Quantum computing: hype vs reality - by Dan Elton
Notice this was not just from Google Quantum, it was from Google Quantum AI. Google was not satisfied with limiting themselves to just one buzzword.
This was a marketing coup. The Google team announced that their chip, named Willow, solved a problem in just five minutes that would take a supercomputer 10,000,000,000,000,000,000,000,000 years. This accomplishment made headlines around the world:
But what was this problem that they solved? It’s a problem that Google invented several years ago called “quantum circuit sampling.” This is not the first time they’ve used this problem to compare their quantum machines to classical computers. Here’s how quantum physicist John Preskill describes it:
“The problem their machine solved with astounding speed was carefully chosen just for the purpose of demonstrating the quantum computer’s superiority. It is not otherwise a problem of much practical interest."
Quantum circuit sampling involves creating a random quantum circuit and then sampling from the output. This is very difficult for classical computers to do, because the number of possible states you have to keep track of to simulate the evolution of a quantum circuit grows exponentially with the number of qubits. It is a problem with zero practical utility. Google’s Willow chip has 105 qubits, which is far beyond what classical computers can simulate. So this accomplishment is not surprising and is not a sign of any major progress.
