Electronic quasiparticles in the quantum dimer model: density matrix renormalization group results

TL;DR

This study uses density matrix renormalization group methods to analyze a quantum dimer model for cuprates, revealing small hole pockets in the Fermi surface and supporting the fractionalized Fermi liquid phase.

Contribution

It provides the first detailed DMRG analysis of the fermionic quasiparticles and Fermi surface in the quantum dimer model relevant to cuprate pseudogap states.

Findings

Fermi surface consists of small hole pockets near (π/2, π/2).

Fermi surface features persist up to doping of 1/16.

Entanglement entropy matches a sum of bosonic and fermionic contributions.

Abstract

We study a recently proposed quantum dimer model for the pseudogap metal state of the cuprates. The model contains bosonic dimers, representing a spin-singlet valence bond between a pair of electrons, and fermionic dimers, representing a quasiparticle with spin-$1/2$ and charge $+e$. By density matrix renormalization group calculations on a long but finite cylinder, we obtain the ground-state density distribution of the fermionic dimers for a number of different total densities. From the Friedel oscillations at open boundaries, we deduce that the Fermi surface consists of small hole pockets near $(\pi/2, \pi/2)$, and this feature persists up to a doping density of $1/16$. We also compute the entanglement entropy and find that it closely matches the sum of the entanglement entropies of a critical boson and a low density of free fermions. Our results support the existence of a fractionalized Fermi liquid in this model.