Local Quantum Uncertainty in Two-Qubit Separable States: A Case Study

TL;DR

This paper investigates the local quantum uncertainty in two-qubit separable states, revealing states with maximum uncertainty and their relation to other quantum correlations like discord.

Contribution

It identifies separable X-states with maximum local quantum uncertainty and explores their connection to geometric discord and entropic uncertainty.

Findings

Separable X-states can have maximum local quantum uncertainty.

Maximum local quantum uncertainty coincides with maximum geometric discord.

Connection between local quantum uncertainty and entropic uncertainty is established.

Abstract

Recent findings suggest, separable states, which are otherwise of no use in entanglement dependent tasks, can also be used in information processing tasks that depend upon the discord type general non classical correlations. In this work, we explore the nature of uncertainty in separable states as measured by local quantum uncertainty. Particularly in two-qubit system, we find separable X-state which has maximum local quantum uncertainty. Interestingly, this separable state coincides with the separable state, having maximum geometric discord. We also search for the maximum amount of local quantum uncertainty in separable Bell diagonal states. We indicate an interesting connection to the tightness of entropic uncertainty with the state of maximum uncertainty.