Extended Bose-Hubbard models with ultracold magnetic atoms

Making magnetic atoms interact Two magnets interact with each other through a force that depends on the distance between them and on their mutual orientation. How do these long-range dipolar forces affect the behavior of a system of many magnets? Baier et al. used a gas of erbium atoms, which have a large magnetic moment, to answer this question. The gas—which they “housed” in an optical lattice—underwent a transition from a superfluid to an insulating state, revealing the presence of dipolar interactions through the orientation dependence of various properties. Science, this issue p. 201 A gas of magnetic erbium-168 atoms reveals effects of dipolar interactions on the superfluid–Mott insulator transition. The Hubbard model underlies our understanding of strongly correlated materials. Whereas its standard form only comprises interactions between particles at the same lattice site, extending it to encompass long-range interactions is predicted to profoundly alter the quantum behavior of the system. We realize the extended Bose-Hubbard model for an ultracold gas of strongly magnetic erbium atoms in a three-dimensional optical lattice. Controlling the orientation of the atomic dipoles, we reveal the anisotropic character of the onsite interaction and hopping dynamics and their influence on the superfluid-to-Mott insulator quantum phase transition. Moreover, we observe nearest-neighbor interactions, a genuine consequence of the long-range nature of dipolar interactions. Our results lay the groundwork for future studies of exotic many-body quantum phases.

[1]  N. Goldman,et al.  Dynamic Optical Lattices of Subwavelength Spacing for Ultracold Atoms. , 2015, Physical review letters.

[2]  R. Grimm,et al.  Ultracold Dipolar Molecules Composed of Strongly Magnetic Atoms. , 2015, Physical review letters.

[3]  I. Bloch,et al.  Crystallization in Ising quantum magnets , 2015, Science.

[4]  B. Naylor,et al.  Chromium dipolar Fermi sea , 2014, 1411.4634.

[5]  Jakub Zakrzewski,et al.  Non-standard Hubbard models in optical lattices: a review , 2014, Reports on progress in physics. Physical Society.

[6]  H. Nägerl,et al.  Observation of density-induced tunneling. , 2014, Physical review letters.

[7]  M. Mark,et al.  Quantum chaos in ultracold collisions of gas-phase erbium atoms , 2013, Nature.

[8]  U. P. E. M. Curie,et al.  Anisotropic optical trapping of ultracold erbium atoms , 2013, 1310.6149.

[9]  R. Grimm,et al.  Reaching Fermi degeneracy via universal dipolar scattering. , 2013, Physical review letters.

[10]  M. Yoneya,et al.  Physics of Liquid Crystals , 2014 .

[11]  Jun Ye,et al.  Observation of dipolar spin-exchange interactions with lattice-confined polar molecules , 2013, Nature.

[12]  A. Sharma,et al.  Nonequilibrium quantum magnetism in a dipolar lattice gas. , 2013, Physical review letters.

[13]  M. L. Wall,et al.  Dipole–dipole interactions in optical lattices do not follow an inverse cube power law , 2013, 1303.1230.

[14]  P. Zoller,et al.  Condensed matter theory of dipolar quantum gases. , 2012, Chemical reviews.

[15]  R. Grimm,et al.  Bose-Einstein condensation of erbium. , 2012, Physical review letters.

[16]  E. Zupanič,et al.  Narrow-line magneto-optical trap for erbium , 2012, 1203.1460.

[17]  Mingwu Lu,et al.  Quantum degenerate dipolar Fermi gas. , 2012, Physical review letters.

[18]  K. Sengstock,et al.  Multi-orbital and density-induced tunneling of bosons in optical lattices , 2011, 1108.3013.

[19]  Seo Ho Youn,et al.  Strongly dipolar Bose-Einstein condensate of dysprosium. , 2011, Physical review letters.

[20]  A. Daley,et al.  Precision measurements on a tunable Mott insulator of ultracold atoms. , 2011, Physical Review Letters.

[21]  S. Müller,et al.  Stability of a dipolar Bose-Einstein condensate in a one-dimensional lattice , 2011, 1105.5015.

[22]  M. Lewenstein,et al.  Ultracold dipolar gases in optical lattices , 2011, 1103.3145.

[23]  M. Troyer,et al.  Supersolid phase with cold polar molecules on a triangular lattice. , 2009, Physical review letters.

[24]  M. Lewenstein,et al.  Quantum phases of cold polar molecules in 2D optical lattices. , 2009, Physical review letters.

[25]  M. Lewenstein,et al.  The physics of dipolar bosonic quantum gases , 2009, 0905.0386.

[26]  P. Zoller,et al.  State-dependent, addressable subwavelength lattices with cold atoms , 2008, 0801.0600.

[27]  I Bloch,et al.  Time-Resolved Observation and Control of Superexchange Interactions with Ultracold Atoms in Optical Lattices , 2007, Science.

[28]  C. P. Sun,et al.  Novel quantum phases of dipolar bose gases in optical lattices. , 2006, Physical review letters.

[29]  D. Jaksch,et al.  Signatures of the superfluid to Mott-insulator transition in the excitation spectrum of ultracold atoms , 2006, cond-mat/0604625.

[30]  C. Ospelkaus,et al.  Localization of bosonic atoms by fermionic impurities in a three-dimensional optical lattice. , 2006, Physical review letters.

[31]  W. Hofstetter,et al.  Spectroscopy of ultracold atoms by periodic lattice modulations. , 2006, Physical review letters.

[32]  M. Oberthaler,et al.  Dynamics of Bose-Einstein condensates in optical lattices , 2006 .

[33]  S. Giampaolo,et al.  Extended Bose Hubbard model of interacting bosonic atoms in optical lattices: From superfluidity to density waves , 2005, cond-mat/0509161.

[34]  M. Troyer,et al.  Supersolid hard-core bosons on the triangular lattice. , 2005, Physical review letters.

[35]  S. Das Sarma,et al.  Quantum phases of the extended Bose-Hubbard hamiltonian: possibility of a supersolid state of cold atoms in optical lattices. , 2005, Physical review letters.

[36]  A. Griesmaier,et al.  Bose-Einstein condensation of chromium. , 2005, Physical review letters.

[37]  T. Esslinger,et al.  Transition from a strongly interacting 1d superfluid to a Mott insulator. , 2003, Physical review letters.

[38]  T. Hänsch,et al.  Collapse and revival of the matter wave field of a Bose–Einstein condensate , 2002, Nature.

[39]  H. Häffner,et al.  A Bose-Einstein condensate in an optical lattice , 2002, cond-mat/0206063.

[40]  T. Hänsch,et al.  Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms , 2002, Nature.

[41]  L. You,et al.  Trapped atomic condensates with anisotropic interactions , 2000, cond-mat/0002079.

[42]  J. Zaanen.  Quantum phase transitions in cuprates: stripes and antiferromagnetic supersolids , 1998, cond-mat/9811078.

[43]  C. Gardiner,et al.  Cold Bosonic Atoms in Optical Lattices , 1998, cond-mat/9805329.

[44]  Kampf,et al.  Simultaneous diagonal and off-diagonal order in the Bose-Hubbard Hamiltonian. , 1994, Physical review. B, Condensed matter.

[45]  A. Auerbach.  Interacting electrons and quantum magnetism , 1994 .

[46]  K. Dill.  Dominant forces in protein folding. , 1990, Biochemistry.

[47]  R. Micnas,et al.  Superconductivity in narrow-band systems with local nonretarded attractive interactions , 1990 .

[48]  Fisher,et al.  Boson localization and the superfluid-insulator transition. , 1989, Physical review. B, Condensed matter.

[49]  Gould,et al.  Diffraction of atoms by light: The near-resonant Kapitza-Dirac effect. , 1986, Physical review letters.