Detecting genuine multipartite entanglement in steering scenarios

TL;DR

This paper introduces new criteria and inequalities for detecting genuine tripartite EPR-steering, a form of quantum nonlocality, in semi-device-independent scenarios, expanding the understanding of quantum correlations.

Contribution

It presents two types of genuine tripartite EPR-steering and derives inequalities to detect them, including scenarios where Charlie's measurements are compatible.

Findings

Violating the inequalities certifies genuine tripartite entanglement.

Quantum correlations can detect tripartite EPR-steering even with compatible measurements.

The work extends EPR-steering detection to semi-device-independent scenarios.

Abstract

Einstein-Podolsky-Rosen (EPR) steering is a form of quantum nonlocality which is intermediate between entanglement and Bell nonlocality. EPR steering is a resource for quantum key distribution that is device independent on only one side in that it certifies bipartite entanglement when one party's device is not characterized while the other party's device is fully characterized. In this work, we introduce two types of genuine tripartite EPR-steering, and derive two steering inequalities to detect them. In a semi-device-independent scenario where only the dimensions of two parties are assumed, the correlations which violate one of these inequalities also certify genuine tripartite entanglement. It is known that Alice can demonstrate bipartite EPR-steering to Bob if and only if her measurement settings are incompatible. We demonstrate that quantum correlations can also detect tripartite EPR-steering from Alice to Bob and Charlie, even if Charlie's measurement settings are compatible.