%0 Journal Article
%J Physical Review A
%D 2014
%T Quantum correlations and entanglement in far-from-equilibrium spin systems
%A Kaden R. A. Hazzard
%A Mauritz van den Worm
%A Michael Foss-Feig
%A Salvatore R. Manmana
%A Emanuele Dalla Torre
%A Tilman Pfau
%A Michael Kastner
%A Ana Maria Rey
%X 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.
%B Physical Review A
%V 90
%8 2014/12/15
%G eng
%U http://arxiv.org/abs/1406.0937v1
%N 6
%! Phys. Rev. A
%R 10.1103/PhysRevA.90.063622
%0 Journal Article
%J Physical Review Letters
%D 2013
%T Far from equilibrium quantum magnetism with ultracold polar molecules
%A Kaden R. A. Hazzard
%A Salvatore R. Manmana
%A Michael Foss-Feig
%A Ana Maria Rey
%X Recent theory has indicated how to emulate tunable models of quantum magnetism with ultracold polar molecules. Here we show that present molecule optical lattice experiments can accomplish three crucial goals for quantum emulation, despite currently being well below unit filling and not quantum degenerate. The first is to verify and benchmark the models proposed to describe these systems. The second is to prepare correlated and possibly useful states in well-understood regimes. The third is to explore many-body physics inaccessible to existing theoretical techniques. Our proposal relies on a non-equilibrium protocol that can be viewed either as Ramsey spectroscopy or an interaction quench. It uses only routine experimental tools available in any ultracold molecule experiment.
%B Physical Review Letters
%V 110
%8 2013/2/11
%G eng
%U http://arxiv.org/abs/1209.4076v1
%N 7
%! Phys. Rev. Lett.
%R 10.1103/PhysRevLett.110.075301
%0 Journal Article
%J Physical Review B
%D 2013
%T Topological phases in ultracold polar-molecule quantum magnets
%A Salvatore R. Manmana
%A E. M. Stoudenmire
%A Kaden R. A. Hazzard
%A Ana Maria Rey
%A Alexey V. Gorshkov
%X We show how to use polar molecules in an optical lattice to engineer quantum spin models with arbitrary spin S >= 1/2 and with interactions featuring a direction-dependent spin anisotropy. This is achieved by encoding the effective spin degrees of freedom in microwave-dressed rotational states of the molecules and by coupling the spins through dipolar interactions. We demonstrate how one of the experimentally most accessible anisotropies stabilizes symmetry protected topological phases in spin ladders. Using the numerically exact density matrix renormalization group method, we find that these interacting phases -- previously studied only in the nearest-neighbor case -- survive in the presence of long-range dipolar interactions. We also show how to use our approach to realize the bilinear-biquadratic spin-1 and the Kitaev honeycomb models. Experimental detection schemes and imperfections are discussed.
%B Physical Review B
%V 87
%8 2013/2/26
%G eng
%U http://arxiv.org/abs/1210.5518v2
%N 8
%! Phys. Rev. B
%R 10.1103/PhysRevB.87.081106
%0 Journal Article
%J Physical Review A
%D 2011
%T Quantum Magnetism with Polar Alkali Dimers
%A Alexey V. Gorshkov
%A Salvatore R. Manmana
%A Gang Chen
%A Eugene Demler
%A Mikhail D. Lukin
%A Ana Maria Rey
%X We show that dipolar interactions between ultracold polar alkali dimers in optical lattices can be used to realize a highly tunable generalization of the t-J model, which we refer to as the t-J-V-W model. The model features long-range spin-spin interactions J_z and J_perp of XXZ type, long-range density-density interaction V, and long-range density-spin interaction W, all of which can be controlled in both magnitude and sign independently of each other and of the tunneling t. The "spin" is encoded in the rotational degree of freedom of the molecules, while the interactions are controlled by applied static electric and continuous-wave microwave fields. Furthermore, we show that nuclear spins of the molecules can be used to implement an additional (orbital) degree of freedom that is coupled to the original rotational degree of freedom in a tunable way. The presented system is expected to exhibit exotic physics and to provide insights into strongly correlated phenomena in condensed matter systems. Realistic experimental imperfections are discussed.
%B Physical Review A
%V 84
%8 2011/9/15
%G eng
%U http://arxiv.org/abs/1106.1655v1
%N 3
%! Phys. Rev. A
%R 10.1103/PhysRevA.84.033619
%0 Journal Article
%J Physical Review Letters
%D 2011
%T Tunable Superfluidity and Quantum Magnetism with Ultracold Polar Molecules
%A Alexey V. Gorshkov
%A Salvatore R. Manmana
%A Gang Chen
%A Jun Ye
%A Eugene Demler
%A Mikhail D. Lukin
%A Ana Maria Rey
%X By selecting two dressed rotational states of ultracold polar molecules in an optical lattice, we obtain a highly tunable generalization of the t-J model, which we refer to as the t-J-V-W model. In addition to XXZ spin exchange, the model features density-density interactions and novel density-spin interactions; all interactions are dipolar. We show that full control of all interaction parameters in both magnitude and sign can be achieved independently of each other and of the tunneling. As a first step towards demonstrating the potential of the system, we apply the density matrix renormalization group method (DMRG) to obtain the 1D phase diagram of the simplest experimentally realizable case. Specifically, we show that the tunability and the long-range nature of the interactions in the t-J-V-W model enable enhanced superfluidity. Finally, we show that Bloch oscillations in a tilted lattice can be used to probe the phase diagram experimentally.
%B Physical Review Letters
%V 107
%8 2011/9/8
%G eng
%U http://arxiv.org/abs/1106.1644v1
%N 11
%! Phys. Rev. Lett.
%R 10.1103/PhysRevLett.107.115301