Exact solution of a two-species quantum dimer model for pseudogap metals

TL;DR

This paper provides an exact solution for a two-species quantum dimer model that captures key features of the pseudogap phase in high-temperature superconductors, revealing a degenerate ground state and fractionalized Fermi liquid behavior.

Contribution

It introduces an exact ground state solution for a quantum dimer model with bosonic and fermionic dimers, elucidating properties of the pseudogap phase in cuprates.

Findings

Exact ground state wave functions at an arbitrary fermionic dimer density

Identification of a degenerate ground state line with a flat band of excitations

Perturbation leads to a fractionalized Fermi liquid with small Fermi pockets

Abstract

We present an exact ground state solution of a quantum dimer model introduced in Ref.[1], which features ordinary bosonic spin-singlet dimers as well as fermionic dimers that can be viewed as bound states of spinons and holons in a hole-doped resonating valence bond liquid. Interestingly, this model captures several essential properties of the metallic pseudogap phase in high-$T_c$ cuprate superconductors. We identify a line in parameter space where the exact ground state wave functions can be constructed at an arbitrary density of fermionic dimers. At this exactly solvable line the ground state has a huge degeneracy, which can be interpreted as a flat band of fermionic excitations. Perturbing around the exactly solvable line, this degeneracy is lifted and the ground state is a fractionalized Fermi liquid with a small pocket Fermi surface in the low doping limit.