Description

October 20, 12.00, Salon de Grados

Dear colleagues:

I am pleased to welcome you to seminar of Prof. Boris Malomed
(Tel Aviv University) on Tuesday, October 20.

Title: Stable two-dimensional solitons in spin-orbit-coupled self-attractive Bose-Einstein condensates

Abstract

It is commonly known that two-dimensional mean-field models of optical and matter waves with cubic self-attraction cannot produce stable solitons in free space because of the occurrence of collapse in the same setting. By means of numerical analysis and variational approximation, we demonstrate that the two-component model of the Bose-Einstein condensate with the Rashba spin-orbit coupling (SOC) and cubic attractive interactions gives rise to stable solitary-vortex complexes of two types in the free space: semivortices  (SVs, with a vortex in one component and a fundamental soliton in the other), and mixed modes (MMs, with topological charges 0 and ±1 mixed in both components). The SVs and MMs realize the ground state of the system, provided that the self-attraction in the two components is, respectively, stronger or weaker than the cross attraction between them. The SVs and MMs which are not the ground states are subject to a drift instability. Moving free-space stable solitons are also found in the present non-Galilean-invariant system.

Additional results demonstrate similar solitons in the  one-dimensional and discrete two-dimensional versions of the SOC system.

The work was recently published in:

H. Sakaguchi, B. Li, and B. A. Malomed, "Creation of two-dimensional composite solitons in spin-orbit-coupled self-attractive Bose-Einstein condensates in free space", Phys. Rev. E 89, 032920 (2014);

H. Sakaguchi and B. A. Malomed, "Discrete and continuum composite solitons in Bose-Einstein condensates with the Rashba spin-orbit coupling in one and two dimensions", Phys. Rev. E 90, 062922 (2014).