Conditional purity and quantum correlation measures in two qubit mixed states

TL;DR

This paper investigates quantum correlations in mixed two-qubit states, providing analytical expressions and experimental verification for measures like quantum discord and conditional purity relevant to quantum information processing.

Contribution

It derives explicit analytical formulas for quantum correlation measures in mixed two-qubit states and experimentally verifies these results, linking theory with practical quantum systems.

Findings

Analytical expressions for conditional purity and quantum discord.

Experimental verification of correlation measures in photon-based two-qubit states.

Relevance of these states to spin chain models in magnetic fields.

Abstract

We analyze and show experimental results of the conditional purity, the quantum discord and other related measures of quantum correlation in mixed two-qubit states constructed from a pair of photons in identical polarization states. The considered states are relevant for the description of spin pair states in interacting spin chains in a transverse magnetic field. We derive clean analytical expressions for the conditional local purity and other correlation measures obtained as a result of a remote local projective measurement, which are fully verified by the experimental results. A simple exact expression for the quantum discord of these states in terms of the maximum conditional purity is also derived.