Application of entanglement conditions to spin systems

TL;DR

This paper introduces new entanglement conditions for blocks of spins in spin systems, demonstrating improved detection of entanglement over traditional methods focused on individual spins, with applications to spin wave states at various temperatures.

Contribution

It presents novel conditions for detecting entanglement in blocks of spins, enhancing the ability to identify entanglement in complex spin states.

Findings

Conditions can detect entanglement better than single-spin criteria.

Effective in spin wave states with few magnons.

Applicable at finite temperatures.

Abstract

There have been numerous studies of entanglement in spin systems. These have usually focussed on examining the entanglement between individual spins or determining whether the state of the system is completely separable. Here we present conditions that allow us to determine whether blocks of spins are entangled. We show that sometimes these conditions can detect entanglement better than conditions involving individual spins. We apply these conditions to study entanglement in spin wave states, both when there are only a few magnons present and also at finite temperature.