Algebraic charge liquids

TL;DR

This paper introduces 'algebraic charge liquids', a new theoretical state of matter that explains conflicting experimental observations of zero energy electrons in cuprate superconductors and predicts novel experimental outcomes.

Contribution

The paper proposes a novel theoretical framework called algebraic charge liquids that unifies disparate experimental results in high-temperature superconductors.

Findings

Reconciles resistance oscillation and photoemission data

Explains the dependence of superconducting electron density on total electron density

Predicts new experimental signatures of algebraic charge liquids

Abstract

High temperature superconductivity emerges in the cuprate compounds upon changing the electron density of an insulator in which the electron spins are antiferromagnetically ordered. A key characteristic of the superconductor is that electrons can be extracted from them at zero energy only if their momenta take one of four specific values (the `nodal points'). A central enigma has been the evolution of the zero energy electrons in the metallic state between the antiferromagnet and the superconductor, and recent experiments yield apparently contradictory results. The oscillation of the resistance in this metal as a function of magnetic field indicate that the zero energy electrons carry momenta which lie on elliptical `Fermi pockets', while ejection of electrons by high intensity light indicates that the zero energy electrons have momenta only along arc-like regions. We present a theory of new states of matter, which we call `algebraic charge liquids', which arise naturally between the antiferromagnet and the superconductor, and reconcile these observations. Our theory also explains a puzzling dependence of the density of superconducting electrons on the total electron density, and makes a number of unique predictions for future experiments.