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arXiv · 1412.5597

Variational identification of a fractional Chern insulator in an extended Bose-Hubbard model

Hassan Shapourian·Bryan K. Clark
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Abstract

We study the extended Bose-Hubbard model on the square lattice at half filling as a function of next-nearest neighbor hopping amplitude and interaction strength. To variationally map out the phase diagram of this model, we develop a two-parameter family of wave-functions based on the parton construction which can describe both topological and broken symmetry phases on equal footing. In addition, our wave-functions resolve long standing issues with more conventional short-range Jastrow wave-functions. Using this variational ansatz, we show that a spontaneous time-reversal symmetry breaking fractional Chern insulator is energetically favored over a critical region between two superfluid phases. In verifying the properties of these parton wave-functions we exemplify a more robust way to identify topology through the Hall conductance.

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Hassan Shapourian, Bryan K. Clark. 2016-01-21. Variational identification of a fractional Chern insulator in an extended Bose-Hubbard model. https://doi.org/10.1103/physrevb.93.035125

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