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Long-term experimental carcinogenicity bioassay was carried out on MS 4A and MS 5A zeolites. The materials were tested on Sprague-Dawley rats by intraperitoneal, intrapleural, and subcutaneous injection of 25 mg in 1 ml of H2O. The results of this bioassay (the onset of one peritoneal mesothelioma in a male rat treated by intraperitoneal injection of zeolite MS 4A) calls for further and more sophisticated tests on zeolites used as detergents.

By means of time-dependent density-matrix renormalization-group (TDMRG) we are able to follow the real-time dynamics of a single impurity embedded in a one-dimensional bath of interacting bosons. We focus on the impurity breathing mode, which is found to be well-described by a single oscillation frequency and a damping rate. If the impurity is very weakly coupled to the bath, a Luttinger-liquid description is valid and the impurity suffers an Abraham-Lorentz radiation-reaction friction. For a large portion of the explored parameter space, the TDMRG results fall well beyond the Luttinger-liquid paradigm., Comment: 10 pages, 7 figures, main text and supplementary material merged in a single PRB style document

We present a novel optical cooling scheme that relies on hyperfine dark states to enhance loading and cooling atoms inside deep optical dipole traps. We demonstrate a seven-fold increase in the number of atoms loaded in the conservative potential with strongly shifted excited states. In addition, we use the energy selective dark-state to efficiently cool the atoms trapped inside the conservative potential rapidly and without losses. Our findings open the door to optically assisted cooling of trapped atoms and molecules which lack the closed cycling transitions normally needed to achieve low temperatures and the high initial densities required for evaporative cooling., Comment: 5 pages, 5 figures + supplemental material 2 pages

In search of non-classical correlations between momentum components of a Bose-Einstein condensate (BEC), we have investigated atom interferometers of trapped and free-falling BEC, obtaining a quantitative description of the spacing of interference fringes observed at output ports.

We report on the formation of heteronuclear quantum droplets in an attractive bosonic mixture of 41K and 87Rb. We observe long-lived self-bound states, both in free space and in an optical waveguide. In the latter case, the dynamics under the effect of a species-dependent force confirms their bound nature. By tuning the interactions from the weakly to the strongly attractive regime, we study the transition from expanding to localized states, in both geometries. We compare the experimental results with beyond mean-field theory and we find a good agreement in the full range of explored interactions. Our findings open up the production of long-lived droplets with important implications for further research., Comment: 9 pages, 7 figures

We report on the direct observation of the electromagnetically induced transparency (EIT) lineshape of cold Rb-87 atoms above and below the transition temperature for Bose-Einstein condensation (BEC). Similar results are observed in both temperature regimes, with an absorption reduction of about 60%. Good agreement with a theoretical model is discussed. (C) 2002 Elsevier Science B.V. All rights reserved.

Collective excitations have been observed in a Rb-87 Bose condensate, confined in a magneto-static, elongated, harmonic trap. We have measured the frequency of two different modes with zero angular momentum along the symmetry axis of the trap. Both the frequencies are in good agreement with the values predicted by the hydrodynamic theory of superfluids holding in the Thomas-Fermi regime.

We experimentally investigate the mix-dimensional scattering occurring when the collisional partners live in different dimensions. We employ a binary mixture of ultracold atoms and exploit a species-selective 1D optical lattice to confine only one atomic species in 2D. By applying an external magnetic field in proximity of a Feshbach resonance, we adjust the free-space scattering length to observe a series of resonances in mixed dimensions. By monitoring 3-body inelastic losses, we measure the magnetic field values corresponding to the mix-dimensional scattering resonances and find a good agreement with the theoretical predictions based on simple energy considerations., 5 pages, 4 figures, to be published in PRL

We report on the creation of heterospecies bosonic molecules, associated from an ultracold Bose-Bose mixture of 41K and 87Rb, by using a resonantly modulated magnetic field close to two Feshbach resonances. We measure the binding energy of the weakly bound molecular states versus the Feshbach field and compare our results to theoretical predictions. We observe the broadening and asymmetry of the association spectrum due to thermal distribution of the atoms, and a frequency shift occurring when the binding energy depends nonlinearly on the Feshbach field. A simple model is developed to quantitatively describe the association process. Our work marks an important step forward in the experimental route towards Bose-Einstein condensates of dipolar molecules., 5 pages, 4 figures

Ultracold atomic gases seem uniquely suited to experimentally realize and investigate physics long studied in the domain of condensed matter and solid state, with the distinct advantage that specific effects are better isolated from unnecessary complications often present in condensed samples. The paradigmatic superfluid to Mott insulator transition of a condensate in an optical lattice [1] confirmed the predictions of the Bose-Hubbard model [2,3], originally introduced to describe superfluid helium. With two species, the zero-temperature diagram of quantum phases is much richer than the simple duplication of the single species’ [4]. Indeed, it has been proposed that two species obeying an extended Bose-Hubbard model can mimic the physics of lattice spins described by the Heisenberg model [5,6] and give rise to yet unobserved quantum phases, like the double Mott insulator and the supercounterflow regime [7], with peculiar transport properties. Therefore, a double species condensate in an optical lattice stands as a promising candidate system for quantum simulations. Recently, the investigation of the two-species Bose-Hubbard was started from the regime where one species exhibits the loss of phase coherence usually associated with the Mott insulator transition, while the other is completely delocalized [8]. Already at this stage, the presence of two species leads to a surprising shift of the critical point, which is now the object of intense theoretical work [9].

We produce a heteronuclear quantum degenerate mixture of two bosonic species, $^{87}$Rb and $^{41}$K, in a three-dimensional optical lattice. On raising the lattice barriers, we observe the disapperance of the inference pattern of the heavier $^{87}$Rb, shifting toward shallower lattice depths in the presence of a minor fraction of $^{41}$K. This effect is sizable and requires only a marginal overlap between the two species. We compare our results with similar findings reported for Fermi-Bose mixtures and discuss the interpretation scenarios proposed to date, arguing that the explanation may be linked to the increased effective mass due to the interspecies interactions., 5 pages, 4 figures

We report on an experimental realization of a two-dimensional magneto-optical trap (2D-MOT) that allows the generation of cold atomic beams of 39K and 41K bosonic potassium isotopes. The high measured fluxes up to 1.0x10^11 atoms/s and low atomic velocities around 33 m/s are well suited for a fast and reliable 3D-MOT loading, a basilar feature for new generation experiments on Bose-Einstein condensation of dilute atomic samples. We also present a simple multilevel theoretical model for the calculation of the light-induced force acting on an atom moving in a MOT. The model gives a good agreement between predicted and measured flux and velocity values for our 2D-MOT., Comment: Updated references, 1 figure added, 10 pages, 9 figures

We have performed time-domain interferometry experiments with matter waves trapped in an harmonic potential above and below the Bose-Einstein phase transition. We interrogate the atoms according to the method of separated oscillating fields, with a sequence of two radio-frequency pulses, separated by a time delay T. We observe the oscillation of the population between two internal Zeeman states, as a function of the delay T. We find a strong depletion of the interference fringes for both the Bose condensates and the thermal clouds above condensation, even at very short times, when the clouds are still overlapping. Actually, we explain the observed loss of contrast in terms of phase patterns imprinted by the relative motion, as a consequence of the entanglement between the internal and external states of the trapped atoms., 4 pages, 3 figures

A simple model that enables to calculate the effects of dipole and radiation-pressure forces on the spectroscopic determination of energy separations was developed. The resulting model provides the means for recovering the redshift as well as for explaining a blueshift of the Lamb dipole line center for a closed transition in a beam of 4He atoms.