A new class of quantum effects from interacting photons

Researchers Bankim Chandra Das, Dmytro Kiselov, Lee Drori, Ariel Nakav, Alexander Poddubny and Ofer Firstenberg detail a theoretical study, published October 2, 2026, revealing a multiband dispersion governing the spatial evolution of interacting photons realized through co-propagating Rydberg polaritons. This departs from existing models that typically rely on a single-band, parabolic approximation for these interactions. The work predicts warped vortex structures of photons resulting from interaction-induced symmetry reduction, advancing understanding of multiphoton interactions and supporting the development of future multiphoton control tools. These findings connect quantum nonlinear optics with concepts from multiband and topological quantum matter. The spatial evolution of multiple photons interacting as Rydberg polaritons is governed by a dispersion unlike those previously used to model these systems, featuring both massive and massless modes with degenerate Dirac points. This multiband dispersion departs from the standard single-band, parabolic approximation typically applied to interacting polaritons, offering a more accurate description of their behavior within atomic media. Rigorous numerical modeling confirms…