Trapped two-dimensional condensates with synthetic spin-orbit coupling

We study trapped 2D atomic Bose-Einstein condensates with spin-independent interactions in the presence of an isotropic spin-orbit coupling, showing that a rich physics results from the non-trivial interplay between spin-orbit coupling, confinement and inter-atomic interactions. For low interactions two types of half-vortex solutions with different winding occur, whereas strong-enough repulsive interactions result in a stripe-phase similar to that predicted for homogeneous condensates. Intermediate interaction regimes are characterized for large enough spin-orbit coupling by an hexagonally-symmetric phase with a triangular lattice of density minima similar to that observed in rapidly rotating condensates.Comment: 4 pages, 3 figures,reduced the resolution of figure 1 from previous submissio

Density engineering via inter-condensate dipole-dipole interactions: axial confinement and supersolids

Exploiting the long-range and anisotropic nature of dipole-dipole interactions, we show that the density of a {\em target} dipolar Bose-Einstein condensate can be engineered and axially confined using a trapped {\em control} dipolar condensate. Increasing the number of control condensates leads to exotic ground state structures, including supersolids and an incoherent array of density peaks. Single and double-peaked periodic structures are observed as a function of spacing between the control condensates. Our ideas may be generalized to engineer any other dipolar quantum system using another one of a similar dipole character. For instance, a Rydberg atom with electric dipole moment may be confined and manipulated using a trapped polar molecule and vice versa via long-range dipole-dipole interactions.Comment: 7 pages, 7 figure

Spontaneous Crystallization And Filamentation Of Solitons In Dipolar Condensates

Inter-site interactions play a crucial role in polar gases in optical lattices even in the absence of hopping. We show that due to these long-range interactions a destabilized stack of quasi-one dimensional Bose-Einstein condensates develops a correlated modulational instability in the non-overlapping sites. Interestingly, this density pattern may evolve spontaneously into soliton filaments or a crystal of solitons that can be so created for the first time in ultra-cold gases. These self-assembled structures may be observed under realistic conditions within current experimental feasibilities.Comment: 6 pages, 7 figure

Self-bound Doubly-Dipolar Bose-Einstein condensates

We analyze the physics of self-bound droplets in a doubly dipolar Bose-Einstein condensate (DDBEC) composed by particles with both electric and magnetic dipole moments. Using the particularly relevant case of dysprosium, we show that the anisotropy of the doubly-dipolar interaction potential is highly versatile and nontrivial, depending critically on the relative orientation and strength between the two dipole moments. This opens novel possibilities for exploring intriguing quantum many-body physics. Interestingly, by varying the angle between the two dipoles we find a dimensional crossover from quasi one-dimensional to quasi two-dimensional self-bound droplets. This opens a so far unique scenario in condensate physics, in which a dimensional crossover is solely driven by interactions in the absence of any confinement.Comment: 12 pages, 7 figure

Dynamical excitation of maxon and roton modes in a Rydberg-dressed Bose-Einstein condensate

We investigate the dynamics of a three-dimensional Bose-Einstein condensate of ultracold atomic gases with a soft-core shape long-range interaction, which is induced by laser dressing the atoms to a highly excited Rydberg state. For a homogeneous condensate, the long-range interaction drastically alters the dispersion relation of the excitation, supporting both roton and maxon modes. Rotons are typically responsible for the creation of supersolids, while maxons are normally dynamically unstable in BECs with dipolar interactions. We show that maxon modes in the Rydberg-dressed condensate, on the contrary, are dynamically stable. We find that the maxon modes can be excited through an interaction quench, i.e. turning on the soft-core interaction instantaneously. The emergence of the maxon modes is accompanied by oscillations at high frequencies in the quantum depletion, while rotons lead to much slower oscillations. The dynamically stable excitation of the roton and maxon modes leads to persistent oscillations in the quantum depletion. Through a self-consistent Bogoliubov approach, we identify the dependence of the maxon mode on the soft-core interaction. Our study shows that maxon and roton modes can be excited dynamically and simultaneously by quenching Rydberg-dressed long-range interactions. This is relevant to current studies in creating and probing exotic states of matter with ultracold atomic gases