Photonic quantum walks with symmetry protected topological phases

We experimentally study the effect of the lattice topology on photonic quantum walks. We generate correlated photon pairs in an array of silicon nanowaveguides making use of the high-nonlinearity available in the system. By using single-photon measurements and propagation simulations we demonstrate the transition between the characteristic path entanglement in random quantum walks and topological localization of the quantum states. Further, we show that this topological localization is robust against disorder that preserves the chiral symmetry of the system.