Competing exotic quantum phases of spin-$1/2$ ultra-cold lattice bosons with extended spin interactions

Abstract

Advances in pure optical trapping techniques now allow the creation of degenerate Bose gases with internal degrees of freedom. Systems such as ${}^{87}$Rb, ${}^{39}$K or ${}^{23}$Na in the $F=1$ hyperfine state offer an ideal platform for studying the interplay of superfluidity and quantum magnetism. Motivated by the experimental developments, we study ground state phases of a two-component Bose gas loaded on an optical lattice. The system is described effectively by the Bose-Hubbard Hamiltonian with onsite and near neighbor spin-spin interactions. An important feature of our investigation is the inclusion of interconversion (spin flip) terms between the two species, which has been observed in optical lattice experiments. Using mean-field theory and quantum Monte Carlo simulations, we map out the phase diagram of the system. A rich variety of phases is identified, including antiferromagnetic (AF) Mott insulators, ferromagnetic and AF superfluids.

11 pages, 10 figures, revised version

References in corpus (8)

• Coherent collisional spin dynamics in optical lattices
• Directed update for the Stochastic Green Function algorithm
• Spin-1 bosons with coupled ground states in optical lattices
• Phases of a 2D Bose Gas in an Optical Lattice
• First- and second-order superfluid--Mott-insulator phase transitions of spin-1 bosons with coupled ground states in optical lattices
• Comment on "Feshbach-Einstein Condensates" by V. G. Rousseau and P. J. H. Denteneer
• Phase diagram of spin-1/2 bosons in one-dimensional optical lattice
• Complex phases in the doped two-species bosonic Hubbard Model

Cited by in corpus (3)

• Spin-1 Bose Hubbard model with nearest neighbour extended interaction
• Quantum phases of a spin-1 ultracold Bose gas with three body interactions
• Effects of an attractive three body interaction on a spin-1 Bose Hubbard model