Curator's Take
AI Commentary
This article demonstrates a practical route to non‑local multi‑photon interference by swapping optical modes rather than bringing photons together on a single beam splitter, thereby creating entanglement between distant interferometers. The technique extends the classic Hong‑Ou‑Mandel effect into a distributed setting, aligning with recent efforts to build scalable quantum networks where nodes must share multipartite correlations without direct physical overlap. By enabling interference across spatially separated channels, it opens new possibilities for multi‑party protocols such as secret sharing and distributed sensing, though experimental implementation will still need low‑loss mode conversion and precise timing control.
— Mark Eatherly
Summary
Multi-photon interference can be observed using independently generated photons as input. In the most simple case, these photons meet up at a beam splitter, resulting in quantum interference between transmission and reflection of the photons. Here, we show that non-local multi-photon interference can be implemented by using a mode swap operation to generate entanglement between the photons detected in the outputs of two spatially separated interferometers. The spatial separation of the output photons makes this implementation of multi-photon interference particularly suitable for quantum protocols that distribute quantum information to different parties.