Highly Entangled Ground States in Tripartite Qubit Systems

TL;DR

This paper explores how to generate and optimize highly entangled ground states in a system of three exchange-coupled qubits arranged in a ring, using magnetic fields and a novel optimization algorithm.

Contribution

It introduces a method to identify magnetic field configurations for creating GHZ and W ground states and efficiently evaluates entanglement at finite temperatures.

Findings

Optimal magnetic field parameters for maximum entanglement identified

Efficient evaluation of mixed-state tangle tau demonstrated

Ground states with high entanglement achievable in tripartite qubit systems

Abstract

We investigate the creation of highly entangled ground states in a system of three exchange-coupled qubits arranged in a ring geometry. Suitable magnetic field configurations yielding approximate GHZ and exact W ground states are identified. The entanglement in the system is studied at finite temperature in terms of the mixed-state tangle tau. By adapting a steepest-descent optimization algorithm we demonstrate that tau can be evaluated efficiently and with high precision. We identify the parameter regime for which the equilibrium entanglement of the tripartite system reaches its maximum.