Secure continuous variable quantum teleportation and Einstein-Podolsky-Rosen steering

TL;DR

This paper explores the resources and conditions necessary for secure continuous variable quantum teleportation, highlighting the role of Gaussian steerability and proposing practical methods for high-fidelity teleportation.

Contribution

It extends continuous variable teleportation protocols to include quantum tele-amplification and establishes a link between Gaussian steerability and secure teleportation.

Findings

Two-way steering is necessary for fidelity beyond the no-cloning limit.

Heralded noiseless pre-amplification can enable high-fidelity teleportation.

Minimal entanglement with steerability suffices for secure teleportation.

Abstract

We investigate the resources needed for secure teleportation of coherent states. We extend continuous variable teleportation to include quantum tele-amplification protocols, that allow non-unity classical gains and a pre-amplification or post-attenuation of the coherent state. We show that, for arbitrary Gaussian protocols and a significant class of Gaussian resources, two-way steering is required to achieve a teleportation fidelity beyond the no-cloning threshold. This provides an operational connection between Gaussian steerability and secure teleportation. We present practical recipes suggesting that heralded noiseless pre-amplification may enable high-fidelity heralded teleportation, using minimally entangled yet steerable resources.