Quantum indistinguishability by path identity and with undetected photons
Armin Hochrainer, Mayukh Lahiri, Manuel Erhard, Mario Krenn, Anton Zeilinger · Reviews of Modern Physics · 2022
The double-slit experiment manifests the duality between wave interference and the distinguishability of paths taken by a particle though an apparatus. This article reviews advanced developments of these concepts with pairs of particles, starting with experiments on quantum foundations with photon pairs in the 1990s. These experiments now form the basis for applications in quantum information as well as for spatial imaging and spectroscopy that is performed without ever detecting the photons that interacted with the object.