On-chip interaction-free measurements via the quantum Zeno effect

TL;DR

This paper demonstrates an on-chip, high-efficiency interaction-free measurement using the quantum Zeno effect in silicon photonics, achieving near-perfect interference stability and surpassing previous efficiency limits.

Contribution

It presents the first on-chip implementation of interaction-free measurement leveraging the quantum Zeno effect with high visibility and efficiency.

Findings

Interference visibility above 98% in silicon photonics.

Normalized IFM efficiency up to 68.2%.

Surpassed the 50% efficiency limit of original IFM proposals.

Abstract

Although interference is a classical-wave phenomenon, the superposition principle, which underlies interference of individual particles, is at the heart of quantum physics. An interaction-free measurements (IFM) harnesses the wave-particle duality of single photons to sense the presence of an object via the modification of the interference pattern, which can be accomplished even if the photon and the object haven't interacted with each other. By using the quantum Zeno effect, the efficiency of an IFM can be made arbitrarily close to unity. Here we report an on-chip realization of the IFM based on silicon photonics. We exploit the inherent advantages of the lithographically written waveguides: excellent interferometric phase stability and mode matching, and obtain multipath interference with visibility above 98%. We achieved a normalized IFM efficiency up to 68.2%, which exceeds the 50% limit of the original IFM proposal.