Breakdown of Strong-Coupling Perturbation Theory in Doped Mott Insulators

TL;DR

This paper demonstrates that in doped Mott insulators, the quasiparticle weight depends critically on high energy scales, revealing a breakdown of strong-coupling perturbation theory due to quantum interference effects.

Contribution

It uncovers the asymptotic dependence of quasiparticle weight on high energy scales and explains broad spectral features in cuprates as a consequence of high energy slavery.

Findings

Quasiparticle weight depends on the high energy scale near half-filling.

Quantum interference causes the breakdown of strong-coupling perturbation theory.

Broad spectral features in cuprates arise from high energy slavery.

Abstract

We show that doped Mott insulators, such as the copper-oxide superconductors, are asymptotically slaved in that the quasiparticle weight, $Z$, near half-filling depends critically on the existence of the high energy scale set by the upper Hubbard band. In particular, near half filling, the following dichotomy arises: $Z\ne 0$ when the high energy scale is integrated out but Z=0 in the thermodynamic limit when it is retained. Slavery to the high energy scale arises from quantum interference between electronic excitations across the Mott gap. Broad spectral features seen in photoemission in the normal state of the cuprates are argued to arise from high energy slavery.