Kronecker graphs, obtained by repeatedly performing the Kronecker product of the adjacency matrix of an “initiator” graph with itself, have risen in popularity in network science due to their ability to generate complex networks with real-world properties. We explore spatial search by continuous-time quantum walk on Kronecker graphs. Specifically, we give analytical proofs for quantum search on first-, second-, and third-order Kronecker graphs with the complete graph as the initiator, showing that search takes Grover's $O\left(\sqrt{N}\right)$ time. Numerical simulations indicate that higher-order Kronecker graphs with the complete initiator also support optimal quantum search.

• Received 30 April 2018

DOI:https://doi.org/10.1103/PhysRevA.98.012338