We present the experimental generation of tunable entanglement between distinct field modes by the delocalized addition of a single photon. We show that one can preserve a high degree of entanglement even between macroscopically populated modes and illustrate this concept by adding a single photon to two modes containing identical coherent states of growing amplitude. Discorrelation, a new joint statistical property of multimode quantum states, is also experimentally demonstrated here for the first time.
@article{arxiv.1811.10466,
title = {Entangling macroscopic light states by delocalized photon addition},
author = {Nicola Biagi and Luca S. Costanzo and Marco Bellini and Alessandro Zavatta},
journal= {arXiv preprint arXiv:1811.10466},
year = {2025}
}