Entanglement Entropies of Non-Equilibrium Finite-Spin Systems

TL;DR

This paper introduces a thermofield dynamics approach to analyze entanglement entropies in non-equilibrium finite-spin systems, deriving an extended entropy measure and demonstrating its effectiveness in identifying maximally entangled states.

Contribution

It presents a novel TFD-based method for calculating and understanding entanglement entropies in non-equilibrium quantum spin systems, including the derivation of an extended entropy measure.

Findings

Extended entanglement entropy $\,\hat{S}$ derived.

Conditions for maximum entanglement identified.

Method effectively distinguishes quantum states.

Abstract

For the purpose of clarifying a new approach to understanding quantum entanglement using thermofield dynamics (TFD), entanglement entropies of non-equilibrium finite-spin systems are examined for both traditional and extended cases. The extended entanglement entropy, $\hat{S}$, is derived, and it is found that the conditions for the maximum entangled state can be obtained through this approach. The capacity of the TFD-based method to distinguish between states in quantum systems is confirmed.