Missing data outside the detector range: application to continuous variable entanglement verification and quantum cryptography

TL;DR

This paper examines how finite detector range in continuous-variable quantum information can lead to overestimated entanglement and security, proposing entropic criteria as a better solution than variance-based methods.

Contribution

It introduces the issue of missed data outside detector range and demonstrates that entropic criteria outperform variance-based criteria in mitigating this problem.

Findings

Entropic criteria provide more reliable entanglement verification.

Ignoring data outside detector range can lead to overestimations.

Entropic methods improve security assessments in quantum cryptography.

Abstract

In continuous-variable quantum information processing detectors are necessarily coarse grained and of finite range. We discuss how especially the latter feature is a bug and may easily lead to overoptimistic estimates of entanglement and of security, when missed data outside the detector range are ignored. We show that entropic separability or security criteria are much superior to variance-based criteria for mitigating the negative effects of this bug.