2021/12/13 by Peter Namdar, Philipp K. Jenke, Namdar, Peter +13 · 1 citation
Engineering · Physics and Astronomy · #FOS: Physical sciences #Optical Network Technologies #Orbital Angular Momentum in Optics #Photonic and Optical Devices #Quantum Physics (quant-ph)
paper · pdf · doi:10.48550/arxiv.2112.06965
openalex publication_date 2021/12/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
Interference between two waves is a well-known concept in physics, and its generalization to more than two waves is straight-forward. The order of interference is defined as the number of paths that interfere in a manner that cannot be reduced to patterns of a lower order. In practice, second-order interference means that in, say, a triple-slit experiment, the interference pattern when all three slits are open can be predicted from the interference patterns between all possible pairs of slits. Quantum mechanics is often said to only exhibit second-order interference. However, this is only true under specific assumptions, typically single-particles undergoing linear evolution. Here we experimentally show that nonlinear evolution can in fact lead to higher-order interference. The higher-order interference in our experiment has a simple quantum mechanical description; namely, optical coherent states interacting in a nonlinear medium. Our work shows that nonlinear evolution could open a loophole for experiments attempting to verify Born's rule by ruling out higher-order interference.