We report on the static and dynamical properties of multiple dark-antidark solitons (DADs) in two-component, repulsively interacting Bose-Einstein condensates. Motivated by experimental observations involving multiple DADs, we present a theoretical study which showcases that bound states consisting of dark (antidark) solitons in the first (second) component of the mixture exist for different values of interspecies interactions. It is found that ensembles of few DADs may exist as stable configurations, while for larger DAD arrays, the relevant windows of stability with respect to the interspecies interaction strength become progressively narrower. Moreover, the dynamical formation of states consisting of alternating DADs in the two components of the mixture is monitored. A complex dynamical evolution of these states is observed, leading either to sorted DADs or to beating dark-dark solitons depending on the strength of the interspecies coupling. This study demonstrates clear avenues for future investigations of DAD configurations.
We unveil the dynamical formation of multiple localized structures in the form of dark-bright and dark-antidark solitary waves that emerge upon quenching a one-dimensional particle-imbalanced Bose-Bose mixture. Interspecies interaction quenches drive the system out-of-equilibrium while the so-called miscible/immiscible threshold is crossed in a two directional manner. Dark-bright entities are spontaneously generated for quenches towards the phase separated regime and dark-antidark states are formed in the reverse process. The distinct mechanisms of creation of the aforementioned states are dis…
We consider a one-dimensional trapped spin-1 Bose gas and numerically explore families of its solitonic solutions, namely antidark-dark-antidark (ADDAD), as well as dark-antidark-dark (DADD) solitary waves. Their existence and stability properties are systematically investigated within the experimentally accessible easy-plane ferromagnetic phase by means of a continuation over the atom number as well as the quadratic Zeeman energy. It is found that ADDADs are substantially more dynamically robust than DADDs. The latter are typically unstable within the examined parameter range. The dynamical e…
We investigate magnetic solitons in an immiscible binary Bose-Einstein condensate (BEC), where the intraspecies interactions are slightly weaker than the interspecies interactions. While their density and phase profiles are analogous to dark-bright solitons, other characteristic properties such as velocities, widths, total density depletions, and in-trap oscillations are different. In the low velocity regime, a magnetic soliton reduces to a traveling pair of magnetic domain walls. Collisional behaviors of the solitons are also briefly discussed. We further demonstrate that these solitonic stat…
Thermalization in a quenched one-dimensional antiferromagnetic spin-1 Bose gas is shown to proceed via a non-thermal fixed point through annihilation of Flemish-string bound states of magnetic solitons. A possible experimental situation is discussed.
Most experimental observations of solitons are limited to one-dimensional (1D) situations, where they are naturally stable. For instance, in 1D cold Bose gases, they exist for any attractive interaction strength $g$ and particle number $N$. By contrast, in two dimensions, solitons appear only for discrete values of $gN$, the so-called Townes soliton being the most celebrated example. Here, we use a two-component Bose gas to prepare deterministically such a soliton: Starting from a uniform bath of atoms in a given internal state, we imprint the soliton wave function using an optical transfer to…
Two-dimensional bright and dark-in-bright dipolar Bose-Einstein condensate solitons on a one-dimensional optical lattice
研究了一维光格势场中各向异性、稳定、亮偶极和亮中暗偶极准二维玻色-爱因斯坦凝聚体（BEC）孤子的静态和动力学性质.这些孤子在垂直于一维OL陷阱的平面内运动，可以同时具有排斥和吸引的接触相互作用。明中暗孤子是亮孤子的激发态。孤子，当受到一个小的扰动，表现出持续的呼吸振荡。明中暗孤子可以通过对明孤子进行相位压印而产生。在介质速度下，两个孤子之间的碰撞是准弹性的，数值模拟了偶极$^{164}$ Dy BEC的三维平均场Gross-Pitaevskii方程，利用实际的相互作用参数证明了结果.
We develop an analytical description of static ferrodark solitons, the $\mathbb{Z}_2$ topological defects in the magnetic order, in the easy-plane phase of ferromagnetic spin-1 Bose-Einstein condensates. We find that the type-I ferrodark soliton has a single width while the type-II ferrodark soliton exhibits two characteristic length scales. The proposed ansatzes show excellent agreement with numerical results. Spin-singlet amplitudes, nematic tensor densities and nematic currents of ferrodark solitons are also discussed. The $\mathbb{Z}_2$ topological defects in the mass superfluid order, dar…
We investigate non-degenerate bound state solitons systematically in multi-component Bose-Einstein condensates, through developing Darboux transformation method to derive exact soliton solutions analytically. In particular, we show that bright solitons with nodes correspond to the excited bound eigen-states in the self-induced effective quantum wells, in sharp contrast to the bright soliton and dark soliton reported before (which usually correspond to ground state and free eigen-state respectively). We further demonstrate that the bound state solitons with nodes are induced by incoherent inter…
The truncated Wigner and positive-P phase-space representations are used to study the dynamics of a one-dimensional Bose gas. This allows calculations of the breathing quantum dynamics of higher-order solitons with 10^{3}-10^{5} particles, as in realistic Bose-Einstein condensation (BEC) experiments. Although classically stable, these decay quantum mechanically. Our calculations show that there are large nonlocal correlations. These also violate the Cauchy-Schwarz inequality, showing the presence of nonclassical quantum entanglement.
我们证明了由于偶极排斥接触相互作用而在中心平面上形成的强、稳定、可移动的准一维暗中亮偶极玻色-爱因斯坦凝聚体（BEC）孤子.在中等速度下，两个这样的孤子碰撞的头被发现是几乎没有变形的准弹性。本文还讨论了在实验室中利用相位印记产生偶极明中暗孤子的方案。在偶极二元BEC中可以形成丰富多样的暗中亮孤子，可以是一个暗中亮孤子与一个亮孤子耦合，也可以是两个暗中亮孤子耦合。结果表明，使用数值模拟在三个空间维度采用现实的相互作用参数的偶极164 Dy BEC和二进制164 Dy-162 Dy BEC。
Stable and mobile two-dimensional dipolar ring-dark-in-bright Bose-Einstein condensate soliton
我们证明了一个强大的，稳定的，移动的二维（2D）偶极环暗中亮（RDB）玻色-爱因斯坦凝聚体（BEC）孤子的排斥接触相互作用，受到谐波陷阱沿$y$方向垂直于偏振方向$z$。这样的RDB孤子有一个环形缺口（密度为零）印在一个2D亮孤子自由移动在$x-z$平面。在中等速度下，两个这样的孤子的迎头碰撞被发现是准弹性的，几乎没有变形。论证了利用相位印记产生RDB孤子的可能性。结果表明，使用数值模拟采用现实的相互作用参数在偶极$^{164}$ Dy BEC。
We numerically study the breathing dynamics induced by collision between bright solitons in the one-dimensional Bose-Einstein condensates with strong dipole-dipole interaction. This breathing phenomenon is closely related to the after-collision short-lived attraction of solitons induced by the dipolar effect. The initial phase difference of solitons leads to the asymmetric dynamics after collision, which is manifested on their different breathing amplitude, breathing frequency, and atom number. We clarify that the asymmetry of breathing frequency is directly induced by the asymmetric atom numb…
Ultracold gases provide an unprecedented level of control for the investigation of soliton dynamics and collisions. We present a scheme for deterministically preparing pairs of three-component solitons in a Bose-Einstein condensate. Our method is based on local spin rotations which simultaneously imprint suitable phase and density distributions. This enables us to observe striking collisional properties of the vector degree of freedom which naturally arises for the coherent nature of the emerging multi-component solitons. We find that the solitonic properties in the quasi-one-dimensional syste…
We study general collisions between chiral solitons in Bose-Einstein condensates subject to combined attractive and current-dependent interatomic interactions. A simple analysis based on the linear superposition of the solitons allows us to determine the relevant time and space scales of the dynamics, which is illustrated by extensive numerical simulations. By varying the differential amplitude, the relative phase, the average velocity, and the relative velocity of the solitons, we characterize the different dynamical regimes that give rise to oscillatory and interference phenomena. Apart from…
Embedded solitons are rare self-localized nonlinear structures that, counterintuitively, survive inside a continuous background of resonant states. While this topic has been widely studied in nonlinear optics, it has received almost no attention in the field of Bose-Einstein condensation. In this work, we consider experimentally realizable Bose-Einstein condensates loaded in one-dimensional optical lattices and demonstrate that they support continuous families of stable three-dimensional (3D) embedded solitons. These solitons can exist inside the resonant continuous Bloch bands because they ar…
We model propagation of far-red-detuned optical vortex beams through a Bose-Einstein Condensate using nonlinear Schrödinger and Gross-Pitaevskii equations. We show the formation of coupled light/atomic solitons that rotate azimuthally before moving off tangentially, carrying angular momentum. The number, and velocity, of solitons, depends on the orbital angular momentum of the optical field. Using a Bessel-Gauss beam increases radial confinement so that solitons can rotate with fixed azimuthal velocity. Our model provides a highly controllable method of channelling a BEC and atomic transport.
