Quasiparticle lifetime behaviour in a simplified self-consistent T-matrix treatment of the attractive Hubbard model in 2D

TL;DR

This paper investigates quasiparticle lifetimes in a 2D attractive Hubbard model, showing that including pair interactions results in lifetimes inversely proportional to temperature, aligning with experimental observations.

Contribution

It introduces a simplified self-consistent T-matrix approach to study quasiparticle lifetimes, emphasizing the role of pair interactions in the attractive Hubbard model.

Findings

Quasiparticle lifetimes vary linearly with inverse temperature when pair interactions are included.

The model captures short coherence lengths similar to cuprate superconductors.

Results are consistent with experimental data on quasiparticle behavior.

Abstract

The attractive Hubbard model on a 2-D square lattice is studied at low electronic densities using the ladder approximation for the pair susceptibility. This model includes (i) the short coherence lengths known to exist experimentally in the cuprate superconductors, and (ii) two-particle bound states that correspond to electron pairs. We study the quasiparticle lifetimes in both non self-consistent and self-consistent theories, the latter including interactions between the pairs. We find that if we include the interactions between pairs the quasiparticle lifetimes vary approximately linearly with the inverse temperature, consistent with experiment.