arXiv subjects

Jiangnan Biguo

Publications and source records attributed to Jiangnan Biguo.

3 recordsLinked to original sources

arXiv2026

Ferrodark soliton collisions: Breather formation, pair reproduction, and spin-mass separation

We study collisions between a ferrodark soliton (FDS) and an antiFDS ($\mathbb{Z}_2$ kinks in the spin order) in the easy-plane phase of spin-1 Bose-Einstein condensates (BECs). For a type-I pair (type-I FDS-antiFDS pair) at low incoming velocities, the pair annihilates followed by the formation of an extremely long-lived dissipative breather on a stable background, a spatially localized wave packet with out-of-phase oscillating magnetization and mass superfluid densities. Periodic emissions of spin and density waves cause breather energy dissipation and we find that the breather energy decays logarithmically in time. When the incoming velocity is larger than a critical velocity at which a stationary FDS-antiFDS pair forms, a pair with finite separating velocity is reproduced. When approaching the critical velocity from below, we find that the lifetime of the stationary type-I pair shows a power-law divergence, resembling a critical behavior. In contrast, a type-II pair (type-II FDS-antiFDS pair) never annihilates and only exhibits reflection. For collisions of a mixed type FDS-antiFDS pair, as $\mathbb{Z}_2$ kinks in the spin order, reflection occurs in the topological structure of the magnetization while the mass superfluid density profiles pass through each other, manifesting spin-mass separation.

cond-mat.quant-gas↗

arXiv2026

Unified Geometric Perspective for Spin-1 Systems: Bridging Nematic Director and Majorana Stars

We present a unified geometric approach for spin-1 systems that connects seemingly distinct geometric representations such as the nematic director, the Cartesian representation and the Majorana stellar representation. Starting from a product state of two distinguishable spin-1/2 particles, we provide a direct way to capture crucial geometric information. This perspective reveals the fundamental interplay between subspace projection and geometric constraints. This approach effectively maps magnetic solitons onto a kink model, allowing us to derive their equations of motion, a task not readily achieved with traditional methods. This simplified dynamical description reveals that the novel transition of these solitons in a harmonic trap corresponds to a fundamental transformation between kink and dip structures in the underlying geometry.

cond-mat.quant-gas↗

arXiv2025

Motion of ferrodark solitons in trapped superfluids: spin corrections and emergent oscillators

We propose a framework for topological soliton dynamics in trapped spinor superfluids, decomposing the force acting on the soliton by the surrounding fluid into the buoyancy force and spin corrections arising from the density depletion at soliton core and the coupling between the orbital motion and the spin mixing, respectively. Our formulation applies to large-amplitude soliton motion in general superfluids with spin degrees of freedom under arbitrary external potentials. For ferrodark solitons (FDSs) in spin-1 Bose-Einstein condensates , the spin correction could diverge, change the direction of the total force and enable mapping the FDS motion in a harmonic trap to the atomic-mass particle dynamics in an emergent quartic potential. Initially placing a type-I FDS near the trap center, a single-sided oscillation happens, which maps to the particle moving around a local minimum of the emergent double-well potential. As the initial distance of a type-II FDS from the trap center increases, the motion exhibits three regimes: trap-centered harmonic and anharmonic oscallations followed by single-sided oscillations. Correspondingly the emergent quartic potential undergoes a transition from a single minimum to a double-well shape, where the particle motion shifts from oscillating around the single minimum to crossing between two minima via the local maximum, then the symmetry-breaking motion around one of the two minima. In a hard-wall trap with linear potential, the FDS motion maps to a harmonic oscillator.

cond-mat.quant-gas↗