A simple thermodynamical witness showing universality of macroscopic entanglement

TL;DR

This paper introduces a universal thermodynamical criterion to detect entanglement in physical systems, establishing a temperature threshold below which entanglement is guaranteed, applicable to various many-body systems.

Contribution

It presents a simple, thermodynamical entanglement witness based on ground state entanglement and entropy, applicable across different physical systems.

Findings

Entanglement exceeds entropy in certain conditions, indicating entangled states.

Derived critical temperatures for bosonic and fermionic systems where entanglement is guaranteed.

Universal applicability of the thermodynamical witness across diverse physical systems.

Abstract

We show that if the ground state entanglement exceeds the total entropy of a given system, then this system is in an entangled state. This is a universal entanglement witness that applies to any physical system and yields a temperature below which we are certain to find some entanglement. Our witness is then applied to generic bosonic and fermionic many body systems to derive the corresponding "critical" temperatures that have a very broad validity.