Multipartite quantum and classical correlations in symmetric n-qubit mixed states

TL;DR

This paper presents a method to efficiently compute genuine multipartite quantum and classical correlations in symmetric n-qubit mixed states, leveraging symmetries to simplify calculations and analyze quantum features in thermodynamic and noisy systems.

Contribution

It introduces a symmetry-based approach to calculate multipartite correlations, reducing computational complexity and enabling analysis of quantum features in various physical scenarios.

Findings

Symmetries significantly reduce optimization parameters in correlation calculations.

The method effectively analyzes quantum correlations in thermodynamic protocols.

It characterizes quantum features in states affected by spatially homogeneous noise.

Abstract

We discuss how to calculate genuine multipartite quantum and classical correlations in symmetric, spatially invariant, mixed $n$-qubit density matrices. We show that the existence of symmetries greatly reduces the amount of free parameters to be optimized in order to find the optimal measurement that minimizes the conditional entropy in the discord calculation. We apply this approach to the states exhibited dynamically during a thermodynamic protocol to extract maximum work. We also apply the symmetry criterion to a wide class of physically relevant cases of spatially homogeneous noise over multipartite entangled states. Exploiting symmetries we are able to calculate the nonlocal and genuine quantum features of these states and note some interesting properties.