### Séminaire de groupe

Multicomponent Bose-Hubbard Model: Quantum Magnetism, Atomic-Molecular Mixtures and vice versa |

Laurent de Forges |

Université de Freiburg |

jeudi 23 mars 2017 , 10h25 |

Salle de séminaire du groupe de Physique Statistique |

Dieter Jaksch et al. [1] proposed in 1998 ultracold atoms setups as simulators for condensed matter physics, and they were right! 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 Hamiltonian, leading to multicomponent Bose-Einstein condensates, multiple transitions and quantum magnetism. Two systems particularly drew my attention: an atomic and molecular model [3], and a model with spin-spin interactions [4]. I have investigated these systems by using quantum Monte Carlo simulations and exact diagonalization method. I will show that these systems exhibit intriguing phases (e.g. Feshbach Insulator), as well as many phase transitions. <br><br> [1] D. Jaksch et al., PRL 81, 3108 (1998).<br> [2] M. Greiner et al., Nature 415, 39-44 (2002).<br> [3] L. de Forges et al., PRL 114, 195302 (2015).<br> [4] L. de Forges et al., PRL 113, 200402 (2014).<br> |