Localized modes in dense repulsive and attractive Bose-Einstein condensates with spin-orbit and Rabi couplings

TL;DR

This paper investigates localized modes in dense binary Bose-Einstein condensates with spin-orbit and Rabi couplings, revealing how these interactions influence mode shapes and collapse thresholds through numerical and analytical methods.

Contribution

It derives 1D coupled equations with nonpolynomial nonlinearity from 3D models and analyzes the effects of spin-orbit and Rabi couplings on localized modes in dense condensates.

Findings

Spin-orbit and Rabi couplings distort mode shapes with side lobes.

Couplings reduce collapse threshold in attractive condensates.

Mode profiles are obtained numerically and analytically.

Abstract

We consider a binary Bose-Einstein condensate with linear and nonlinear interactions between its components, which emulate the spinor system with spin-orbit (SO) and Rabi couplings. For a relatively dense condensate, 1D coupled equations with the nonpolynomial nonlinearity of both repulsive and attractive signs are derived from the 3D Gross-Pitaevskii equations. Profiles of modes confined in an external potential under the action of the self-repulsion, and self-trapped solitons in the case of the self-attraction, are found in a numerical form and by means of analytical approximations. In the former case, the interplay of the SO and Rabi couplings with the repulsive nonlinearity strongly distorts shapes of the trapped modes, adding conspicuous side lobes to them. In the case of the attractive nonlinearity, the most essential result is reduction of the collapse threshold under the action of the SO and Rabi couplings.