A Variational Monte Carlo Study of the Current Carried by a Quasiparticle

TL;DR

This study uses variational Monte Carlo methods with Gutzwiller-projected states to analyze how quasiparticle currents and spectral weights are renormalized in high-temperature superconductors, revealing doping-dependent behaviors.

Contribution

It introduces a novel application of Gutzwiller-projected variational states to quantify current renormalization and spectral weight in high-Tc superconductors.

Findings

Current renormalization decreases with doping and vanishes at zero doping.

Spectral weight Z_+ shows a k-space structure near the Fermi surface.

Perturbative corrections to these quantities are discussed.

Abstract

With the use of Gutzwiller-projected variational states, we study the renormalization of the current carried by the quasiparticles in high-temperature superconductors and of the quasiparticle spectral weight. The renormalization coefficients are computed by the variational Monte Carlo technique, under the assumption that quasiparticle excitations may be described by Gutzwiller-projected BCS quasiparticles. We find that the current renormalization coefficient decreases with decreasing doping and tends to zero at zero doping. The quasiparticle spectral weight Z_+ for adding an electron shows an interesting structure in k space, which corresponds to a depression of the occupation number k just outside the Fermi surface. The perturbative corrections to those quantities in the Hubbard model are also discussed.