Complementarity in single photon interference - the role of mode functions and vacuum fields

TL;DR

This paper investigates how mode functions and vacuum fields influence single photon interference, demonstrating that vacuum field spatial coherence underpins the complementarity observed in quantum optics experiments.

Contribution

It provides experimental evidence linking vacuum field coherence to the complementarity in single photon interference, highlighting the physical role of vacuum fields.

Findings

Vacuum fields' spatial coherence is measurable.

Vacuum fields are the physical basis for complementarity.

Mode functions influence single photon interference patterns.

Abstract

Single photon first order interferences of spatially separated regions from the cone structure of spontaneous parametric down conversion allow for analyzing the role of the mode function in quantum optics. In earlier experiments the role of the vacuum fields could be demonstrated in induced coherence experiments as the source of complementarity \cite{Heu14}. Here the spatial coherence properties of these vacuum fields are measured and as the physical reason for complementarity in single photon quantum optics demonstrated.