Bulletin of the American Physical Society
APS March Meeting 2015
Volume 60, Number 1
Monday–Friday, March 2–6, 2015; San Antonio, Texas
Session J36: Bosons in Optical Lattices 
Hide Abstracts 
Sponsoring Units: DAMOP Chair: Randall Hulet, Rice University Room: 211 
Tuesday, March 3, 2015 2:30PM  2:42PM 
J36.00001: Phase diagram of the Bilayer Bose Hubbard Model Yanfei Tang, Vito Scarola Optical lattices can be tailored to realized a variety of different geometries. We model bosons confined to a bilayer configuration to allow a pseudospin degree of freedom in the layer index. Specifically, we model the BoseHubbard model on a bilayer square lattice with variable interlayer hopping. Without the presence of interlayer hopping, the phase diagram only presents well known superfluid or Mott insulating phases. But interlayer hopping allows coupling of these two states. We find that an interesting incompressible phase emerges at half filling as we increase the interlayer hopping strength. We study the low temperature physics of the new phase and address the nature of pseudospin correlations in observables. We pair our effective theory with a quantum Monte Carlo study. [Preview Abstract] 
Tuesday, March 3, 2015 2:42PM  2:54PM 
J36.00002: Controlling coherence via tuning of the population imbalance in a bipartite optical lattice Marco Fedele Di Liberto The control of transport properties is a key tool at the basis of many technologically relevant effects in condensed matter. The clean and precisely controlled environment of ultracold atoms in optical lattices allows one to prepare simplified but instructive models, which can help to better understand the underlying physical mechanisms. Here we show that by tuning a structural deformation of the unit cell in a bipartite optical lattice, one can induce a phase transition from a superfluid into various Mott insulating phases forming a shell structure in the superimposed harmonic trap. The Mott shells are identified via characteristic features in the visibility of Bragg maxima in momentum spectra. The experimental findings are explained by Gutzwiller meanfield and quantum Monte Carlo calculations. Our system bears similarities with the loss of coherence in cuprate superconductors, known to be associated with the doping induced buckling of the oxygen octahedra surrounding the copper sites. [Preview Abstract] 
Tuesday, March 3, 2015 2:54PM  3:06PM 
J36.00003: Quantum Phase Transitions in mixtures of two identical Bosonic Species Fabio Lingua, Marco Guglielmino, Barbara Capogrosso Sansone, Vittorio Penna We investigate the phase diagram of a twocomponent bosonic systems in a square lattice by means of quantum Monte Carlo simulation. Depending on the interplay between inter and intraspecies interactions we show the existence of intersting quantum phases such as, among others a demixed superfluid, a demixed Mott insulator, supercounterflow. [Preview Abstract] 
Tuesday, March 3, 2015 3:06PM  3:18PM 
J36.00004: Thermodynamics in an extended meanfield theory for the BoseHubbard model Dario Huegel, Lode Pollet We derive an extended meanfield formalism to study the thermodynamical properties of the BoseHubbard model. The framework can be viewed as the zerofrequency limit of bosonic dynamical meanfield theory (BDMFT), but equally well as an extension of the meanfield approximation in which pair creation and annihilation of depleted particles is taken into account. The selfenergy is treated variationally, minimizing the grand potential. We find that the $T=0$ phase diagrams of the 3d and 2d BoseHubbard model are reproduced with an accuracy of $1 \%$ with just $3$ free (physical) parameters that are determined selfconsistently. The superfluid to normal transition at finite temperature is reproduced well but less accurately than in BDMFT. [Preview Abstract] 

J36.00005: ABSTRACT WITHDRAWN 
Tuesday, March 3, 2015 3:30PM  3:42PM 
J36.00006: Minimizing NonAdiabadicities In Optical Lattice Loading Michele Dolfi, Adrian Kantian, Bela Bauer, Matthias Troyer In the quest to reach lower temperatures of ultracold gases in optical lattice experiments, nonadiabaticites during lattice loading are one of the limiting factors that prevent the same low temperatures to be reached as in experiments without lattice. Simulating the loading of a bosonic quantum gas into a onedimensional optical lattice with and without a trap, we find that the redistribution of atomic density inside a global confining potential is by far the dominant source of heating. Based on these results we propose to adjust the trapping potential during loading to minimize changes to the density distribution. Our simulations confirm that a very simple linear interpolation of the trapping potential during loading already significantly decreases the heating of a quantum gas and we discuss how loading protocols minimizing density redistributions can be designed. [Preview Abstract] 
Tuesday, March 3, 2015 3:42PM  3:54PM 
J36.00007: Tunable anisotropic superfluidity in optical Kagome superlattice Axel Pelster, XueFeng Zhang, Tao Wang, Sebastian Eggert We study the extended BoseHubbard model for the optical Kagome superlattice which is generated by enhancing the long wavelength laser in one direction. By combining Quantum Monte Carlo simulations with the Generalized Effective Potential Landau Theory, we find not only the Mott insulatorsuperfluid quantum phase transition, but also striped solid phases with noninteger filling factors. Furthermore, we determine with high accuracy the quantum phase diagram for different trap potential offsets. Due to the delicate interplay between onsite repulsion and artificial symmetry breaking, the superfluid density turns out to be anisotropic which reveals its tensorial property. Counterintuitively, the bias of the anisotropy is alternating between $x$ and $y$direction while tuning the particle number or the hopping strength. Finally, we discuss how to observe such phenomenon experimentally, in particular via timeofflight absorption measurements. [Preview Abstract] 
Tuesday, March 3, 2015 3:54PM  4:06PM 
J36.00008: Spin Meissner Effect and Chiral Mott Insulators in Quantum Ladders Alexandru Petrescu, Karyn Le Hur We introduce generic bosonic models exemplifying that chiral Meissner currents can persist in insulating phases of matter. We first consider interacting bosons on a twoleg ladder. The total density sector can be gapped in a bosonic Mott insulator at oddinteger filling, while the relative density sector remains superfluid due to interchain hopping. Coupling the relative density to gauge fields yields a pseudospin Meissner effect [1]. We show that the same phase arises if the bosons are replaced by spinful fermions confined in Cooper pairs, and find a dual fermionic Mott insulator with spinon currents [2]. We propose two experimental realizations, one with ultracold atoms in the setup of [3], and another with Josephson junction arrays. Finally, we discuss the possibility to explore Laughlin phases in these systems by tuning the magnetic flux and the density of bosons [4]. \\[4pt] [1] Alexandru Petrescu and Karyn Le Hur, Phys. Rev. Lett. 111, 150601 (2013) \\[0pt] [2] Alexandru Petrescu and Karyn Le Hur, arXiv:1410.6105 \\[0pt] [3] M. Atala et al. Nat. Phys. 10, 588 (2014). \\[0pt] [4] C. L. Kane, R. Mukhopadhyay and T. C. Lubensky, Phys. Rev. Lett. 88, 036401 (2002); J. C. Y. Teo and C. L. Kane, Phys. Rev. B 89, 085101 (2014). [Preview Abstract] 

J36.00009: ABSTRACT WITHDRAWN 
Tuesday, March 3, 2015 4:18PM  4:30PM 
J36.00010: Porbital Condensations of Twospecies Bose Mixture in Optical Lattice JhihShih You, IKang Liu, DawWei Wang, ShihChuan Gou, Congjun Wu We investigate the $p$orbital BoseEinstein condensations~(BECs) of twospecies mixture in a bipartite optical lattice. A new imaginarytime propagation method is developed to numerically solve the GrossPitaevskii equation with truncating states below the $p$ bands, which can be applicable to even higher orbital bands. Our study confirms that the intraspecies interactions favor complex timereversal broken BECs with staggered orbital currents. However, when the interspecies interaction increases, the complex condensate state undergoes a quantum phase transition toward a realvalued TR invariant condensate with staggered spin density structure. We discuss the origin and properties of such phase transition and its implication in the experimental measurement. [Preview Abstract] 
Tuesday, March 3, 2015 4:30PM  4:42PM 
J36.00011: The Abelian Higgs model on Optical Lattice? Yannick Meurice, ShanWen Tsai, Alexei Bazavov, Jin Zhang We study the Lattice Gauge Theory of the U(1)Higgs model in 1+1 dimensions in the strongly coupled regime. We discuss the plaquette corrections to the effective theory where link variables are integrated out. We discuss matching with the secondorder perturbation theory effective Hamiltonian for various BoseHubbard models. This correspondence can be exploited for building a lattice gauge theory simulator on optical lattices. We propose to implement the quantum rotors which appear in the Hamiltonian formulation using Bose mixtures or porbitals. Recent progress on magnetic effects in 2+1 dimensions will be discussed. [Preview Abstract] 
Tuesday, March 3, 2015 4:42PM  4:54PM 
J36.00012: Coldatom quantum simulation of U(1) lattice gaugeHiggs model Kenichi Kasamatsu, Yoshihito Kuno, Yoshiro Takahashi, Ikuo Ichinose, Tetsuo Matsui We discuss the possible methods to construct a quantum simulator of the U(1) lattice gaugeHiggs model using cold atoms in an optical lattice. These methods require no severe fine tunings of parameters of atomicinteractions in contrast with the other previous literature. We propose some realistic experimental setups to realize the atomic quantum simulator of the U(1) lattice gaugeHiggs model in a twodimensional optical lattice. Our target gaugeHiggs model has a nontrivial phase structure, i.e., existence of the phase boundary between confinement and Higgs phases, and this phase boundary is to be observed by coldatom experiments. As a reference to such experiments, we make numerical simulations of the timedependent GrossPitaevskii equation and observe the realtime dynamics of the atomic simulators. Clarification of the dynamics of this gaugeHiggs model sheds some lights upon various unsolved problems including the inflation process of the early universe. [Preview Abstract] 
Tuesday, March 3, 2015 4:54PM  5:06PM 
J36.00013: Chiral Bosonic Phases on the Haldane Honeycomb Lattice Ivana Vasic, Alexandru Petrescu, Karyn Le Hur, Walter Hofstetter Motivated by its recent realization in an ultracold atom experiment [1], we investigate the honeycomb lattice tightbinding model introduced by Haldane [2], for bosons with local interactions at the average filling of one boson per site [3]. We uncover in the ground state phase diagram three phases: a uniform superfluid (SF), a chiral superfluid (CSF) and a plaquette Mott insulator with local current loops (PMI). Nearestneighbor and nextnearest neighbor currents distinguish CSF from SF, and the phase transition between them is first order. We apply bosonic dynamical mean field theory and exact diagonalization to obtain the zero temperature phase diagram, complementing numerics with calculations of excitation spectra in strong and weak coupling perturbation theory. Furthermore, we explore the possibility of chiral Mott insulating phases at the average filling of one boson every two sites. The characteristic density fluctuations, current correlation functions, and excitation spectra are measurable in ultracold atom experiments. [1] G. Jotzu et al., arXiv:1406.7874 [2] F. D. M. Haldane, Phys. Rev. Lett. 61, 2015 (1988). [3] Ivana Vasic, Alexandru Petrescu, Karyn Le Hur, Walter Hofstetter, arXiv:1408.1411 [Preview Abstract] 
Tuesday, March 3, 2015 5:06PM  5:18PM 
J36.00014: Strongcoupling theory approach to describe an atomtronic josephson junction on an optical lattice Manjari Gupta, H.R. Krishnamurthy, J.K. Freericks We examine the behavior of a bose superfluid on an optical lattice in the presence of an annular trap and a barrier across the annular region which acts as a Josephson junction. As the superfluid is rotated it moves with a supercurrent until it develops phase slips which generate vortices. We use a finite temperature strongcoupling ($t/U$) expansion about the meanfield solution of the Bose Hubbard model, as described in our earlier paper Ref. \footnote{M. Gupta, H. R. Krishnamurthy and J. K. Freericks, Phys. Rev. A \textbf{88}, 053636 (2013).}, to characterize the device. Although our formalism is in equilibrium, it allows us to study the superfluid current flow and the generation of phase slips. This theory should aid in the further development of atomtronic circuits (\footnote{B. T. Seaman, M. Kr\"amer, D. Z. Anderson, M. J. Holland Phys. Rev. A \textbf{75}, 023615 (2007).}, \footnote{R. A. Pepino, J. Cooper, D. Z. Anderson and M. J. Holland, Phys. Rev. Lett. \textbf{103}, 140405 (2009).}). In addition, we show how even more complex Josephson junction structures spontaneously arise if the filling is increased to generate Mott regions within the system. [Preview Abstract] 
Tuesday, March 3, 2015 5:18PM  5:30PM 
J36.00015: The Quantum Dynamics of a Dilute Gas in a 3D BCC Optical Lattice Linda Reichl, Yingyue Boretz The classical and quantum dynamics of a dilute gas of rubidium atoms, in a 3D bodycentered cubic optical lattice, is studied for a range of polarizations of the laser beams forming the lattice. The relative polarization of the lasers determines the the structure of the potential energy seen by the rubidium atoms. If three pairs of inphase mutually perpendicular laser beams, with the same wavelength, form the lattice, only a limited range of possible couplings can be realized in the lab. We have determined the band structure of the BCC optical lattice for all theoretically possible couplings, and find that the band structure for lattices realizable in the lab, differs significantly from that expected for a BCC crystal. As coupling is increased, the lattice becomes increasingly chaotic [1] and it becomes possible to produce band structure that has qualitative similarity to a BCC.\\[4pt] [1] Horsley, S. Koppel, and L.E. Reichl, ``Chaotic Dynamics in a twodimensional optical lattice,'' Phys. Rev. E \textbf{89} 012917 (2014). [Preview Abstract] 
Follow Us 
Engage
Become an APS Member 
My APS
Renew Membership 
Information for 
About APSThe American Physical Society (APS) is a nonprofit membership organization working to advance the knowledge of physics. 
© 2021 American Physical Society
 All rights reserved  Terms of Use
 Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 207403844
(301) 2093200
Editorial Office
1 Research Road, Ridge, NY 119612701
(631) 5914000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 200452001
(202) 6628700