Higgs criticality in a two-dimensional metal

TL;DR

This paper proposes a theory for the strange metal phase in cuprates involving a Higgs-driven quantum phase transition between two metallic states with different Fermi surface sizes, without symmetry breaking.

Contribution

It introduces a novel Higgs transition framework involving emergent gauge fields to explain the strange metal behavior in cuprates, connecting theory with experiments.

Findings

Identifies a Higgs transition between large and small Fermi surface metals.

Links the transition to antiferromagnetic correlations via a Higgs field.

Proposes a global phase diagram consistent with cuprate experiments.

Abstract

We analyze a candidate theory for the strange metal near optimal hole-doping in the cuprate superconductors. The theory contains a quantum phase transition between metals with large and small Fermi surfaces of spinless fermions carrying the electromagnetic charge of the electron, but the transition does not directly involve any broken global symmetries. The two metals have emergent SU(2) and U(1) gauge fields respectively, and the transition is driven by the condensation of a real Higgs field, carrying a finite lattice momentum and an adjoint SU(2) gauge charge. This Higgs field measures the local antiferromagnetic correlations in a "rotating reference frame". We propose a global phase diagram around this Higgs transition, and describe its relationship to a variety of recent experiments on the cuprate superconductors.