



01486nas a2200181   4500008004100000245004800041210004800089260001500137300001100152490000700163520100000170100001801170700002101188700002301209700001901232700001701251856003601268       2016                        eng d00aPhotoassociation of spin polarized Chromium0 aPhotoassociation of spin polarized Chromium  c2016/02/29  a0214060 v933 aWe report the homonuclear photoassociation (PA) of ultracold 52Cr atoms in an optical dipole trap. This constitutes the first measurement of PA in an element with total electron spin S~>1. Although Cr, with its 7S3 ground and 7P4,3,2 excited states, is expected to have a complicated PA spectrum we show that a spin polarized cloud exhibits a remarkably simple PA spectrum when circularly polarized light is applied. Over a scan range of 20 GHz below the 7P3 asymptote we observe two distinct vibrational series each following a LeRoy-Bernstein law for a C3/R3 potential with excellent agreement. We determine the C3 coefficients of the Hund's case c) relativistic adiabatic potentials to be -1.83±0.02 a.u. and -1.46±0.01a.u.. Theoretical non-rotating Movre-Pichler calculations enable a first assignment of the series to Ω=6u and 5g potential energy curves. In a different set of experiments we disturb the selection rules by a transverse magnetic field which leads to additional PA series.1 aRührig, Jahn1 aBäuerle, Tobias1 aJulienne, Paul, S.1 aTiesinga, Eite1 aPfau, Tilman  uhttp://arxiv.org/abs/1512.0437801850nas a2200205   4500008004100000245008200041210006900123260001500192490000700207520120600214100002601420700002601446700002301472700002701495700002701522700001701549700002101566700002001587856003701607       2014                        eng d00aQuantum correlations and entanglement in far-from-equilibrium spin  systems
0 aQuantum correlations and entanglement in farfromequilibrium spin  c2014/12/150 v903 a  By applying complementary analytic and numerical methods, we investigate the
dynamics of spin-$1/2$ XXZ models with variable-range interactions in arbitrary
dimensions. The dynamics we consider is initiated from uncorrelated states that
are easily prepared in experiments, and can be equivalently viewed as either
Ramsey spectroscopy or a quantum quench. Our primary focus is the dynamical
emergence of correlations and entanglement in these far-from-equilibrium
interacting quantum systems: we characterize these correlations by the
entanglement entropy, concurrence, and squeezing, which are inequivalent
measures of entanglement corresponding to different quantum resources. In one
spatial dimension, we show that the time evolution of correlation functions
manifests a non-perturbative dynamic singularity. This singularity is
characterized by a universal power-law exponent that is insensitive to small
perturbations. Explicit realizations of these models in current experiments
using polar molecules, trapped ions, Rydberg atoms, magnetic atoms, and
alkaline-earth and alkali atoms in optical lattices, along with the relative
merits and limitations of these different systems, are discussed.
1 aHazzard, Kaden, R. A.1 avan den Worm, Mauritz1 aFoss-Feig, Michael1 aManmana, Salvatore, R.1 aTorre, Emanuele, Dalla1 aPfau, Tilman1 aKastner, Michael1 aRey, Ana, Maria  uhttp://arxiv.org/abs/1406.0937v1