Zhang, ZheFleury, Romain2025-05-222025-05-222025-05-222025-0510.1038/s41566-025-01664-7https://infoscience.epfl.ch/handle/20.500.14299/250401Topological localization of photons in both space and time has now been experimentally realized through synthetic photonic quantum walks, enabled by non-Hermitian gain–loss modulations. This investigation into time and space-time topology reveals unique phenomena beyond conventional spatial topological effects, including causality-suppressed coupling.entext::journal::journal article::review article