Since the Canadian company D-Wave began selling so-called quantum processors, experts have debated whether they're truly quantum. Now, according to an analysis by academic physicists they really do show quantum effects, making them the world's first commercial quantum processors.
In general, it's been difficult to confirm how D-Wave machines work because quantum states are so sensitive, measuring them may perturb them. Besides this new test, performed at the University of Southern California, a few different recent tests have gathered evidence that D-Wave processors work as advertised.
Quantum processors have quantum bits instead of the usual binary bits that traditional processors have. You know normal bits store information by taking on one of two states, often named "0" and "1." Quantum bits, also called qubits, have another capability. They are able to take on both the 0 and 1 states at the same time. This and other properties of quantum states allow quantum computers to perform certain calculations much faster than traditional ones. Quantum processors are generally put to work on optimization problems, such as finding the lowest-energy shape for a protein.
Working on a D-Wave processor Lockheed Martin bought, the USC researchers put eight of the D-Wave's 128 qubits to work on an optimization problem. They found that the procedure that the D-Wave used was consistent with quantum annealing--the process that D-Wave's creators say it uses--instead of classical annealing, one of the researchers, Daniel Lidar, said in a statement.
Physicists and computational scientists still debate how practical a D-Wave could be. Nevertheless, a few institutions have bought D-Wave machines, including Lockheed Martin, Google, NASA and the Universities Space Research Association.
Lidar and his colleagues published their work in the journal Nature Communications.