One-Particle Anomalous Excitations of Gutzwiller Projected BCS Superconductors and Bogoliubov Quasi-Particle Characteristics

TL;DR

This paper demonstrates that Gutzwiller projected BCS superconductors exhibit highly coherent low-lying anomalous excitations that can be accurately described by a renormalized Bogoliubov quasi-particle framework, aligning with experimental and numerical findings.

Contribution

It shows that the low-energy excitations in Gutzwiller projected BCS states are well described by a renormalized BCS theory, clarifying their quasi-particle nature.

Findings

Highly coherent anomalous excitations in projected BCS states

Quantitative agreement with renormalized BCS spectrum

Consistency with numerical and experimental data

Abstract

Low-lying one-particle anomalous excitations are studied for Gutzwiller projected strongly correlated BCS states. It is found that the one-particle anomalous excitations are highly coherent, and the numerically calculated spectrum can be reproduced quantitatively by a renormalized BCS theory, thus strongly indicating that the nature of low-lying excitations described by the projected BCS states is essentially understood within a renormalized Bogoliubov quasi-particle picture. This finding resembles a well known fact that a Gutzwiller projected Fermi gas is a Fermi liquid. The present results are consistent with numerically exact calculations of the two-dimensional t-J model as well as recent photoemission experiments on high-T_{\rm C} cuprate superconductors.