Solitons and Josephson-type oscillations in Bose-Einstein condensates with spin-orbit coupling and time-varying Raman frequency

Abstract

The existence and dynamics of solitons in quasi-one-dimensional Bose-Einstein condensates (BEC) with spin-orbit coupling (SOC) and attractive two-body interactions are described for two coupled atomic pseudo-spin components with slowly and rapidly varying time-dependent Raman frequency. By varying the Raman frequency linearly in time, it was shown that ordinary nonlinear Schrödingertype bright solitons can be converted to striped bright solitons and vice versa. The internal Josephson oscillations between atom-number of the coupled soliton components, and the corresponding center-of-mass motion, are studied for different parameter configurations. In this case, a mechanism to control the soliton parameters is proposed by considering parametric resonances, which can emerge when using time-varying Raman frequencies. Full numerical simulations confirm variational analysis predictions when applied to the region where regular solitons are expected. In the limit of high frequencies, the system is described by a time-averaged Gross-Pitaevskii formalism with renormalized nonlinear and SOC parameters and modified phase-dependent nonlinearities. By comparing full-numerical simulations with averaged results, we have also studied the lower limits for the frequency of Raman oscillations in order to obtain stable soliton solutions.

Information theoretic approach to effects of spin–orbit coupling in quasi-one-dimensional Bose–Einstein condensates

“…This will give us an opportunity to examine the role of spin-orbit coupling in localizing or de-localizing the atomic density distribution in BECs. The spectral properties noted here have also been found to play a role in studying localization properties of the ground state of SOC BEC [20,21] in optical lattices as well as in controlling Josephson-type oscillation between solitonic components [22] in the BEC.…”

Vector gap solitons of spin-orbit-coupled Bose-Einstein condensate in square optical lattice

“…Recently, the study of SOC-BEC has gained significant attention [13][14][15][16]. In terms of coupling, different forms of Rashba (inverse spin Hall effect in SOC systems) and Dresselhaus SOC [17], and a mixture of the former two, are realized [18]. SOC-BEC is interesting because it has a similar Dirac band structure [19].…”