Experiments with the DWave prototype

Sergio Boixo

Google

Quantum annealing is an optimization method designed to take advantage of quantum phenomena, such as quantum superposition, tunneling and quantum fluctuations. Diabatic transactions between energy levels, and thermal excitations and relaxation, can play an important role in quantum annealing (as opposed to adiabatic quantum computation). DWave

has implemented a physical quantum annealing prototype with up to 512 qubits. The decoherence time scale in this device is much shorter than the annealing time. I will review recent work done in this prototype. On the one hand, we find evidence of entanglement within eight superconducting flux qubits. On the other hand, we find no evidence of a quantum speedup for the case of random Ising glasses when the entire data set is considered, and obtain inconclusive results when comparing subsets of problems on an instance-by-instance basis. I will present preliminary new results and theory comparing noisy quantum annealing, the DWave prototype, and several numerical models.