Spanning Tree Calculations on D-Wave 2 Machines

Calculations on D-Wave machines are presented, both for the 500-qubit and the 1000-qubit machines. Results are presented for spanning trees on the available K-4,K-4 Chimera graphs of both machines. Comparing trees of approximately the same size, the frequency of finding the ground state for the 1000-qubit machine is significantly improved over the 500-qubit older generation machine. Spanning trees are difficult problems for solution by adiabatic quantum computers, so the enhanced frequency of finding the ground state for newer machine generations and larger machines is encouraging for this immature technology.