Dynamics and formation of vortices collapsed from ring dark solitons in a two-dimensional spin–orbit coupled Bose–Einstein condensate

We consider the dynamics and formation of vortices from ring dark solitons in a two-dimensional Bose–Einstein condensate with the Rashba spin–orbit coupling based on the time-dependent coupled Gross–Pitaevskii equation. Compared with previous results, the system exhibits complex dynamical behaviors in the presence of the spin–orbit coupling. With the modulation of the spin–orbit coupling, not only the lifetime of ring dark solitons is greatly prolonged, but also their attenuation kinetics is significantly affected. For two shallow ring dark solitons with the equal strength of the spin–orbit coupling, the radius of ring dark solitons increases to a maximum value over time and then shrinks into a minimum value. Due to the effect of the snake instability, ring dark solitons split into a series of ring-like clusters of vortex pairs, which perform complex oscillations. This indicates that the system is strongly dependent on the presence of the spin–orbit coupling. Furthermore, the effect of different initial modulation depths on the dynamics of ring dark solitons is investigated.     

Exact soliton solutions of spinor Bose-Einstein condensates

We study matter-wave solitons in Bose-Einstein condensates of ultracold gaseous atoms with spin degrees of freedom and present a class of exact solutions based on the inverse scattering method. The one-soliton solutions are classified with respect to the spin states. We analyze collisional effects between solitons in the same or different spin state(s), which reveals a very interesting possibility: we can manipulate the spin dynamics by controlling the parameters of colliding solitons.     

Composite multihump vector solitons carrying topological charge

We propose composite solitons carrying topological charge: multicomponent two dimensional [ (2+1)D] vector (Manakov-like) solitons for which at least one component carries topological charge. These multimode solitons can have a single hump or exhibit a multihump structure. The "spin" carried by these multimode composite solitons suggests 3D soliton interactions in which the particlelike behavior includes spin, in addition to effective mass, linear, and angular momenta.     

Nonlinear dynamics of a quasi-one-dimensional spiral structure

The nonlinear dynamics of solitons and spin waves in spiral magnets without inversion centers is investigated using the sine-Gordon model. The possibility of finding solitons in spiral structures is discussed.     

Dark solitons in ferromagnetic chains with first- and second-neighbor interactions

We present a study of the ferromagnetic spin chain with both first- and second-neighbor interactions. We obtain the condition for the appearance and stability of bright and dark solitons for arbitrary wave number in the Brillouin zone. The influence of the second-neighbor interaction and the anisotropy on the soliton properties is considered. The scattering of dark solitons from point defects in the discrete spin chain is investigated numerically.     

Observation of spin-wave envelope solitons in periodic magnetic film structures

The formation and propagation of light and dark microwave spin-wave envelope solitons in a periodic magnetic film structure have been observed. The periodic structure was manufactured on the basis of the single-crystal film of iron-yttrium garnet and a lattice of copper strips placed on the surface of the film perpendicularly to the propagation direction of carrying spin waves. The solitons are generated at frequencies corresponding to the band gap in the spectrum of the spin waves of the periodic structure, which is due to the first Bragg resonance.     

Observation of spin-wave envelope Dark solitons in ferromagnetic films

Microwave spin-wave envelope dark solitons were experimentally observed for the first time. Dark solitons with zero minimum amplitude were generated by two-frequency excitation of input spin waves with a fixed amplitude. Nonlinear interaction between these two traveling waves gave rise to periodic sequences of dark solitons in a ferromagnetic film.     

Dynamics of topological solitons in two-dimensional ferromagnets

Dynamical topological solitons are studied in classical two-dimensional Heisenberg easy-axis ferromagnets. The properties of such solitons are treated both analytically in the continuum limit and numerically by spin dynamics simulations of the discrete system. Excitation of internal mode causes orbital motion. This is confirmed by simulations.     

Bright soliton dynamics in Fourier synthesized optical lattice

We consider the dynamics of bright solitons in one dimensional Bose Einstein condensate with spin orbit coupling and trapped by an optical lattice potential. We mainly focus on the effects of the spin orbit coupling, Rabi coupling and detuning parameter on the soliton dynamics. The solution of the coupled Gross Pitaevskii equation is performed with the help of the variational and numerical methods for various parameters. The population imbalance and the center of mass motion show different dynamic behaviors depending on the parameters. We also obtain traveling bright solitons related with a given finite initial momentum.     

Envelope solitons in a medium with strong nonlinear damping

The formation of microwave spin-wave envelope solitons in the ferrite film of yttrium iron garnet in the presence of strong nonlinear damping has been experimentally found and investigated. The solitons are formed due to the four-wave interactions of spin waves when the characteristic time of wave modulation-instability development is much shorter than the time for establishing the generation of short-wavelength magnons. The presence of nonlinear damping allows the excitation of spin-wave envelope solitons by means of long microwave pulses.     

Bell’s Theorem and Entangled Solitons

Entangled solitons construction being introduced in the nonlinear spinor field model, the Einstein—Podolsky—Rosen (EPR) spin correlation is calculated and shown to coincide with the quantum mechanical one for the 1/2–spin particles.     

Statistics of Yang-Mills solitons

We determine the statistics and the spin of isolated Yang-Mills monopoles in eigenstates of their electric and magnetic charge. Exchange of solitons is defined using the translation operator of a companion paper; and under exchange, state vectors representingN identical solitons change sign precisely when the angular momentum of each soliton is half-integral.     

Ground states, solitons and spin textures in spin-1 Bose-Einstein condensates

We present an overview of our recent theoretical studies on the quantum phenomena of the spin-1 Bose-Einstein condensates, including the phase diagram, soliton solutions and the formation of the topological spin textures. A brief exploration of the effects of spin-orbit coupling on the ground-state properties is given. We put forward proposals by using the transmission spectra of an optical cavity to probe the quantum ground states: the ferromagnetic and polar phases. Quasi-one-dimension solitons and ring dark solitons are studied. It is predicted that characteristics of the magnetic solitons in optical lattice can be tuned by controlling the long-range light-induced and static magnetic dipoledipole interactions; solutions of single-component magnetic and single-, two-, three-components polar solitons are found; ring dark solitons in spin-1 condensates are predicted to live longer lifetimes than that in their scalar counterparts. In the formation of spin textures, we have considered the theoretical model of a rapidly quenched and fast rotating trapped spin-1 Bose-Einstein condensate, whose dynamics can be studied by solving the stochastic projected Gross-Pitaevskii equations. Spontaneous generation of nontrivial topological defects, such as the hexagonal lattice skyrmions and square lattice of half-quantized vortices was predicted. In particular, crystallization of merons (half skyrmions) can be generated in the presence of spin-orbit coupling.     

Two types of ground-state bright solitons in a coupled harmonically trapped pseudo-spin polarization Bose-Einstein condensate

We study two types of bright solitons in an attractive Bose-Einstein condensate with a spin-orbit interaction. By solving the coupled nonlinear Schr odinger equations with the variational method and the imaginary time evolution method,fundamental properties of solitons are carefully investigated in different parameter regimes. It is shown that the detuning between the Raman beam and energy states of the atoms dominates the ground state type and spin polarization strength.The soliton dynamics is also studied for various moving velocities for zero and nonzero detuning cases. We find that the shape of individual component solitons can be maintained when the moving speed of solitons is low and the detuning is small in the coupled harmonically trapped pseudo-spin polarization Bose-Einstein condensate.     

Quantum fluctuations in Sine-Gordon like magnetic chains: Corrections to soliton energies

The effect of quantum fluctuations on solitons in the easy-plane ferromagnetic chain is considered within the semiclassical approximation. In accordance with the low temperature ideal gas picture we treat the solitons as a Boltzmann gas and impose quantisation on the spin wave spectrum. We present a method which allows to calculate quantum corrections in a systematic perturbation expansion in 1/S, whereS is the spin length. We use this method to obtain the soliton energy to second order at zero temperature. Our results indicate that the semiclassical approach reasonably describes quantum effects on soliton properties.     

Observation of the amplification of spin-wave envelope solitons in ferromagnetic films by parallel magnetic pumping

The propagation of envelope solitons of microwave-frequency spin waves in a spatially periodic field oriented parallel to the magnetic pump has been investigated experimentally. In a pulsed pumping regime with amplitude much greater than the threshold for parametric excitation of spin systems, amplification of spin-wave envelope solitons exceeding their natural damping was obtained. Pis’ma Zh. éksp. Teor. Fiz. 66, No. 5, 346–350 (10 September 1997)     

Magnetized vector solitons in a spin-orbit coupled spin-1 Bose-Einstein condensate with Zeeman coupling

The property of matter-wave vector solitons in a spin-1 Bose-Einstein condensate with spin-orbit and Zeeman couplings is investigated by multiscale perturbation method. The excitation spectrum and the corresponding state vectors of the system are obtained analytically, and they can be adjusted by the parameters of the system. The bright and dark vector solitons are formulated by reducing the three-component coupled Gross-Pitaeviskii equations to a standard nonlinear Schrödinger equation, which has the solutions of the bright and dark solitons with positive or negative mass depending on the product of the effective dispersive and nonlinear coefficients. The moving vector solitons are demonstrated by adjusting specific momentum near the energy minimum. Finally, the magnetized features of the vector solitons are discussed by the spin polarization of the system.     

Optical spin generated by a soliton pulse in an add–drop filter for optoelectronic and spintronic use

A new concept of an optical spin generation using bright and dark soliton conversion behaviors within a modified optical add–drop filter known as PANDA ring resonator is proposed. The orthogonal solitons can be formed within the system and detected simultaneously at the output ports. Under the resonant condition, the dark and bright soliton pair corresponding to the left-hand and right-hand rotating solitons (photons) can be generated. When a soliton is absorbed by an object, an angular momentum of either +? or ?? is imparted to the object, in which two possible spin states known as optoelectronic(soliton) spins are exhibited. Furthermore, an array of soliton spins, i.e. particles can be generated and detected by the proposed system, which can be used to form large scale spin generation.     

Self-generation of spin-wave envelope soliton trains with different periods

The self-generation of periodic spin-wave envelope soliton trains of microwave spin waves in active rings based on ferromagnetic films is studied experimentally. The trains of bright solitons with different periods are self-generated in the same ring due to the frequency-selective control of the attenuation of spin waves circulating in an active ring.