# Quantum Correlations and Global Coherence in Distributed Quantum Computing

## TL;DR

This paper explores how quantum correlations beyond entanglement and discord, characterized by global coherence, enable enhanced distributed quantum computing capabilities, highlighting their operational significance.

## Contribution

It introduces a new framework for understanding quantum correlations through global coherence, extending beyond entanglement and discord, with operational implications for distributed quantum computing.

## Key findings

- Quantum correlations can be characterized by global coherence resources.
- Entanglement and discord are special cases within this framework.
- Distant parties can increase local quantum resources using these correlations.

## Abstract

Deviations from classical physics when distant quantum systems become correlated are interesting both fundamentally and operationally. There exist situations where the correlations enable collaborative tasks that are impossible within the classical formalism. Here, we consider the efficiency of quantum computation protocols compared to classical ones as a benchmark for separating quantum and classical resources and argue that the computational advantage of collaborative quantum protocols in the discrete variable domain implies the nonclassicality of correlations. By analysing a toy model, it turns out that this argument implies the existence of quantum correlations distinct from entanglement and discord. We characterize such quantum correlations in terms of the net global coherence resources inherent within quantum states and show that entanglement and discord can be understood as special cases of our general framework. Finally, we provide an operational interpretation of such correlations as those allowing two distant parties to increase their respective local quantum computational resources only using locally incoherent operations and classical communication.