Quantum computing is such an elusive goal that even the company claiming to have the "world's first commercial quantum computer" acknowledged it isn't entirely sure the machine is performing true quantum calculations.
And independent quantum computing researchers said they are dubious of some of the claims made by D-Wave Systems Inc. because the privately held Canadian company has not yet submitted its findings for peer review, a standard step for gaining acceptance in scientific circles.
Many scientists believe that true quantum computing — which is based on the unusual properties of quantum physics — promises to solve certain factoring, simulation and other intensive problems faster than today's machines that rely on classical physics. Most say it's likely still years or decades away.
"Until we see more actual measurements, it's hard to know whether they succeeded or not," said Phil Kuekes, a computer architect in the Quantum Science Research Group at Hewlett-Packard Co.'s HP Labs.
D-Wave held its first public demonstration Tuesday of a machine it claims uses quantum mechanics to solve a certain type of problems, such as searching a database for matching molecular structures.
But the company did not make the machine available for inspection and instead showed video from a remote location, saying it was too sensitive to be easily transported.
And notwithstanding lofty claims in the company's press release about creating the world's first commercial quantum computer, D-Wave Chief Executive Herb Martin emphasized that the machine is not a true quantum computer and is instead a kind of special-purpose machine that uses some quantum mechanics to solve problems.
"Users don't care about quantum computing — users care about application acceleration. That's our thrust," he said. "A general purpose quantum computer is a waste of time. You could spend hundreds of billions of dollars on it" and not create a working computer.
He said all the evidence the company has indicates that the device is performing quantum computations, but he acknowledged there is some uncertainty. He also said the company could encounter problems in maintaining quantum functions as the machine is made more powerful.
The machine currently runs at 16 qubits, the basic unit of quantum computing. That's less power than most standard computers and what the company calls a proof of concept.
Martin said the company plans to have it running at about 1,000 qubits by the time the product goes on sale next year.
A unique characteristic of quantum computing is that, unlike digital bits that can only have values of 0 or 1, qubits can exist in states 0 and 1 at the same time and promises to allow the machine to tap into a vast pool of computational power.