Gap Solitons in Spin-Orbit-Coupled Bose-Einstein Condensates in Optical Lattices

TL;DR

This paper investigates gap solitons in spin-orbit-coupled Bose-Einstein condensates with experimentally feasible coupling, revealing two families of solitons with distinct symmetry and polarization properties.

Contribution

It provides a detailed analysis of gap solitons in realistic spin-orbit-coupled BECs, highlighting symmetry effects and polarization features not previously explored.

Findings

Two families of gap solitons with opposite parity signs.

Solitons exhibit spin-polarization in broken parity cases.

Identification of fundamental modes in the energy gap.

Abstract

While different ways to realize spin-orbit coupling in Bose-Einstein condensates exist, not all are currently experimentally implementable. Here we present a detailed study of gap solitons in a Bose- Einstein condensate with experimentally realizable spin-orbit coupling and discuss two cases relating to a spin-dependent parity symmetry. In the parity symmetric case, two families of fundamental gap solitons in second linear energy gap are demonstrated with opposite sign of the parity, with one family having single humped densities and the other double humped ones. In the case of broken parity symmetry, the fundamental modes manifest spin-polarization. Both families possess an opposite sign of the spin-polarization.