An Invisible Quantum Tripwire

TL;DR

This paper introduces a quantum tripwire that uses interaction-free measurement and the quantum Zeno effect to detect intrusions with minimal risk of detection, robustness against loss, and low false alarm rates.

Contribution

It combines interaction-free measurement with a novel nonlinear quantum Zeno effect in lossy systems to create a robust, low-profile quantum intrusion detection scheme.

Findings

Effective detection with low false positives and negatives

Robustness against photon loss and dephasing

Utilizes a new nonlinear quantum Zeno effect in lossy environments

Abstract

We present here a quantum tripwire, which is a quantum optical interrogation technique capable of detecting an intrusion with very low probability of the tripwire being revealed to the intruder. Our scheme combines interaction-free measurement with the quantum Zeno effect in order to interrogate the presence of the intruder without interaction. The tripwire exploits a curious nonlinear behaviour of the quantum Zeno effect we discovered, which occurs in a lossy system. We also employ a statistical hypothesis testing protocol, allowing us to calculate a confidence level of interaction-free measurement after a given number of trials. As a result, our quantum intruder alert system is robust against photon loss and dephasing under realistic atmospheric conditions and its design minimizes the probabilities of false positives and false negatives as well as the probability of becoming visible to the intruder.