Hubbard-model

Superconductivity in hyperbolic spaces: Cayley trees, hyperbolic continuum, and BCS theory

We investigate $s$-wave superconductivity in negatively curved geometries, focusing on Cayley trees and the hyperbolic plane. Using a self-consistent Bogoliubov--de Gennes approach for trees and a BCS treatment of the hyperbolic continuum, we …

Superconductivity in hyperbolic spaces: Regular hyperbolic lattices and Ginzburg-Landau theory

We study $s$-wave superconductivity in hyperbolic spaces using the Bogoliubov-de Gennes theory for discrete hyperbolic lattices and the Ginzburg-Landau theory for the continuous hyperbolic plane. Hyperbolic lattices maintain a finite fraction of …

Symmetry breaking and spectral structure of the interacting Hatano-Nelson model

We study the Hatano-Nelson model, i.e., a one-dimensional non-Hermitian chain of spinless fermions with nearest-neighbor nonreciprocal hopping, in the presence of repulsive nearest-neighbor interactions. At half filling, we find two $\mathcal{PT}$ …