Zero dimensional area law in a gapless fermion system

TL;DR

This paper investigates how weak links in a gapless fermion system contribute to entanglement entropy, revealing a logarithmic dependence on subsystem size.

Contribution

It introduces a numerical analysis showing each weak link adds a lnL term to entanglement entropy in gapless fermion systems.

Findings

Each weak link contributes entropy proportional to lnL.

The entanglement entropy exhibits a zero-dimensional area law.

Numerical evidence supports the logarithmic scaling with system size.

Abstract

The entanglement entropy of a gapless fermion subsystem coupled to a gapless bulk by a "weak link" is considered. It is demonstrated numerically that each independent weak link contributes an entropy proportional to lnL, where L is linear dimension of the subsystem.