Loss of superfluidity by fermions in the boson Hubbard model on an optical lattice

Abstract

The experimentally observed loss of superfluidity by introducing fermions to the boson Hubbard system on an optical lattice is explained. We show that the virtual transitions of the bosons to the higher Bloch bands, coupled with the contact boson-fermion interactions of either sign, result in an effective increase of the boson on-site repulsion. If this renormalization of the on-site potential is dominant over the fermion screening of the boson interactions, the Mott insulating lobes of the Bose-Hubbard phase diagram will be enhanced for either sign of the boson-fermion interactions. We discuss implications for cold atom experiments where the expansion of the Mott lobes by fermions has been conclusively established.

4 pages, 1 eps figure, minor changes

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Cited by in corpus (7)

• Non-standard Hubbard models in optical lattices: a review
• Interaction Driven Interband Tunneling of Bosons in the Triple Well
• Effect of interactions on harmonically confined Bose-Fermi mixtures in optical lattices
• Zero-temperature phase diagram of Bose-Fermi gaseous mixtures in optical lattices
• Effects of a dilute gas of fermions on the superfluid-insulator phase diagram of the Bose-Hubbard model
• Bose-Fermi solid and its quantum melting in an one-dimensional optical lattice
• Sign reversal of the boson-boson interaction potential in planar Bose-Fermi mixtures under a synthetic magnetic field