Singularity in Entanglement Negativity Across Finite Temperature Phase Transitions

TL;DR

This paper investigates how entanglement negativity, a quantum correlation measure, exhibits singular behavior at finite temperature phase transitions in exactly solvable models, highlighting quantum effects in thermal phase changes.

Contribution

It demonstrates that entanglement negativity shows singularity at finite temperature phase transitions, providing a quantum signature absent in classical correlations.

Findings

Entanglement negativity is singular across finite temperature phase transitions.

Exact calculations of entanglement of formation in a related model.

Quantum correlations can signal phase transitions at finite temperature.

Abstract

Phase transitions at a finite (i.e. non-zero) temperature are typically dominated by classical correlations, in contrast to zero temperature transitions where quantum mechanics plays an essential role. Therefore, it is natural to ask if there are any signatures of a finite temperature phase transition in measures that are sensitive only to quantum correlations. Here we study one such measure, namely, entanglement negativity, across finite temperature phase transitions in several exactly solvable Hamiltonians and find that it is a singular function of temperature across the transition. As an aside, we also calculate the entanglement of formation exactly in a related, interacting model.