Search results for "Bose-Einstein condensates"
showing 6 items of 6 documents
Counterdiabatic vortex pump in spinor Bose-Einstein condensates
2017
Topological phase imprinting is a well-established technique for deterministic vortex creation in spinor Bose-Einstein condensates of alkali metal atoms. It was recently shown that counter-diabatic quantum control may accelerate vortex creation in comparison to the standard adiabatic protocol and suppress the atom loss due to nonadiabatic transitions. Here we apply this technique, assisted by an optical plug, for vortex pumping to theoretically show that sequential phase imprinting up to 20 cycles generates a vortex with a very large winding number. Our method significantly increases the fidelity of the pump for rapid pumping compared to the case without the counter-diabatic control, leadin…
Synthetic electromagnetic knot in a three-dimensional skyrmion
2018
We experimentally simulate a quantum-mechanical particle interacting with knotted electromagnetic fields.
Control of photoassociation of atomic Bose-Einstein condensates by laser field configuration
2016
In this work we show that it is to perform an efficient adiabatic passage in a basic quadratic-nonlinear quantum two-state system describing weakly bound molecule formation in atomic Bose-Einstein condensates through photoassociation by laser fields. An efficient adiabatic transfer is also possible if the third-order nonlinearities describing the atom-atom, atom-molecule, and molecule-molecule elastic scattering are taken into account. The transfer is achieved by choosing a proper detuning derived by solving the inverse problem.We also show that one can perform a stimulated Raman exact tracking in a quadratic-nonlinear quantum three-state system.The irreversible losses from the intermediate…
Attractive versus repulsive interactions in the Bose-Einstein condensation dynamics of relativistic field theories
2017
We study the impact of attractive self-interactions on the nonequilibrium dynamics of relativistic quantum fields with large occupancies at low momenta. Our primary focus is on Bose-Einstein condensation and nonthermal fixed points in such systems. As a model system we consider O(N)-symmetric scalar field theories. We use classical-statistical real-time simulations, as well as a systematic 1/N expansion of the quantum (2PI) effective action to next-to-leading order. When the mean self-interactions are repulsive, condensation occurs as a consequence of a universal inverse particle cascade to the zero-momentum mode with self-similar scaling behavior. For attractive mean self-interactions the …
Stabilization of 1D solitons by fractional derivatives in systems with quintic nonlinearity
2022
AbstractWe study theoretically the properties of a soliton solution of the fractional Schrödinger equation with quintic nonlinearity. Under “fractional” we understand the Schrödinger equation, where ordinary Laplacian (second spatial derivative in 1D) is substituted by its fractional counterpart with Lévy index $$\alpha$$ α . We speculate that the latter substitution corresponds to phenomenological account for disorder in a system. Using analytical (variational and perturbative) and numerical arguments, we have shown that while in the case of Schrödinger equation with the ordinary Laplacian (corresponding to Lévy index $$\alpha =2$$ α = 2 ), the soliton is unstable, even infinitesimal diffe…
Three-dimensional splitting dynamics of giant vortices in Bose-Einstein condensates
2018
We study the splitting dynamics of giant vortices in dilute Bose-Einstein condensates by numerically integrating the three-dimensional Gross-Pitaevskii equation in time. By taking advantage of tetrahedral tiling in the spatial discretization, we decrease the error and increase the reliability of the numerical method. An extensive survey of vortex splitting symmetries is presented for different aspect ratios of the harmonic trapping potential. The symmetries of the splitting patterns observed in the simulated dynamics are found to be in good agreement with predictions obtained by solving the dominant dynamical instabilities from the corresponding Bogoliubov equations. Furthermore, we observe…