Saeed H. Abedinpour, B. Tanatar
2021 arXiv   pre-print
We study the dynamics of a bilayer system of bosons with repulsive soft-core Rydberg-dressed interactions within the mean-field Bogoliubov-de Gennes approximation. We find roton minima in both symmetric and asymmetric collective density modes of the symmetric bilayer. Depending on the density of bosons in each layer and the spacing between two layers, the homogeneous superfluid phase becomes unstable in either (or both) of these two channels, leading to density and pseudo-spin-density wave
more » ... bilities in the system. Breaking the symmetry between two layers, either with a finite counterflow or a density imbalance renormalizes the dispersion of collective modes and makes the system more susceptible to density-wave instability.
arXiv:2112.05400v1 fatcat:uzr7tjnt6bgjjjfpojoz3yi4fe