Author(s): Elias Charnay, Adrien Escoubet, François Copie, Stéphane Randoux, Thibault Bonnemain, Alvise Bastianello, and Pierre Suret Unequal-time correlation functions fundamentally characterize emergent statistical properties in complex systems, yet their direct measurement in experiments is challenging. We report the experimental observation of two-time, ballistic correlations in a photonic platform governed by the focusing non… [Phys. Rev. Lett. 137, 097202] Published Thu Aug 27, 2026