Generation of quantum discord between ionic qubits via noisy processes

TL;DR

This paper demonstrates how quantum discord can be generated between two trapped ions through noisy, decoherence processes, even without entanglement, highlighting a potential resource for quantum information tasks.

Contribution

It shows that quantum discord can be generated via Markovian decoherence in trapped ions, including from classically correlated or uncorrelated states, expanding understanding of quantum correlations.

Findings

Quantum discord can be generated by decoherence in trapped ions.

Discord can be created from classically correlated states.

Werner states are successfully produced.

Abstract

Quantum systems in mixed states can be unentangled and yet still correlated in a way that is not possible for classical systems. These correlations can be quantified by the quantum discord and might provide a resource for certain mixed-state quantum information processing tasks. Here we report on the generation of discordant states of two trapped atomic ions via Markovian decoherence processes. While entanglement is strictly non-increasing under such operations, discord can be generated in various forms. Firstly we show that, starting from two classically correlated qubits, it is possible to generate discord by applying decoherence to just one of them. Secondly, even when starting with completely uncorrelated systems, we show that discord can be generated via classically correlated decoherence processes. Finally, the Werner states are created. The generated states can be used as a resource state for quantum information transmission and could be readily extended to more ions.