In a recent competition, a state-of-the-art quantum computer barely edged out a supercomputer, showing the growing utility of even noisy quantum computers.
[…] a new study shows that, even lacking good error correction, there are ways to mitigate errors that could make quantum computers useful today.
One key to the seeming advantage of IBM’s quantum computer is quantum error mitigation, a novel technique for dealing with the noise that accompanies a quantum computation. Paradoxically, IBM researchers controllably increased the noise in their quantum circuit to get even noisier, less accurate answers and then extrapolated backward to estimate the answer the computer would have gotten if there were no noise. This relies on having a good understanding of the noise that affects quantum circuits and predicting how it affects the output.
Huh, that’s really damn clever.
Just when I think I have a handle on what quantum computing is and start to build a mental model of it, they come up with stuff like this that makes me question myself. I can sort of see how, if the noise had a non-uniform impact on the state of the system how such a thing could be possible. But the fact they actually have managed to do it is amazing to me!