In the race to achieve the coveted “advantage” of a quantum computer, those developing quantum algorithms are pitted against each other and against those working on classical algorithms. With each potential claim of such an advantage — the successful calculation on a quantum computer of something that is infeasible on a classical one — scientists have designed more efficient classical algorithms against which the quantum algorithms must then be compared.
Now, by exactly that route, researchers at the University of Bristol and Imperial College London have knocked down a peg a recent claim of quantum advantage using a method called Gaussian boson sampling. The team behind that advantage claim had asserted that a classical computation of Gaussian boson sampling would take 600 million years on the world’s fastest supercomputer. But they showed that their classical algorithm can do it in just 73 days. This result, along with other recent improvements to classical algorithms, helps build the case that the quantum-advantage race is far from over.