Gauge invariance and electron spectral functions in underdoped cuprates

TL;DR

This paper investigates the electron spectral function in underdoped cuprates using a slave particle approach, highlighting the role of gauge fields in explaining experimental spectral line-shapes and addressing anomalous dimensions.

Contribution

It introduces a gauge-invariant analysis within the slave particle framework to explain spectral features and anomalous behaviors in underdoped cuprates.

Findings

Massless gauge fields explain broad spectral line-shapes.

Incorporation of anomalous dimensions aligns theory with experimental phenomenology.

Reinterpretation of gauge-invariant amplitudes clarifies physical implications.

Abstract

The single particle spectral function for the normal state of underdoped high $T_c$ cuprates is studied within the slave particle framework. We find that the presence of a massless dynamical gauge field - a direct consequence of the quantum order - explains the broad, but not totally incoherent, line-shapes observed in experiments. The issue of the negative anomalous dimension of a recently proposed gauge invariant single particle amplitude is also considered. We show how the anomalous behavior of the single particle amplitude can be incorporated within the slave particle approach and, thus reinterpreted, lead to physical phenomenology.