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Strong-coupling perturbation theory for the two-dimensional Bose-Hubbard model in a magnetic field

M. Niemeyer·J. K. Freericks·H. Monien
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Abstract

The Bose-Hubbard model in an external magnetic field is investigated with strong-coupling perturbation theory. The lowest-order secular equation leads to the problem of a charged particle moving on a lattice in the presence of a magnetic field, which was first treated by Hofstadter. We present phase diagrams for the two-dimensional square and triangular lattices, showing a change in shape of the phase lobes away from the well-known power-law behavior in zero magnetic field. Some qualitative agreement with experimental work on Josephson-junction arrays is found for the insulating phase behavior at small fields.

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M. Niemeyer, J. K. Freericks, H. Monien. 1998-12-15. Strong-coupling perturbation theory for the two-dimensional Bose-Hubbard model in a magnetic field. https://doi.org/10.1103/physrevb.60.2357

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