Subarea law of entanglement in nodal fermionic systems

TL;DR

This paper studies how entanglement entropy scales in fermionic systems without a finite Fermi surface, revealing different behaviors in gapped, critical, and phase boundary regimes.

Contribution

It characterizes the subarea law scaling of entanglement entropy in nodal fermionic systems, highlighting distinct behaviors across different phases.

Findings

Gapped regimes exhibit a negative constant subarea term.

Critical regimes with point nodes show logarithmic subarea scaling.

At phase boundaries, subarea scaling follows a power-law behavior.

Abstract

We investigate the subarea law scaling properties of the block entropy in bipartite fermionic systems which do not have a finite Fermi surface. It is found that in gapped regimes the leading subarea term is a negative constant, whereas in critical regimes with point nodes the leading subarea law is a logarithmic additive term. At the phase boundary that separates the critical and non-critical regimes, the subarea scaling shows power-law behavior.