# The splitting of electrons and violation of the Luttinger sum rule

## TL;DR

This paper introduces a novel theoretical framework for strongly correlated electrons using su(2|2) algebra, revealing a split in electronic dispersion and violation of the Luttinger sum rule, indicating a Mott transition.

## Contribution

It presents a new approach employing su(2|2) algebra to describe strongly correlated electrons and demonstrates a split in electronic dispersion and Luttinger sum rule violation.

## Key findings

- Electronic dispersion splits into two parts.
- Luttinger sum rule is violated.
- Mott metal-insulator transition observed.

## Abstract

We obtain a controlled description of a strongly correlated regime of electronic behaviour. We begin by arguing that there are two ways to characterise the electronic degree of freedom, either by the canonical fermion algebra or the graded Lie algebra su(2|2). The first underlies the Fermi liquid description of correlated matter, and we identify a novel regime governed by the latter. We exploit an exceptional central extension of su(2|2) to employ a perturbative scheme recently developed by Shastry, and obtain a series of successive approximations for the electronic Green's function. We then focus on the leading approximation, which reveals a splitting in two of the electronic dispersion. The Luttinger sum rule is violated, and a Mott metal-insulator transition is exhibited. We offer a perspective.