A two-step density-matrix renormalization-group study of coupled Luttinger liquids

TL;DR

This study uses a two-step density-matrix renormalization-group method to analyze a spinless fermion model on an anisotropic 2D lattice, revealing Fermi liquid behavior at weak coupling and pseudogap formation near a quantum critical point.

Contribution

It introduces a two-step DMRG approach to investigate single-particle and density correlations in coupled Luttinger liquids, highlighting quantum critical behavior.

Findings

Fermi liquid correlations at weak coupling

Sharp quasi-particle peak in spectral weight

Pseudogap formation near quantum critical point

Abstract

We report a two-step density-matrix renormalization-group computation of the equal-time single-particle Green's function, the density-density correlations, and the low-frequency spectral weight function of a spinless fermion model in an anisotropic two-dimensional lattice at half-filling. We find that at weak couplings the density-density correlations have the universal decay of a Fermi liquid; the spectral weight function displays a sharp quasi-particle peak. But in the vicinity of a quantum critical point, these correlations strongly deviate from a Fermi liquid prediction and a pseudogap opens in the spectral weight function.