Thermal entanglement in a molecular chain

TL;DR

This paper explores how entanglement in a linear chain of polar molecules is affected by various physical parameters, revealing that only excited states are entangled and that entanglement can be controlled by external fields and temperature.

Contribution

It provides a systematic analysis of entanglement behavior in molecular chains under different conditions, highlighting the effects of electrostatic fields and temperature on entanglement properties.

Findings

Entanglement exists only in excited states.

Electrostatic fields cause energy level crossings affecting entanglement.

Entanglement persists at relatively high temperatures.

Abstract

We investigate entanglement in a linear chain of $N$ polar molecules coupled by dipole interaction. In our model, nearest neighbour interaction predominate, and we compute entanglement with the help of a two-party correlation entanglement measure. We find that, in this system, only excited states are entangled. Moreover, when an electrostatic field is applied, energy levels crossings occur, changing significantly the system's entanglement properties. We make a systematic study of the entanglement dependency on the inter molecular distance separating pairs of molecules, different partitions of the chain and physical parameters as the temperature and the electrostatic field's intensity, showing that it persists for relatively high temperatures and changes its nature with varying field.