Optical-conductivity sum rule in cuprates and unconventional charge density waves: a short review

TL;DR

This paper reviews experimental findings on optical-conductivity spectral weight in cuprates and discusses theoretical models involving unconventional charge-density waves to explain these observations.

Contribution

It provides a concise overview of experimental data and evaluates recent theoretical models with unconventional charge-density waves in cuprates.

Findings

Spectral weight varies with temperature and doping in cuprates.

Unconventional $d_{x^2-y^2}$ charge-density waves can explain spectral weight behavior.

The review highlights the relevance of charge order in high-temperature superconductivity.

Abstract

We begin with an overview of the experimental results for the temperature and doping dependences of the optical-conductivity spectral weight in cuprate superconductors across the whole phase diagram. Then we discuss recent attempts to explain the observed behavior of the spectral weight using reduced and full models with unconventional $d_{x^2-y^2}$ charge-density waves.