Influence of Rashba spin–orbit and Rabi couplings on the spin-mixing and ground state phases of binary Bose–Einstein condensates

Abstract

We study the miscibility properties and ground state phases of two-component spin-orbit (SO) coupled Bose-Einstein condensates (BECs) in a harmonic trap with strong axial confinement. By numerically solving the coupled Gross-Pitaevskii equations in the two-dimensional setting, we analyze the SO-coupled BECs for two possible permutations of the intra- and interspecies interactions, namely (i) weak intra- and weak interspecies interactions (W-W) and (ii) weak intra- and strong interspecies interactions (W-S). Considering the density overlap integral as a miscibility order parameter, we investigate the miscible-immiscible transition by varying the coupling parameters. We obtain various ground state phases, including plane wave, half quantum vortex, elongated plane wave, and different stripe wave patterns for W-W interactions. For finite Rabi coupling, an increase in SO coupling strength leads to the transition from the fully miscible to the partially miscible state. We also characterize different ground states in the coupling parameter space using the root mean square sizes of the condensate. The spin density vector for the ground state phases exhibits density, quadrupole and dipole like spin polarizations. For the W-S interaction, in addition to that observed in the W-W case, we witness semi vortex, mixed mode, and shell-like immiscible phases. We notice a wide variety of spin polarizations, such as density, dipole, quadrupole, symbiotic, necklace, and stripe-like patterns for the W-S case. A detailed investigation in the coupling parameter space indicates immiscible to miscible state phase transition upon varying the Rabi coupling for a fixed Rashba SO coupling. The critical Rabi coupling for the immiscible-miscible phase transition decreases upon increasing the SO coupling strength.

Exploring the role of beyond mean-field interaction in the structure and dynamics of one-dimensional quantum droplets

“…The ground state is obtained by numerically solving the coupled GP equations (2a) and (2b) using the imaginary time method with the aid of split-step Crank-Nicolson scheme [28,39,40]. We consider the box size for all the simulations as [−153.6:153.6] with a spatial resolution of dx = 0.025.…”

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

“…Overall we see that the double quench protocol provides more stability to the solitons. This particular feature is one of the promising potential application for quan-tum information and quantum computing, which based on mixing and demixing of qubits [34,35]. As we perform the first quenching same as previous case while in second quench only change in Rabi frequency is executed with Ω = 0 → 5 at t = 10 we find the appearance of moving BS with generation of the second harmonics [see Fig.…”