Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userProperties of a nematic spin vortex in an antiferromagnetic spin-1 Bose-Einstein condensate
75
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
A spin-1 condensate with antiferromagnetic interactions supports nematic spin vortices in the easy-plane polar phase. These vortices have a $2pi$ winding of the nematic director, with a core structure that depends on the quadratic Zeeman energy. We characterize the properties of the nematic spin vortex in a uniform quasi-two-dimensional system. We also obtain the vortex excitation spectrum and use it to quantify its stability against dissociating into two half-quantum vortices, finding a parameter regime where the nematic spin vortex is dynamically stable. These results are supported by full dynamical simulations.
rate research
Read More
We find a novel topological defect in a spin-nematic superfluid theoretically. A quantized vortex spontaneously breaks its axisymmetry, leading to an elliptic vortex in nematic-spin Bose-Einstein condensates with small positive quadratic Zeeman effect. The new vortex is considered the Joukowski transform of a conventional vortex. Its oblateness grows when the Zeeman length exceeds the spin healing length. This structure is sustained by balancing the hydrodynamic potential and the elasticity of a soliton connecting two spin spots, which are observable by in situ magnetization imaging. The theoretical analysis clearly defines the difference between half quantum vortices of the polar and antiferromagnetic phases in spin-1 condensates.
We propose a generalized Mathieu equation (GME) which describes well the dynamics for two different models in spin-1 Bose-Einstein condensates. The stability chart of this GME differs significantly from that of Mathieus equation and the unstable dynamics under this GME is called generalized parametric resonance. A typical region of $epsilon gtrsim 1$ and $delta approx 0.25$ can be used to distinguish these two equations. The GME we propose not only explains the experimental results of Hoang et al. [Nat. Commun. 7, 11233 (2016)] in nematic space with a small driving strength, but predicts the behavior in the regime of large driving strength. In addition, the model in spin space we propose, whose dynamics also obeys this GME, can be well-tuned such that it is easily implemented in experiments.
One of the excitements generated by the cold atom systems is the possibility to realize, and explore, varied topological phases stemming from multi-component nature of the condensate. Popular examples are the antiferromagnetic (AFM) and the ferromagnetic (FM) phases in the three-component atomic condensate with effective spin-1, to which different topological manifolds can be assigned. It follows, from consideration of homotopy, that different sorts of topological defects will be stable in each manifold. For instance, Skyrmionic texture is believed to be a stable topological object in two-dimensional AFM spin-1 condensate. Countering such common perceptions, here we show on the basis of a new wave function decomposition scheme that there is no physical parameter regime wherein the temporal dynamics of spin-1 condensate can be described solely within AFM or FM manifold. Initial state of definite topological number prepared entirely within one particular phase must immediately evolve into a mixed state. Accordingly, the very notion of topology and topological stability within the sub-manifold of AFM or FM become invalid. Numerical simulation reveals the linear Zeeman effect to be an efficient catalyst to extract the alternate component from an initial topological object prepared entirely within one particular sub-manifold, serving as a potential new tool for topology engineering in multi-component Bose-Einstein condensates.
We present Open
We theoretically show that the topology of a non-simply-connected annular atomic Bose-Einstein condensate enforces the inner surface waves to be always excited with outer surface excitations and that the inner surface modes are associated with induced vortex dipoles unlike the surface waves of a simply-connected one with vortex monopoles. Consequently, under stirring to drive an inner surface wave, a peculiar population oscillation between the inner and outer surface is generated regardless of annulus thickness. Moreover, a new vortex nucleation process by stirring is observed that can merge the inner vortex dipoles and outer vortex into a single vortex inside the annulus. The energy spectrum for a rotating annular condensate with a vortex at the center also reveals the distinct connection of the Tkachenko modes of a vortex lattice to its inner surface excitations.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
