Quantum effects are indeed at play in the world's first commercial quantum optimization processor manufactured by the company D-Wave, according to scientists at the University of Southern California.
The team demonstrated that the processor housed at the USC-Lockheed Martin Quantum Computing Center behaves in a way that indicates quantum mechanics has a functional role in the way it works. What this means is that the device appears to be operating as a quantum processor - something the company has long claimed but has been at the subject of much debate.
Purchased by Lockheed Martin nearly two years ago, the processor is housed at the univeristy's Informational Sciences Institute (ISI) and, as the first of its kind, scientists had to determine whether the quantum computer was operating as hoped before weighing in decisively.
"Using a specific test problem involving eight qubits, we have verified that the D-Wave processor performs optimization calculations using a procedure that is consistent with quantum annealing and is inconsistent with the predictions of classical annealing," Daniel Lidar, scientific director of the Quantum Computing Center and one of the team researchers, said in a press release.
Quantum bits, or qubits, are considered the basic building blocks of quantum computers. Quantum annealing, on the other hand, is a method of solving optimization problems using quantum mechanics and, at a large enough scale, could potentially be much faster than a traditional processor.
Qubits have the capability of encoding the two digits of one and zero at the same time - a property called superposition that, along with the ability of quantum states to "tunnel" through energy barriers, are hoped to play a role in helping future generations of the D-Wave processors perform optimization calculations far faster than today's technology.
In May, Amherst College's Catherin McGeogh devised and conducted experiments to test the speed of the D-Wave system, reporting in a statement that, in some cases, it is "really, really fast."
"You think you're in Dr. Seuss land," she said. "It's such a whole different approach to computation that you have to wrap your head around this new way of doing things in order to decide how to evaluate it. It's like comparing apples and oranges, or apples and fish, and the difficulty was coming up with experiments and analyses that allowed you to say you'd compared things properly."
She did not, however, weigh in on whether or not the machine is quantum-based.
The USC team's research, however, showed that the system and the chip it runs on behaved as hope, ultimately avoiding the trap of decoherence, which quantum processors can fall victim to.
"Our work seems to show that, from a purely physical point of view, quantum effects play a functional role in information processing in the D-Wave processor," concluded Sergio Boixo, first author of the paper who conducted the research while he was a computer scientist at ISI.
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