Conclusive experimental demonstration of one-way Einstein-Podolsky-Rosen steering

TL;DR

This paper reports the first experimental demonstration of one-way Einstein-Podolsky-Rosen steering without restrictive assumptions, utilizing a new non-steerability condition and high-quality photonic Werner states.

Contribution

It introduces an assumption-free experimental demonstration of one-way EPR steering, advancing the understanding of quantum nonlocality.

Findings

First assumption-free demonstration of one-way steering.

Utilized a new sufficient condition for non-steerability.

Produced high-quality photonic Werner states.

Abstract

Einstein-Podolsky-Rosen steering is a quantum phenomenon wherein one party influences, or steers, the state of a distant party's particle beyond what could be achieved with a separable state, by making measurements on one half of an entangled state. This type of quantum nonlocality stands out through its asymmetric setting, and even allows for cases where one party can steer the other, but where the reverse is not true. A series of experiments have demonstrated one-way steering in the past, but all were based on significant limiting assumptions. These consisted either of restrictions on the type of allowed measurements, or of assumptions about the quantum state at hand, by mapping to a specific family of states and analysing the ideal target state rather than the real experimental state. Here, we present the first experimental demonstration of one-way steering free of such assumptions. We achieve this using a new sufficient condition for non-steerability, and, although not required by our analysis, using a novel source of extremely high-quality photonic Werner states.