Phase transitions and dynamics of one-dimensional solitons in spin-orbit-coupled Bose-Bose mixtures

TL;DR

This paper explores the formation, stability, and dynamics of one-dimensional solitons in spin-orbit-coupled Bose-Bose mixtures, revealing complex bifurcations, stability regions, and the influence of Lee-Huang-Yang corrections on ground states.

Contribution

It introduces the semi-dipole family of solitons, analyzes their bifurcations and stability, and highlights the role of LHY terms in shaping soliton properties in spin-orbit-coupled quantum gases.

Findings

Identification of semi-dipole solitons and their bifurcation behavior.

Discovery of complex wavefunction solitons as ground states due to LHY effects.

Mapping of stability regions with monostability, oscillations, and splitting phenomena.

Abstract

We investigate the formation, stability, and dynamics of solitons in a one-dimensional binary Bose-Einstein condensate under the action of the spin-orbit-coupling (SOC) and Lee-Huang-Yang (LHY) correction to the underlying system of the Gross-Pitaevskii equations. We identify the semi-dipole (SD) family of solitons and thoroughly analyze its properties. The numerical analysis reveals intricate bifurcations, including transitions from real to complex-valued stationary wavefunctions of the SD solitons and norm-dependent dynamical instabilities. Stability maps in the plane of the solitons' norm and interaction strength exhibit areas of monostability, oscillatory behavior, and soliton splitting. Solitons with complex stationary wavefunctions emerge as ground states in broad parameter areas, due to the effects of the LHY terms. The other soliton species, in the form of mixed modes (MMs), does not feature the compexification bifurcation. In the LHY-dominated regime, the SD and MM solitons exhibit identical values of the energy for the same norm. The results deepen the understanding of nonlinear matter-wave states and reveal multi-stable ones in quantum gases.