In theory, it cannot be ruled out that the algorithms might run for longer than the age of the universe. But in practice, many algorithms seem to work just fine. Almost always.

If you rotate an image of a molecular structure, a human can tell the rotated image is still the same molecule, but a machine ...

As Preskill puts it, “We have to find those problems that are classically hard, but then we have to that the quantum methods will really be efficient.” A few times, researchers thought they’d done it, ...

Nature talked to one of the people behind these algorithm improvements, who was optimistic that they could eventually replicate all of D-Wave's results using non-quantum algorithms.