Entanglement area law from specific heat capacity

TL;DR

This paper establishes conditions under which low-energy states of quantum many-body systems obey an entanglement area law, linking thermodynamic properties like specific heat capacity decay to entanglement scaling.

Contribution

It provides the first proof of an area law for unbounded Hamiltonians and connects heat capacity decay rates to entanglement scaling in low-energy states.

Findings

Exponential decay of specific heat implies an area law for entanglement.

Polynomial decay of specific heat leads to subvolume entanglement scaling.

Results are experimentally verifiable and apply to non-integrable systems.

Abstract

We study the scaling of entanglement in low-energy states of quantum many-body models on lattices of arbitrary dimensions. We allow for unbounded Hamiltonians such that systems with bosonic degrees of freedom are included. We show that if at low enough temperatures the specific heat capacity of the model decays exponentially with inverse temperature, the entanglement in every low-energy state satisfies an area law (with a logarithmic correction). This behaviour of the heat capacity is typically observed in gapped systems. Assuming merely that the low-temperature specific heat decays polynomially with temperature, we find a subvolume scaling of entanglement. Our results give experimentally verifiable conditions for area laws, show that they are a generic property of low-energy states of matter, and, to the best of our knowledge, constitute the first proof of an area law for unbounded Hamiltonians beyond those that are integrable.