Dynamics of quantum soliton in Lee-Huang-Yang spin-orbit coupled Bose-Einstein condensates

TL;DR

This paper investigates the structure and dynamics of quantum solitons in spin-orbit coupled Bose-Einstein condensates, revealing how quantum fluctuations and couplings influence soliton types, stability, and breathing behaviors.

Contribution

It provides analytical and numerical analysis of quantum solitons in spin-orbit coupled BECs, highlighting the effects of SO and Rabi couplings on soliton properties and dynamics.

Findings

Identification of quantum-bright and quantum-stripe solitons depending on couplings.

Analytical soliton solutions matching numerical results.

Breathing frequency scales with Rabi coupling as a power law with exponent ~0.16.

Abstract

We present the numerical results of the structure and dynamics of the self-bound ground state arising solely because of the presence of beyond mean field quantum fluctuation in spin-orbit coupled binary Bose-Einstein condensates in one dimension. Depending upon spin-obit (SO) and Rabi couplings, we observe that the ground state exhibits either quantum-bright (plane) or quantum-stripe soliton nature. We find an analytical soliton solution for non-zero SO coupling that matches quite well with the numerical results. Further, we investigate the dynamical stability of these solitons by adopting three protocols, such as (i) adding initial velocity to each component, (ii) quenching the SO and Rabi coupling parameters at initial and finite time, and (iii) allowing collision between the two spin-components by giving equal and opposite direction velocity to them. Many interesting dynamical features of the solitons, like, multi-fragmented, repelling, and breathing in time and space-time, are observed. For given Rabi coupling frequency, the breathing frequency of the soliton increases upon the increase in SO coupling, attaining a maximum at the critical SO coupling where the phase transition from the bright to stripe soliton occurs. We observe that the maximum breathing frequency exhibits power law dependence on the Rabi coupling frequency with an exponent $\sim 0.16$.