Motivated by a scarcity of simple and analytically tractable models
of superconductivity from strong repulsive interactions, we introduce a
simple tight-binding lattice model of fermions with repulsive
interactions that exhibits unconventional superconductivity (beyond BCS
theory). The model resembles an idealized trilayer. The Cooper pair
consists of electrons on opposite sides of the dielectric, which
mediates the attraction. In the strong coupling limit, we use degenerate
perturbation theory to show that the model reduces to a superconducting
hard-core Bose-Hubbard model. Above the superconducting critical
temperature, an analog of pseudo-gap physics results where the fermions
remain Cooper paired with a large single-particle energy gap.
Study of hard core repulsive interactions in an hadronic gas from a comparison with lattice QCD
