Non-Gaussian entangled states and quantum teleportation of Schr\"odinger-cat states

TL;DR

This paper explores how non-Gaussian entangled states, created by photon subtraction from Gaussian states, enhance quantum teleportation of Schr"odinger-cat states by improving fidelity and enabling negativity in the Wigner function.

Contribution

It demonstrates that non-Gaussian entangled resources reduce the squeezing needed for effective teleportation of non-classical states.

Findings

Non-Gaussian entangled states improve teleportation fidelity.

Photon subtraction enhances entanglement in Gaussian states.

Lower squeezing levels are sufficient for high-quality teleportation.

Abstract

In continuous-variable quantum information, non-Gaussian entangled states that are obtained from Gaussian entangled states via photon subtraction are known to contain more entanglement. This makes them better resources for quantum information processing protocols, such as, quantum teleportation. We discuss the teleportation of non-Gaussian, non-classical Schr\"odinger-cat states of light using two-mode squeezed vacuum light that is made non-Gaussian via subtraction of a photon from each of the two modes. We consider the experimentally realizable cat states produced by subtracting a photon from the single-mode squeezed vacuum state. We discuss two figures of merit for the teleportation process, a) the fidelity, and b) the maximum negativity of the Wigner function at the output. We elucidate how the non-Gaussian entangled resource lowers the requirements on the amount of squeezing necessary to achieve any given fidelity of teleportation, or to achieve negative values of the Wigner function at the output.