Curator's Take
This article introduces a two‑mode coherent‑superposed state generated by the operator \(t\,a b+r\,a^{\dagger}b^{\dagger}\) acting on a product of coherent states, and shows that its engineered non‑Gaussianity can lift continuous‑variable teleportation fidelities above the classical limit. By quantifying Wigner negativity and linking it to teleportation performance, the work provides a concrete example of how adding photon‑pair creation to Gaussian resources can yield operational advantages—a theme echoed in recent experiments seeking non‑Gaussian entanglement for quantum networking. The identified parameter regimes give experimentalists clear targets for boosting fidelity with modest resource overhead, although implementing the superposition operator in optics remains a technical hurdle.
— Mark Eatherly
Summary
Glauber's coherent state is denoted by $\ketα$ and its two-mode extension is represented by $\ket{α,β}$. In this work, we introduce a two-mode superposition operator $A=tab+ra^\dagger b^\dagger$, whose action on the two-mode coherent state produces the two-mode coherent superposed quantum state $\ketψ=(tab+ra^\dagger b^\dagger)\ket{α,β}$. We investigate the nonclassicality and quantum non-Gaussianity of this state by means of the Wigner distribution and Wigner logarithmic negativity. Once its intrinsic nonclassical and non-Gaussian structure is established, the state is employed as the entangled resource in the Braunstein-Kimble continuous-variable (CV) teleportation protocol. We compute the ideal teleportation fidelity for coherent and squeezed inputs and analyze how the strengths of nonclassicality and non-Gaussianity influence the teleportation efficiency. Our results identify specific parameter regimes where enhanced non-Gaussian features or increased nonclassicality enable fidelities beyond the classical threshold, thereby revealing the operational significance of engineered two-mode quantum states in CV quantum information processing.