Quantum computer from D-Wave no faster than traditional in new tests

Science : D-Wave markets its computer as a “quantum annealer ” that uses quantum tunneling to find solutions by finding the ground state for its quantum bits. If it is a truly quantum computer, it should be expected to outperform classical computers in many sorts of calculations. Now Matthias Troyer of ETH-Zürich and his colleagues have put D-Wave’s computer to its first real test. They timed how long the machine took to reach ground state for increasing levels of complexity (measured by the number of qubits set to a random energy level) and compared those times with a classical computer simulating a thermal annealing process, which does not have the speed benefit that quantum tunneling would provide. The results showed no difference between the two machines in increase in time needed for more complex problems. Colin Williams, D-Wave’s director of business development, says that the comparison was not an appropriate technique for measuring the quantum speedup.