Subdiffusive dynamics in photonic random walks probed with classical light

Abstract: The random walk of photons in a tight-binding lattice is known to exhibit diffusive motion similar to classical random walks under decoherence, clearly illustrating the quantum-to-classical transition. In this study, we reveal that the random walk of intense classical light under dephasing dynamics can disentangle quantum and ensemble averaging, making it possible to observe a subdiffusive walker dynamics, i.e. a behavior very distinct from both a classical and a quantum walker. These findings are demonstrated through proposing photonic random walks in synthetic temporal lattices, based on pulse dynamics in coupled fiber loops.