Quantum Discord for multiqubit Systems

TL;DR

This paper analytically evaluates quantum discord in multiqubit states, revealing patterns, categories, and dynamic behaviors under decoherence, with differences between odd and even qubit systems.

Contribution

It provides an analytical evaluation of quantum discord for multiqubit states, identifying categories and dynamic behaviors under decoherence, including the absence of frozen discord in odd systems.

Findings

Quantum discord is the same for three- and five-qubits, and for two- and six-qubits.

Quantum discord can be categorized into three distinct groups.

Frozen quantum discord occurs in even but not in odd partite systems under phase flip channels.

Abstract

We evaluate analytically the quantum discord for a large family of multiqubit states. It is interesting to note that the quantum discord of three-qubits and five-qubits is the same, as is the quantum discord of two-qubits and six-qubits. We discover that the quantum discord of this family states can be concluded into three categories. The level surfaces of the quantum discord in the three categories is shown through images. Furthermore, we investigated the dynamic behavior of quantum discord under decoherence. For the odd partite systems, we prove the frozen phenomenon of quantum discord doesn't exist under the phase flip channel, while it can be found in the even partite systems.