title: Quantum tricriticality at the superfluid-insulator transition of binary Bose mixtures.
abstract: Quantum criticality near a tricritical point is studied in the two-component Bose-Hubbard model on square lattices. The existence of a quantum tricritical point on a boundary of a superfluid-insulator transition is confirmed by quantum Monte Carlo simulations. Moreover, we analytically derive the quantum tricritical behaviors on the basis of an effective field theory. We find two significant features of the quantum tricriticality that are its characteristic chemical potential dependence of the superfluid transition temperature and a strong density fluctuation. We suggest that these features are directly observable in existing experimental setups of Bose-Bose mixtures in optical lattices.
authors.affiliation: RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Kato
authors.affiliation: Condensed Matter Theory Laboratory, RIKEN, Wako, Saitama 351-0198, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Yamamoto
authors.affiliation: Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan and Computational Condensed Matter Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan.
authors.forename: Ippei
authors.initials: I
authors.lastname: Danshita