Quantum hopping of frequency-bin entangled photon pairs

Quantum walks of entangled particles have promising applications in simulating many-body physics, as well as in implementing quantum search algorithms. Here, we report continuous quantum walks of a two-photon quantum frequency comb using electro-optic phase modulation to tune the evolution of the state through the quantum circuit. By manipulating the spectral phase of the initial entangled state, we demonstrate either enhanced ballistic energy transport or energy bound states, which are signatures of bosonic and fermionic frequency hopping, respectively. In addition, applying quadratic spectral phase on the initial state creates different subspaces featuring bosonic or fermionic character. We also explore the effect of increasing entanglement dimensionality in frequency domain quantum hopping; our results suggest the potential of our circuit for certifying high-dimensional entanglement.