Exact correlation functions in the cuprate pseudogap phase: combined effects of charge order and pairing

TL;DR

This paper derives exact correlation functions in the cuprate pseudogap phase, showing how different charge order and pairing theories uniquely influence two-body physics, especially spin responses, aiding experimental distinction.

Contribution

It provides a method to exactly compute correlation functions from mean field theories using the Ward-Takahashi identity, linking microscopic mechanisms to observable two-body physics.

Findings

Distinct spin response signatures for pair density wave versus other theories

Exact vertex functions derived from Ward-Takahashi identity

Theoretical framework applicable to various charge and pairing scenarios

Abstract

There is a multiplicity of charge ordered, pairing-based or pair density wave theories of the cuprate pseudogap, albeit arising from different microscopic mechanisms. For mean field schemes (of which there are many) we demonstrate here that they have precise implications for two body physics in the same way that they are able to address the one body physics of photoemission spectroscopy. This follows because the full vertex can be obtained exactly from the Ward-Takahashi identity. As an illustration, we present the spin response functions, finding that a recently proposed pair density wave (Amperean pairing) scheme is readily distinguishable from other related scenarios.