Measurement-Device-Independent Entanglement Witnesses for All Entangled Quantum States

TL;DR

This paper introduces measurement-device-independent entanglement witnesses (MDI-EWs) that can verify entanglement in all entangled states without trusting measurement devices, enhancing robustness and practical implementation in quantum information processing.

Contribution

The paper presents a systematic method to derive MDI-EWs from standard witnesses, enabling entanglement verification with untrusted measurement devices for all entangled states.

Findings

MDI-EWs can verify all entangled states.

The construction is loss-tolerant and experimentally feasible.

Method allows for device-independent entanglement certification.

Abstract

The problem of demonstrating entanglement is central to quantum information processing applications. Resorting to standard entanglement witnesses requires one to perfectly trust the implementation of the measurements to be performed on the entangled state, which may be an unjustified assumption. Inspired by the recent work of F. Buscemi [Phys. Rev. Lett. 108, 200401 (2012)], we introduce the concept of Measurement-Device-Independent Entanglement Witnesses (MDI-EWs), which allow one to demonstrate entanglement of all entangled quantum states with untrusted measurement apparatuses. We show how to systematically obtain such MDI-EWs from standard entanglement witnesses. Our construction leads to MDI-EWs that are loss-tolerant, and can be implemented with current technology.