Séminaire du LPTMS: Laurent de Forges de Parny

Multicomponent Bose-Hubbard Model: Quantum Magnetism and Atomic-Molecular Mixtures

Laurent de Forges de Parny (Albert-Ludwigs University of Freiburg, Germany)

Dieter Jaksch et al. [1] proposed in 1998 ultracold atoms setups as simulators for condensed matter physics. Following this idea, Markus Greiner et al. [2] reported in 2002 the first experimental implementation of the Bose-Hubbard model at zero temperature. This pioneering experiment, which allows for the direct observation of the quantum phase transition from a superfluid to a Mott insulator state, has definitely opened a novel area of research. Since 15 years, a huge amount of researchers, including me, is motivated by the observation of new quantum phases and phase transitions.

In particular, recent progress in the field have allowed the study of bosonic systems with multiple components, such as bosons with spin degree of freedom and atomic-molecular mixtures. The richness of these systems comes from the competition between different terms of the extended Bose-Hubbard Hamiltonian, leading to multicomponent Bose-Einstein condensates, multiple transitions and quantum magnetism.

Two systems particularly drew my attention: an atomic and molecular mixtures [3], and a model of spin-1 atoms with spin-spin interactions [4]. We have investigated these systems using quantum Monte Carlo simulations and exact diagonalization method. I will show that these systems exhibit intriguing phases (e.g. Feshbach Insulator, molecular superfluid), as well as many phase transitions (XY, Ising and BKT).

References:

  1. D. Jaksch, C. Bruder, J. I. Cirac, C. W. Gardiner and P. Zoller, Cold Bosonic Atoms in Optical Lattices, Phys. Rev. Lett. 81, 3108 (1998)
  2. M. Greiner, O. Mandel, T. Esslinger, T. W. Hänsch & I. Bloch, Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms, Nature 415, 39-44 (2002)
  3. L. de Forges de Parny, V. G. Rousseau, and T. Roscilde, Feshbach-Stabilized Insulator of Bosons in Optical Lattices, Phys.Rev.Lett. 114, 195302 (2015)
  4. Laurent de Forges de Parny, Hongyu Yang, and Frédéric Mila, Anderson Tower of States and Nematic Order of Spin-1 Bosonic Atoms on a 2D Lattice, Phys.Rev.Lett. 113, 200402 (2014)

Date/Time : 27/02/2018 - 06/03/2018 - 11:00 - 12:00

Location : LPTMS, salle 201, 2ème étage, Bât 100, Campus d'Orsay

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