Many quantum mechanics — as some like to call themselves — agree.

“D-Wave is misleading the public by calling their device ‘a practical quantum computer,’ ” said Umesh Vazirani, a computer science professor at the University of California, Berkeley. “The whole point of quantum computing is achieving a large speedup over classical computers, something that D-Wave hasn’t accomplished.”

Dr. Rose dismissed such criticism. He characterized D-Wave’s approach as bluntly commercial: he expects the marketplace to endorse Orion and doesn’t care about evaluations in peer-reviewed journals.

“Our approach is to have it start solving problems; how fast it does that becomes the metric by which you’re judged,” he said. “Compared to the academic approaches, ours is quick and dirty, although I don’t think it’s any less careful.”

The high emotions inspired by the D-Wave controversy derive, perhaps, from the almost metaphysical allure of the field, an allure that has existed since the physicists Paul Benioff and Richard P. Feynman proposed the idea of quantum computing in the early 1980s.

In theory, a quantum computer in less than a minute could solve problems that would take millennia for a classical computer to solve.

For instance, a practical quantum computer could easily factor large integers, allowing them to break most cryptographic systems. A quantum computer could also simulate the behavior of nanosized structures like drug molecules; such “quantum simulations” would mean that biotechnologists could model drugs outside of a laboratory, potentially helping them to develop new therapies.

Dr. Rose is not shy about making even grander assertions. He said he believes that a bigger and better Orion computer could also speedily provide optimal solutions to difficult problems with many variables, potentially reshaping such diverse activities as investment, scheduling, logistics, and supply chain management. (Most computer scientists are more cautious: they say the dramatic speedups that Dr. Rose dreams of may be impossible with any quantum computer with a design similar to the Orion.)