Exploring Quantum Correlations from Discord to Entanglement

TL;DR

This paper experimentally explores the geometry of polarization Bell-diagonal states to analyze quantum correlations like entanglement and discord, revealing phenomena such as sudden death and freezing of correlations with good experimental-theoretical agreement.

Contribution

It provides a novel experimental investigation of the geometry of quantum correlations in Bell-diagonal states, highlighting phenomena like entanglement sudden death and discord freezing.

Findings

Observation of entanglement sudden death

Detection of complete discord freezing

Strong agreement between experimental data and theoretical models

Abstract

Quantum correlations represent a fundamental tool for studies ranging from basic science to quantum technologies. Different non-classical correlations have been identified and studied, as entanglement and discord. In this Paper we explore experimentally the rich geometry of polarization Bell-diagonal states. By taking advantage of the statistical method of generation, the values of entanglement and discord along different trajectories in the space of the parameters of density matrix have been measured. The effects of sudden death of entanglement and complete "freeze" of discord were investigated in order to detect the domains with different domination of one type of quantum correlation against to other. A geometric interpretation for each considered phenomena is addressed. The observed good agreement between experiment and theory for all investigated trajectories ensures the reliability of this method.