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Hongguang Liang

Publications and source records attributed to Hongguang Liang.

3 recordsLinked to original sources

Spin Faraday Waves in Periodically Modulated Spin-Orbit-Coupled Bose Gases

This paper investigates the formation of Spin Faraday waves in spin-orbit-coupled Bose-Einstein condensate under the stripe phase and explores the dispersion relation under three different phases. We discover that the SFW exhibit temporal and spatial patterns when the interaction is modulated periodically, and appear with resonant waves and higher order harmonics. SFW can be excited even when the modulation frequency resonates with the trap frequency. Furthermore, we study the dispersion relation of these Faraday modes through periodic modulation, which agrees well with our theoretical results under three quantum phases. Our work indicates novel physical phenomena originating from the introduction of spin-orbit coupling and provides a possible method for studying the dispersion of Bose gases.

cond-mat.quant-gas

Spin Faraday pattern formation in a circular spin-orbit coupled Bose-Einstein condensate with stripe phase

We investigate the spin Faraday pattern formation in a periodically driven, pancake-shaped spin-orbit-coupled (SOC) Bose-Einstein condensate (BEC) prepared with stripe phase. By modulating atomic interactions using in-phase and out-of-phase protocols, we observe collective excitation modes with distinct rotational symmetries (L-fold). Crucially, at the critical modulation frequency, out-of-phase modulation destabilizes the L = 6 pattern, whereas in-phase modulation not only preserves high symmetry but also excites higher-order modes. Unlike conventional binary BECs, Faraday patterns emerge here without initial noise due to SOC-induced symmetry breaking, with all patterns exhibiting supersolid characteristics. Furthermore, we demonstrate control over pattern symmetry, radial nodes, and pattern radius by tuning the modulation frequency, providing a new approach for manipulating quantum fluid dynamics. This work establishes a platform for exploring supersolidity and nonlinear excitations in SOC systems with stripe phase.

cond-mat.quant-gas

Expansion dynamics of Bose-Einstein condensates in a synthetic magnetic field

We investigate the expansion dynamics of spin-orbit-coupled Bose-Einstein condensates subjected to a synthetic magnetic field, after their release from an external harmonic trap. Our findings reveal that the condensate experiences a spin-dependent rotation and separation due to the rigid-like rotational velocity field, which leads to a spin density deflection. The deflection angle reaches a peak at a time that is inversely related to the frequency of the harmonic trap. When the detuning gradient is below a critical value for vortex nucleation, our analytical results derived from a spinor hydrodynamic theory align closely with numerical results using the coupled Gross-Pitaevskii equations. Beyond this critical value, we also numerically simulated the expansion dynamics of the condensates containing vortices with negative circulation. Our findings highlight the pivotal role of the rigid-like rotational velocity field on the dynamics of the condensate and may stimulate further experimental investigations into the rich superfluid dynamics induced by synthetic magnetic fields.

cond-mat.quant-gas