A speed test between quantum and classical computers has ended in a draw. New research suggests the commercial quantum computer sold by Canadian company D-Wave Systems isn’t faster than the PC on your desk.
In theory a quantum computer, which uses the quirks of quantum mechanics to perform calculations, should leave today’s most powerful machines in the algorithmic dust. A classical computer encodes data as familiar zeros and ones, known as bits. A quantum computer, on the other hand, uses subatomic particles known as qubits that can be zero, one, or a simultaneous superposition of the two. This should technically allow a quantum computer to test a huge number of possibilities at the same time. Just how much faster a quantum computer is able to run through a problem than a classical computer is known as “quantum speedup.”
Since 2011, D-Wave has been selling a commercial product that uses a particular architecture known as adiabatic quantum computing to perform calculations. So far, many researchers are skeptical of just how much of an advantage the product gives over other computers. But earlier this year, a team at Google and NASA raced one of D-Wave’s machines against several off-the-shelf algorithms and found that the quantum product was about 35,500 times quicker than the classical solvers.
Not so fast. Google’s test wasn’t exactly a one-to-one comparison because the off-the-shelf products were not optimized to solve these particular problems. Another team has also been testing D-Wave’s machine against regular old computers, running optimization algorithms on both that fairly matched their abilities.
“We found no evidence of quantum speedup,” said physicist Matthias Troyer of the Swiss Federal Institute of Technology in Zurich, Switzerland, co-author of a paper that appeared today in Science. “When we looked at all problems, the machine worked the same as a classical computer.”And the controversycontinues. To read more, click here.