BCS theory of time-reversal-symmetric Hofstadter-Hubbard model

R. O. Umucalilar; M. Iskin

doi:10.1103/physrevlett.119.085301

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arXiv · 1704.07755

BCS theory of time-reversal-symmetric Hofstadter-Hubbard model

R. O. Umucalilar·M. Iskin

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Abstract

The competition between the length scales associated with the periodicity of a lattice potential and the cyclotron radius of a uniform magnetic field is known to have dramatic effects on the single-particle properties of a quantum particle, e.g., the fractal spectrum is known as the Hofstadter butterfly. Having this intricate competition in mind, we consider a two-component Fermi gas on a square optical lattice with opposite synthetic magnetic fields for the components, and study its effects on the many-body BCS-pairing phenomenon. By a careful addressing of the distinct superfluid transitions from the semi-metal, quantum spin-Hall insulator or normal phases, we explore the low-temperature phase diagrams of the model, displaying lobe structures that are reminiscent of the well-known Mott-insulator transitions of the Bose-Hubbard model.

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R. O. Umucalilar, M. Iskin. 2017-08-02. BCS theory of time-reversal-symmetric Hofstadter-Hubbard model. https://doi.org/10.1103/physrevlett.119.085301

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