Negative mass hydrodynamics in a Spin-Orbit--Coupled Bose-Einstein Condensate
Abstract
A negative effective mass can be realized in quantum systems by engineering the dispersion relation. A powerful method is provided by spin-orbit coupling, which is currently at the center of intense research efforts. Here we measure an expanding spin-orbit coupled Bose-Einstein condensate whose dispersion features a region of negative effective mass. We observe a range of dynamical phenomena, including the breaking of parity and of Galilean covariance, dynamical instabilities, and self-trapping. The experimental findings are reproduced by a single-band Gross-Pitaevskii simulation, demonstrating that the emerging features - shockwaves, soliton trains, self-trapping, etc. - originate from a modified dispersion. Our work also sheds new light on related phenomena in optical lattices, where the underlying periodic structure often complicates their interpretation.
Cite
@article{arxiv.1612.04055,
title = {Negative mass hydrodynamics in a Spin-Orbit--Coupled Bose-Einstein Condensate},
author = {M. A. Khamehchi and Khalid Hossain and M. E. Mossman and Yongping Zhang and Th. Busch and Michael McNeil Forbes and P. Engels},
journal= {arXiv preprint arXiv:1612.04055},
year = {2017}
}
Comments
9 pages, 6 figures: Minor updated bringing this in line with published version