Thanks. I wasn't familiar with that company until you mentioned them. But since Science News is a fairly reputable scientific source, I figured 'something' wasn't quite kosher here. So I looked it up and found this...
"Their claimed speedup over classical algorithms appears to be based on a misunderstanding of a paper my colleagues van Dam, Mosca and I wrote on "The power of adiabatic quantum computing."
That speed up unfortunately does not hold in the setting at hand, and therefore D-Wave's "quantum computer" even if it turns out to be a true quantum computer, and even if it can be scaled to thousands of qubits, would likely not be more powerful than a cell phone."
Wim van Dam, a professor at UC Santa Barbara, summarized the scientific community consensus as of 2008 in the journal Nature Physics:[55]
″At the moment it is impossible to say if D-Wave's quantum computer is intrinsically equivalent to a classical computer or not.
So until more is known about their error rates, caveat emptor is the least one can say″.
An article in the May 12, 2011 edition of Nature gives details which critical academics say proves that the company's chips do have some of the quantum mechanical properties needed for quantum computing.[56][57]
Prior to the 2011 Nature paper, D-Wave was criticized for lacking proof that its computer was in fact a quantum computer.
Nevertheless, questions were raised[58] and later answered[59] regarding experimental proof of quantum entanglement inside D-Wave devices.
Former MIT professor Scott Aaronson, who has described himself as "Chief D-Wave Skeptic", said that D-Wave's 2007 demonstration did not prove anything about the workings of the Orion computer, and that its marketing claims were deceptive.[60]
In May 2011 he said that he was "retiring as Chief D-Wave Skeptic",[61] and reporting his "skeptical but positive" views based on a visit to D-Wave in February 2012.
Aaronson said that one of the most important reasons for his new position on D-Wave was the 2011 Nature article.[58][62][63]
In May 16, 2013 he resumed his skeptic post.
He criticizes D-Wave for blowing results out of proportion on press releases that claim speedups of three orders of magnitude, in light of a paper[38] by scientists from ETH Zurich reporting a 128-qubit D-Wave computer being outperformed by a factor of 15 using regular digital computers and applying classical metaheuristics (particularly simulated annealing) to the problem that D-Wave's computer was specifically designed to solve.[37]
On May 16, 2013 NASA and Google, together with a consortium of universities, announced a partnership with D-Wave to investigate how D-Wave's computers could be used in the creation of artificial intelligence.
Prior to announcing this partnership, NASA, Google, and Universities Space Research Association put a D-Wave computer through a series of benchmark and acceptance tests, which it passed.[14]
Independent researchers found that D-Wave's computers could solve some problems as much as 3,600 times faster than particular software packages running on conventional digital computers.[14]
Other independent researchers found that different software packages running on a single core of a desktop computer can solve those same problems as fast or faster than D-Wave's computers (at least 12,000 times faster for quadratic assignment problems, and between 1 and 50 times faster for quadratic unconstrained binary optimization problems).[64]
In January 2014 researchers at UC Berkeley and IBM published a classical model reproducing the D-Wave machine's observed behavior, suggesting that it may not be a quantum computer.[65]
In March 2014, researchers at University College London and the University of Southern California (USC) published a paper comparing data obtained from a D-Wave Two computer with three possible explanations from classical physics and one quantum model.
They found that their quantum model was a better fit to the experimental data than the Shin–Smith–Smolin–Vazirani classical model, and a much better fit than any of the other classical models.
The authors conclude that "This suggests that an open system quantum dynamical description of the D-Wave device is well-justified even in the presence of relevant thermal excitations and fast single-qubit decoherence." [66]
In May 2014, researchers at D-Wave, Google, USC, Simon Fraser University, and National Research Tomsk Polytechnic University published a paper containing experimental results that demonstrated the presence of entanglement among D-Wave qubits.
Qubit tunneling spectroscopy was used to measure the energy eigenspectrum of two and eight-qubit systems, demonstrating their coherence during a critical portion of the quantum annealing procedure.[67]
A study published in Science in June 2014,[68] described as "likely the most thorough and precise study that has been done on the performance of the D-Wave machine"[69] and "the fairest comparison yet", attempted to define and measure quantum speedup.
Several definitions were put forward as some may be unverifiable by empirical tests, while others, though falsified, would nonetheless allow for the existence of performance advantages.
The study found that the D-Wave chip "produced no quantum speedup" and did not rule out the possibility in future tests.[70]
The researchers, led by Matthias Troyer at the Swiss Federal Institute of Technology in Zurich, found "no quantum speedup" across the entire range of their tests, and only inconclusive results when looking at subsets of the tests. Their work illustrated "the subtle nature of the quantum speedup question."
Further work[71] has advanced understanding of these test metrics and their reliance on equilibrated systems, thereby missing any signatures of advantage due to quantum dynamics.
There are many open questions regarding quantum speedup. The ETH reference in the previous section is just for one class of benchmark problems.
Potentially there may be other classes of problems where quantum speedup might occur. Researchers at Google, LANL, USC, Texas A&M, and D-Wave are working to find such problem classes.[72]
by James Vincent, Sep 28, 2016
Quantum computing firm D-Wave has announced this month its largest ever quantum chip containing 2,000 qubits — double the capacity of its previous biggest system. The chip is scheduled to ship next year, and if it lives up to its promise, it would solidify D-Wave’s position at the forefront of quantum computing, a potentially revolutionary field that would change computing as we know it. But despite D-Wave’s confidence, scientists and academics say the company has never proved its advantages over normal computers. And, more damningly, that using the company’s current methodologies, it never will.
D-Wave’s Colin Williams, the company’s director of business development and a former quantum computing scientist himself, is bullish. “[The new chip] isn’t just bigger,” he told The Verge. “It’s improved in many other ways.”
The Canadian firm’s quantum computing chips are based around a process known as quantum annealing. This renders a set problem (like, for example, trying to find the quickest route home passing through certain points) as a topographical map of peaks and troughs, with the optimum answer to the question defined as the lowest point on that map. While regular computers using static 1s and 0s would have to traverse the entire map to find that point, quantum computers — which use quantum bits, or qubits, that represent 1s, 0s, and both at the same time — can effectively tunnel through the landscape, find the lowest point much faster.
Williams says he’s certain that quantum annealing is the best way to make a quantum computer, and that other approaches are too theoretical. He points out that topological quantum computing (an approach that Microsoft has shown interest in) relies on creating exotic quasiparticles, which are difficult to produce and even trickier to work with. “We’re only at the very very beginning stages of being able to create these particles, let alone perform operations on them,” says Williams. “[Quantum annealing] has tremendous advantages over other schemes.”
But researchers say the benefits of D-Wave’s method have never been proved. A study published in Science in 2014 found that tasks performed on the company’s machines were no faster than conventional computers. The scientists were looking for evidence of “quantum speedup” — the signature advantage of quantum computers which holds that the more calculations you throw at them, the greater a difference in speed they show when compared with classical machines. The paper in Science did not rule out the possibility of D-Wave creating quantum speedup, but certainly found no evidence for it.
“There was only ever a hope that a quantum annealer would be better,” Matthias Troyer, who co-authored the 2014 Science paper, told The Verge. “It turns out that at least for the architecture implemented by D-Wave, [the computation] can be mimicked very efficiently on a classical computer.” Troyer says that simply doubling the number of qubits in its chips will not help D-Wave overcome this problem. “We don’t have any evidence of quantum speedup in this architecture and building a bigger machine will not help that.”
“”Building a bigger machine will not help.””
Other researchers agree with Troyer’s analysis. Scott Aaronson of the University of Texas and Greg Kuperberg of UC Davis tell The Verge that while there was theoretical hope that quantum annealing would produce results, the tests have not borne this theory out. The pair note that papers published by D-Wave and partners supposedly showing its quantum advantage are generally pitting its $15 million chips against the class of processor you’d find in your laptop. What’s more, they say, testers tend to pick computational challenges optimized for D-Wave’s chips, giving the company’s tech a home-field advantage. This, they say, leads to impressive but misleading claims that D-Wave’s technology has been proved to be “100,00,000 times faster” than classical computers.
Kuperberg adds that D-Wave’s qubits are also of low quality compared to those produced by other researchers. “Just because [their chips] are quantum, that doesn’t make them a quantum computer,” says Kuperberg. “That’s like saying that any invention that is influenced by air must be an airplane. Of course, it’s not true; it might instead be bagpipes.”
Jeremy Hilton, D-Wave’s senior vice president of systems, defended the methodologies of these papers. In the case of the Google study claiming a 100 million times quantum speedup, he noted that the decision not to compare D-Wave’s chips to the fastest algorithms available for classical machines was “intentional.” These faster algorithms would not scale to “real-world problem sizes,” says Hilton, and so would not represent the true potential of D-Wave’s chips. “It’s worth noting that one of the inventors of this faster classical algorithm actually works at Google,” said Hilton. “So it is safe to say they have a pretty good idea of how relevant it is for the problems they want to solve.”
“D-Wave says it’s “a decade ahead” of rivals”
Williams noted that while it’s true you can’t measure the quality of a chip in the number of qubits alone, D-Wave’s new software functionalities would also deliver extra power. “We are at least a decade ahead in my opinion and if we can sustain our current pace of innovation we’ll remain a decade ahead, forever,” he said.
Aaronson and Kuperberg would disagree, but say they’re still optimistic about the wider future of quantum computing. Troyer, too, mentions many other promising projects, including those at Microsoft, IBM, and the University of Oxford. Indeed, there have been rumors this year that a team at Google working under one John Martinis (separate to the group testing D-Wave’s chips) are getting near to a breakthrough, with results expected in the coming years.
https://www.theverge.com/2016/9/28/13057414/quantum-computer-d-wave-2000-qubit-chip