Two-mode variational Monte Carlo study of Quasiparticle excitations in cuprates

TL;DR

This study uses a novel two-mode variational Monte Carlo approach to investigate quasiparticle excitations in cuprates, successfully explaining experimental anomalies without extrinsic effects and resolving longstanding spectral weight sum rule issues.

Contribution

Introduces a new two-mode VMC method to analyze quasiparticles in the t-J model, providing insights consistent with experiments and addressing previous theoretical challenges.

Findings

Reproduces doping-independent Fermi velocity

Identifies two energy scales in spectral function

Explains suppression of low energy spectral weight

Abstract

Recent measurements of quasiparticles in hole-doped cuprates reveal highly unusual features: 1) the doping-independent Fermi velocity, 2) two energy scales in the quasiparticle spectral function, and 3) a suppression of the low energy spectral weight near the zone center. The underlying mechanism is under hot debate. We addressed these important issues by a novel two-mode variational Monte Carlo (VMC) study of the t-J model. We obtained results in agreement with the experiments but without invoking extrinsic effects. Besides, we resolved a long standing issue of the sum rule for quasiparticle spectral weights in VMC studies. The electron doped case was also discussed.