We report the observation of coexisting Bose-Einstein condensate (BEC) and Fermi gas in a magnetic trap. With very small fraction thermal atoms, 7Li is quasipure contact with 6Li gas. The lowest common temperature 0.28 microK approximately 0.2(1)T(C) = 0.2(1)T(F) where T(C) BEC critical T(F) temperature. has one-dimensional character.

We report Bose-Einstein condensation of weakly bound 6Li2 molecules in a crossed optical trap near Feshbach resonance. measure molecule-molecule scattering length 170(+100)(-60) nm at 770 G, good agreement with theory. study the 2D expansion cloud and show deviation from hydrodynamic behavior BEC-BCS crossover region.

We create weakly bound Li2 molecules from a degenerate two component Fermi gas by sweeping magnetic field across Feshbach resonance. The atom-molecule transfer efficiency can reach 85% and is studied as function of initial temperature. bosonic remain trapped for 0.5 s their temperature within factor 2 the Bose-Einstein condensation A thermodynamical model reproduces qualitatively experimental findings.

We report on the production of $^{39}\mathrm{K}$ matter-wave bright solitons, i.e., one-dimensional matter waves that propagate without dispersion thanks to attractive interactions. The volume soliton is studied as a function scattering length through three-body losses, revealing peak densities high $\ensuremath{\sim}5\ifmmode\times\else\texttimes\fi{}{10}^{20}\phantom{\rule{0.16em}{0ex}}{\mathrm{m}}^{\ensuremath{-}3}$. Our close collapse threshold, are strongly bound and will find...

We study the horizontal expansion of vertically confined ultra-cold atoms in presence disorder. Vertical confinement allows us to realize a situation with few coupled harmonic oscillator quantum states. The disordered potential is created by an optical speckle at angle 30{\deg} respect plane, resulting effective anisotropy correlation lengths factor 2 that plane. observe diffusion leading non-Gaussian density profiles. Diffusion coefficients, extracted from experimental results, show and...

The existence of quantum droplets in binary Bose-Einstein condensate mixtures relies on beyond-mean-field effects, competing with mean-field effects. Interestingly, the effects change from repulsive three dimensions (3D) to attractive 1D leading drastically different behaviors. We quantitatively model crossover 3D relevant case an elongated harmonic trap and give realistic numbers for experimental realizations. identify quantify two main limiting factors: three-body losses tiny energy...

We propose and demonstrate the appearance of an effective attractive three-body interaction in coherently driven two-component Bose-Einstein condensates. It originates from spinor degree freedom that is affected by a two-body mean-field shift transition frequency. Importantly, its strength can be controlled with Rabi-coupling it does not come additional losses. In experiment, interactions are adjusted to play predominant role equation state cigar-shaped trapped condensate. This confirmed...

We report the all-optical production of Bose-Einstein condensates (BEC) $^{39}\mathrm{K}$ atoms. directly load $3\ifmmode\times\else\texttimes\fi{}{10}^{7}$ atoms in a large volume optical dipole trap from gray molasses on D1 transition. then apply small magnetic quadrupole field to polarize sample before transferring tightly confining trap. Evaporative cooling is finally performed close Feshbach resonance enhance scattering length. Our setup allows one cross BEC threshold with...

We numerically study the dynamics of cold atoms in a two-dimensional disordered potential. consider an anisotropic speckle potential and focus on classical regime, which is relevant to some recent experiments. First, we behavior particles with fixed energy identify different transport regimes. For low energy, are classically localized due absence percolating cluster. high undergo normal diffusion show that constants scale algebraically particle anisotropy factor significantly differs from...

We theoretically calculate and experimentally measure the beyond-mean-field (BMF) equation of state in a coherently coupled two-component Bose-Einstein condensate (BEC) regime where averaging interspecies intraspecies coupling constants over hyperfine composition single-particle dressed predicts exact cancellation two-body interaction. show that with increasing Rabi-coupling frequency Ω, BMF energy density crosses from nonanalytic Lee-Huang-Yang scaling ∝n^{5/2} to an expansion integer...

We observe the build-up of a matter wave interference pattern from single atom detection events in double-slit experiment. The arises two overlapping laser beams extracted Rubidium Bose-Einstein condensate. Our detector is high-finesse optical cavity which realizes quantum measurement presence an and thereby projects delocalized atoms into state with zero or one resonator. experiment reveals simultaneously granular nature matter.

We observe nonlinear scattering of 39K atomic bright solitons launched in a one-dimensional (1D) speckle disorder. directly compare it with the non-interacting particles same The atoms soliton tend to be collectively either reflected or transmitted, contrast behavior independent singlescattering regime, thus demonstrating clear effect scattering. observed strong fluctuations fraction, between zero and 100%, are interpreted as consequence sensitivity system experimental conditions particular...

We realize textbook experiments on Bose-Einstein condensate tunneling through thin repulsive potential barriers. In particular, we demonstrate atom though a single optical barrier in the quantum scattering regime where de Broglie wavelength of atoms is larger than width. Such beam splitter can be used for interferometry and study case two barriers creating an atomic Fabry-P\'erot cavity. Technically, velocity spread reduced due to use $^{39}\mathrm{K}$ with no interactions. The are created...

Time-of-flight experiments with quantum gases reveal the momentum distribution under assumption of a ballistic expansion. The authors investigate validity at level single particles, thanks to detection individual metastable Helium atoms. They measure number two-body collisions occuring during time flight and provide quantitative estimate role when atoms are released from lattice potential

In a one-dimensional (1D) disordered potential, quantum interferences leading to Anderson lo-calization are ubiquitous, such that all wave-functions exponentially localized. Moreover, no phase transition toward delocalization is expected in 1D. This behavior strongly modified the presence of bias force. We experimentally study this case, launching non-interacting 39 K Bose-Einstein condensate 1D potential induced by far-off-resonance laser speckle, while controlling agreement with...

We study superfluid transitions in bidimensional (2D) and tridimensional (3D) disordered interacting Bose gases. work the limit of long-range correlated disorder such that it can be treated local density approximation. present transition curves both disorder-temperature plane disorder-entropy 2D 3D Surprisingly, we find a small amount is always favorable to apparition superfluid. Our results offer quantitative comparison with recent experiments ultracold gases, for which no exact theory exists.

We study atom losses associated to a previously unreported magnetic Feshbach resonance in $^{39}\mathrm{K}$. This is peculiar that it presents $d$-wave character both the open and closed channels, directly coupled by dominant spin-exchange interaction. The open-channel present specific signatures such as strong temperature dependance anisotropic line shapes. strength position depend on axial projection of orbital angular momentum system are extracted from rigorous multichannel calculations....

We report on the production of 39 K matter-wave bright solitons, i.e., 1D matter-waves that propagate without dispersion thanks to attractive interactions. The volume soliton is studied as a function scattering length through three-body losses, revealing peak densities high $\sim 5 \times 10^{20} m^{-3}$. Our close collapse threshold, are strongly bound and will find applications in fundamental physics atom interferometry.

We report on experiments in 6Li Fermi gases near Feshbach resonances. A broad s‐wave resonance is used to form a Bose‐Einstein condensate of weakly bound 6Li2 molecules crossed optical trap. The measured molecule‐molecule scattering length 170−60+100 nm at 770 G found good agreement with theory. expansion energy the cloud BEC‐BCS crossover region measured. Finally we discuss properties p‐wave resonances observed 200 Gauss and new heteronuclear 6Li‐ 7Li mixture.

We numerically analyze spectral properties of the Fibonacci model which is a one-dimensional quasiperiodic system. find that energy levels this have distribution band widths $w$ obeys $P_B(w)\sim w^{\alpha}$ $(w\to 0)$ and $P_B(w) \sim e^{-\beta w}$ $(w\to\infty)$, gap $P_G(s)\sim s^{-\delta}$ $(s\to ($\alpha,\beta,\delta >0$) . also compare results with those multi-scale Cantor sets. qualitative differences between spectra