According to a paper published in Nature Google has developed a quantum computer.
The promise of quantum computers is that certain computational tasks might be executed exponentially faster on a quantum processor than on a classical processor. A fundamental challenge is to build a high-fidelity processor capable of running quantum algorithms in an exponentially large computational space. Here we report the use of a processor with programmable superconducting qubits to create quantum states on 53 qubits, corresponding to a computational state-space of dimension 2^53 (about 10^16).
Measurements from repeated experiments sample the resulting probability distribution, which we verify using classical simulations. Our Sycamore processor takes about 200 seconds to sample one instance of a quantum circuit a million times—our benchmarks currently indicate that the equivalent task for a state-of-the-art classical supercomputer would take approximately 10,000 years. This dramatic increase in speed compared to all known classical algorithms is an experimental realization of quantum supremacy for this specific computational task, heralding a much-anticipated computing paradigm.
On a cautionary note, Google's central claim, that they have performed in 200 seconds computation that would take current state-of-the-art supercomputers 10,000 years is disputed by IBM in a blog post which claims that:
We argue that an ideal simulation of the same task can be performed on a classical system in 2.5 days and with far greater fidelity. This is in fact a conservative, worst-case estimate, and we expect that with additional refinements the classical cost of the simulation can be further reduced.
3 minutes 20 seconds to perform what would take 2.5 days is still pretty impressive and presumably up-scaling would produce (exponentially) better results.
Note that quantum computing is not so well suited to linear processing, such as would typically be used to generate tablebases, but is ideally suited to highly parallel processes like those used in AlphaZero.
Does this advance mean we can look forward to a vastly improved AlphaZero?