Macroscopic Multi-Species Entanglement near Quantum Phase Transitions

TL;DR

This paper demonstrates that multi-species entanglement in many-particle systems can be macroscopic, exhibits singular behavior at quantum phase transitions, and can be analytically calculated in models like the 1D Ising model.

Contribution

It introduces the concept of macroscopic multi-species entanglement and shows its ability to detect quantum phase transitions analytically.

Findings

Entanglement exhibits singular behavior near quantum critical points.

First derivative of entanglement shows a jump discontinuity.

Second derivative diverges at the quantum critical point.

Abstract

Multi-Species entanglement, defined for a many-particle system as the entanglement between different species of particles, is shown to exist in the thermodynamic limit of the system size going to infinity. This macroscopic entanglement, as it can exhibit singular behavior, is capable of tracking quantum phase transitions. The entanglement between up and down spins has been analytically calculated for the one-dimensional Ising model in a transverse magnetic field. As the coupling strength is varied, the first derivative of the entanglement shows a jump discontinuity and the second derivative diverges near the quantum critical point.