Indeed, in a demonstration of just how hazy the quantum future is, and how hotly contested is its ownership, a quartet of scientists from IBM, led by data scientist Edwin Pednault, on Monday challenged Google’s claim that the calculation would take 10,000 years on a regular computer. In a paper published on the physics website arXiv, and in a blog entry posted to IBM’s research website, they estimated that the task could be accomplished in just two and a half days.
“Because the original meaning of the term ‘quantum supremacy,’ as proposed by John Preskill in 2012, was to describe the point where quantum computers can do things that classical computers can’t, this threshold has not been met,” they wrote in the blog post.
They went on to invite aspiring young scientists who wanted to do quantum computing to log on to one of IBM’s machines: “Go ahead and run your first program on a real quantum computer today.”
Google did not respond to a request for comment.
In conversation, Dr. Gil maintained that the term “quantum supremacy” was misleading and rhetorical overkill: “The reality is, the future of computing will be a hybrid between classical computer of bits, A.I. systems and quantum computing coming together.”
He and his colleagues would rather that we not judge quantum computers by qubits at all. They prefer a new metric, “quantum volume,” which takes into account both the numbers of qubits and the amount of error correction.
Quantum volume is doubling every year, according to IBM, but nobody can say how far this doubling must go before things get interesting.
The ultimate goal of quantum supremacy would be to use qubits to crack encryption codes. But that will take a while. Google’s Sycamore computer has all of 53 qubits to its name, as does a new IBM computer, installed online at the company’s Quantum Computation Center in Poughkeepsie, N.Y. System One, IBM’s black cube from tomorrow, only has 20 qubits.