arXiv:1908.10021 · Physical Review Letters
Collisionally Inhomogeneous Bose-Einstein Condensates with a Linear Interaction Gradient
Andrea Di Carli, Grant W. Henderson, Stuart Flannigan, Craig D. Colquhoun, Matthew Mitchell, Gian‐Luca Oppo, Andrew J. Daley, Stefan Kuhr, Elmar Haller
Abstract
We study the evolution of a collisionally inhomogeneous matter wave in a spatial gradient of the interaction strength. Starting with a Bose-Einstein condensate with weak repulsive interactions in quasi-one-dimensional geometry, we monitor the evolution of a matter wave that simultaneously extends into spatial regions with attractive and repulsive interactions. We observe the formation and the decay of solitonlike density peaks, counterpropagating self-interfering wave packets, and the creation of cascades of solitons. The matter-wave dynamics is well reproduced in numerical simulations based on the nonpolynomial Schrödinger equation with three-body loss, allowing us to better understand the underlying behavior based on a wavelet transformation. Our analysis provides new understanding of collapse processes for solitons, and opens interesting connections to other nonlinear instabilities.