Superfluid density in cuprates: hints on gauge compositeness of the holes

TL;DR

This paper suggests that the superfluid density in hole-doped cuprates indicates a composite nature of holes, supported by a gauge approach that aligns well with experimental data across different doping levels.

Contribution

It introduces a gauge-theoretic framework to explain superfluid density features in cuprates, proposing hole compositeness as a key factor.

Findings

Consistent with 3D XY universality in underdoped cuprates.

Aligns with BCS-like behavior in overdoped cuprates.

Matches experimental superfluid density data across doping levels.

Abstract

We show that several features (the three-dimensional XY universality for moderate underdoping, the almost-BCS behaviour for moderate overdoping and the critical exponent) of the superfluid density in hole-doped cuprates hint at a composite structure of the holes. This idea can be implemented in a spin-charge gauge approach to the $t - t' - J$ model and provides indeed good agreement with available experimental data.