Quantifying quantum correlation of quasi-Werner state and probing its suitability for quantum teleportation

TL;DR

This paper investigates how photon addition affects the nonclassicality and quantum correlations of quasi-Werner states, demonstrating improved quantum teleportation fidelity and challenging the use of Wigner negativity as a quantum correlation witness.

Contribution

It introduces a theoretical analysis of photon-added bipartite states, quantifies nonclassicality and correlations, and shows enhanced teleportation performance with photon addition.

Findings

Photon addition enhances nonclassicality and quantum correlations.

Teleportation fidelity improves with photon addition.

Negative Wigner function values are not reliable quantum correlation witnesses.

Abstract

The significance of photon addition in engineering the single- and two-mode (bipartite correlations) nonclassical properties of a quantum state is investigated. Specifically, we analyzed the behavior of the Wigner function of two quasi-Werner states theoretically constructed by superposing two normalized bipartite $m$-photon added coherent states. This allowed us to quantify the amount of nonclassicality present in the quantum states using Wigner logarithmic negativity (WLN), while quantum correlations are measured in terms of concurrence, entanglement of formation, and quantum discord. The WLN for a two-mode state corresponds to the sum of the single-mode nonclassicality as well as quantum correlations, and both of these are observed to enhance with photon addition manifesting the efficacy of photon addition in the entanglement distillation. Usefulness of photon addition is further established by showing that the performance of the quasi-Werner states as quantum channel for the teleportation of a single-mode coherent and squeezed states, as quantified via teleportation fidelity, improves with the photon addition. Further, in contrast to a set of existing results, it is established that the negative values of two-mode Wigner function cannot be used in general as a witness of quantum correlation.