This paper reviews the recent theoretical and experimental advances in study of ultra-cold gases made bosonic particles interacting via long-range, anisotropic dipole–dipole interaction, addition to short-range isotropic contact interaction usually at work gases. The specific properties emerging from dipolar are emphasized, mean-field regime valid for dilute Bose–Einstein condensates, strongly correlated regimes reached bosons optical lattices.

We study the expansion of a dilute ultracold sample fermions initially trapped in an anisotropic harmonic trap. The cloud provides valuable information about state system and role interactions. In particular, time evolution deformation expanding behaves quite differently depending on whether is normal or superfluid phase. For phase, we predict inversion sample, similar to what happens with Bose-Einstein condensates. Vice versa, aspect ratio never achieved, if mean field interaction...

This tutorial is a theoretical work, in which we study the physics of ultra-cold dipolar bosonic gases optical lattices.Such consist atoms or molecules that interact via forces, and are cooled below quantum degeneracy temperature, typically nK range.When such degenerate gas loaded into an lattice produced by standing waves laser light, new kinds physical phenomena occur.These systems realize then extended Hubbard-type models, can be brought to strongly correlated regime.The properties gases,...

We investigate the physics of dipolar bosons in a two dimensional optical lattice. It is known that due to long-range character dipole-dipole interaction, ground state phase diagram gas an lattice presents novel quantum phases, like checkerboard and supersolid phases. In this paper, we consider properties system beyond its state, finding it characterised by multitude almost degenerate metastable states, often competing with state. This makes similar disordered opens possibilities using them...

We consider two interacting bosons in a dimerized Su-Schrieffer-Heeger (SSH) lattice. identify rich variety of two-body states. In particular, for open boundary conditions and moderate interactions, edge bound states (EBS) are present even the dimerization that does not sustain single-particle Moreover, large values we find breaking standard bulk-boundary correspondence. Based on mapping particles one dimension onto single particle dimensions, propose an experimentally realistic coupled...

The competition between tunneling and interactions in bosonic lattice models generates a whole variety of different quantum phases. While, the presence single species interacting via on site interaction, phase diagram presents only superfluid or Mott insulating phases, for long-range multiple species, exotic phases such as supersolid pair-superfluid appear. In this Letter, we show first time that coexistence effective leads to formation novel pair-supersolid phase, namely, composites. We...

We calculate the single-particle spectral function for one-band Bose-Hubbard model within random-phase approximation (RPA). In strongly correlated superfluid, in addition to gapless phonon excitations, we find extra gapped modes, which become particularly relevant near superfluid-Mott quantum phase transition (QPT). The strength one of a precursor Mott phase, grows as QPT is approached and evolves into hole (particle) excitation insulator depending on whether chemical potential...

We study the dynamic process of splitting a condensate by raising potential barrier in center harmonic trap. use two-mode model to describe phase coherence between two halves condensate. Furthermore, we explicitly consider spatial dependence mode funtions, which varies depending on barrier. This allows us get tunneling coupling wells and on-site energy as function height. Moreover, can some insight into collective modes that are excited internal external degrees freedom variational ansatz....

Ultra‐cold atomic systems provide a new setting where to investigate the role of long‐range interactions. In this paper we will review basics features those physical systems, in particular focusing on case Chromium atoms. On experimental side, report observation dipolar effects expansion dynamics Bose‐Einstein condensate. By using Feshbach resonance, scattering length characterising contact interaction can be strongly reduced, thus increasing relative effect dipole‐dipole interaction. Such...

We study the physics of a mobile impurity confined in two-dimensional lattice, moving within Bose-Hubbard bath at zero temperature. Exploiting quantum Gutzwiller formalism, we develop beyond-Fröhlich model bath-impurity interaction to describe properties polaronic quasiparticle formed by dressing fluctuations bath. find stable and well-defined polaron throughout entire phase diagram bath, except for very low tunneling limit hard-core superfluid. The are highly sensitive different...

We study the physics of ultracold dipolar bosons in optical lattices. show that dipole-dipole interactions lead to appearance many insulating metastable states. stability and lifetime these states using a generalization instanton theory. also investigate possibilities prepare, control, manipulate time-dependent superlattice modifications modulations. transfer from one configuration another necessarily occurs via superfluid states, but can be controlled fully at quantum level. how created...

We study the effect of a one-dimensional periodic potential on dynamic structure factor an interacting Bose-Einstein condensate at zero temperature. show that, due to phononic correlations, excitation strength toward first band develops typical oscillating behavior as function momentum transfer, and vanishes even multiples Bragg momentum. The effects interactions static are found be significantly amplified by presence optical potential. Our predictions can tested in stimulated photon...

The absence of energy dissipation leads to an intriguing out-of-equilibrium dynamics for ultracold polar gases in optical lattices, characterized by the formation dynamically-bound on-site and inter-site clusters two or more particles, effective blockade repulsion. These effects combined with controlled preparation initial states available cold experiments can be employed create interesting states. include quasi-equilibrated effectively repulsive 1D attractive dipolar interactions crystals....

We investigate the superfluid properties of a Bose–Einstein condensate (BEC) trapped in one-dimensional periodic potential. study, both analytically (in tight binding limit) and numerically, Bloch chemical potential, energy Bogoliubov dispersion relation, we introduce two different, density dependent, effective masses group velocities. The spectrum predicts existence sound waves, arising energetic dynamical instabilities at critical values BEC quasi-momentum which dramatically affect its...

We show that fermionic atoms have crucial advantages over bosonic in terms of loading optical lattices for use as a possible quantum computation device. After analyzing the change level structure non-uniform confining potential periodic is superimposed to it, we how this combined with Pauli principle and fermion degeneracy can be exploited create unit occupancy lattice sites very high efficiency.

We propose a general procedure for reducing the three-dimensional Schrodinger equation atoms moving along strongly confining atomic waveguide to an effective one-dimensional equation. This is applied case of rotating closed-loop waveguide. The possibility including mean-field interactions presented. Application theory characterize new concept based on optical tweezers finally discussed.

We study the role of dipolar-induced resonance (DIR) in a quasi-one-dimensional system ultracold bosons. first describe effect DIR on two particles harmonic trap. Then, we consider deep optical lattice loaded with dipolar In order to this system, introduce novel atom-dimer extended Bose-Hubbard model, which is minimal model correctly accounting for DIR. analyze impact phase diagram at $T=0$ by exact diagonalization small-sized system. show that strongly affects diagram. particular, predict...

We consider a mixture of two bosonic species with tunable interspecies interaction in periodic potential and discuss the advantages low filling factors on detection pair-superfluid phase. show how emergence such phase can be put dramatically into evidence by looking at interference pictures density correlations after expansion changing from attractive to repulsive.

We study the propagation of sound waves in a Bose-Einstein condensate trapped one-dimensional optical lattice. find that velocity wavepackets decreases with increasing lattice depth, as predicted by Bogoliubov theory. The strong interplay between nonlinearities and periodicity external potential raise new phenomena which are not present uniform case. Shock waves, for instance, can propagate slower than due to negative curvature dispersion relation. Moreover, nonlinear corrections theory...

We use Bogoliubov theory to calculate the beyond mean field correction equation of state a weakly interacting Bose gas in presence tight 2D optical lattice. show that lattice induces characteristic 3D 1D crossover behavior quantum fluctuations. Using hydrodynamic superfluids, we corresponding shift collective frequencies harmonically trapped gas. find this can be order few percent and hence easily measurable current experiments. The depletion condensate is also discussed.

We study the low-energy excitations of Bose-Hubbard model in strongly-interacting superfluid phase using a Gutzwiller approach and extract single-particle single-hole excitation amplitudes for each mode. report emergent mode-dependent particle-hole symmetry on specific arc-shaped lines diagram connecting well-known Lorentz-invariant limits model. By tracking in-phase symmetric oscillations order parameter, we provide an answer to long-standing question about fate pure amplitude Higgs mode...

We investigate the quantum state of burst atoms seen in recent Rb-85 experiments at JILA. show that presence a resonance scattering can lead to pairing instability generating an outflow with energy comparable observed. A effective field theory is used study this dynamical process inhomogeneous system spherical symmetry.