Has Google Truly Achieved Quantum Supremacy?

[bhobba]

I was thinking another person might post about this:
https://www.livescience.com/google-hits-quantum-supremacy.html
Is this the breakthrough of the century?

Thanks
Bill

 

[berkeman]

I was thinking another person might post about this:

They have

https://www.physicsforums.com/threads/google-demonstrating-quantum-supremacy.979428/

 

[hilbert2]

Is this the breakthrough of the century?

If it turns out that QC is practical for many purposes and allows the calculation of things that were impossible without it (like a determination of the equilibrium constant for the binding of an inhibitor molecule to an enzyme without doing an actual lab experiment), it may be the breakthrough of the century. However, with the current knowledge it's not even clear whether it's more important than the Higgs boson and gravitational wave findings that have also been done during the first 20 years of this century.

 

[phinds]

I read that IBM seriously disputes their claim that they're quantum computer can do in a couple of minutes something that today's supercomputers would take 10,000 years to do. IBM says it would take about 2 1/2 days. Still impressive, but not what Google's claiming.

 

[DennisN]

Thanks for posting the info and links. I heard about it a couple of days ago, but for some reason I didn't check it out further, I don't know why.

Maybe the achievement is in a superposition of being a small step and a giant leap.

 

[DennisN]

I just saw a video about this which I think was remarkably good for coming from a news agency, so I wanted to share it here. It describes quantum computing from various viewpoints, and also describes the engineering and the qubits in a bit more detail than usual introductions to the subject. Scott Aaronson is also interviewed, and there are many nice shots of the hardware involved.

The Hype Over Quantum Computers, Explained (CNBC Jan 10, 2020)

 

[A. Neumaier]

I was thinking another person might post about this:
https://www.livescience.com/google-hits-quantum-supremacy.html
Is this the breakthrough of the century?

They have

https://www.physicsforums.com/threads/google-demonstrating-quantum-supremacy.979428/

Not yet! See

• IBM and Google disagree on quantum computing achievement

where one can read:

“We are only one creative algorithm away from valuable near-term applications,” the researchers wrote in the Nature paper.

The same can be said about any not yet achieved breakthrough!

 

[A. Neumaier]

See also

 

[OCR]

See also

Ahh, yes. . . !

.

 

[nsaspook]

https://www.science.org/content/art...-can-beat-google-s-quantum-computer-after-all

Ordinary computers can beat Google’s quantum computer after all
Superfast algorithm put crimp in 2019 claim that Google’s machine had achieved “quantum supremacy”

The researchers calculated the output pattern for 1 million of the 9 quadrillion possible number strings, relying on an innovation of their own to obtain a truly random, representative set. The computation took 15 hours on 512 GPUs and yielded the telltale spiky output. “It’s fair to say that the Google experiment has been simulated on a conventional computer,” says Dominik Hangleiter, a quantum computer scientist at the University of Maryland, College Park. On a supercomputer, the computation would take a few dozen seconds, Zhang says—10 billion times faster than the Google team estimated.

The advance underscores the pitfalls of racing a quantum computer against a conventional one, researchers say. “There’s an urgent need for better quantum supremacy experiments,” Aaronson says. Zhang suggests a more practical approach: “We should find some real-world applications to demonstrate the quantum advantage.”

It looks like IBM was correct.
https://www.ibm.com/blogs/research/2019/10/on-quantum-supremacy/

Quantum computers are starting to approach the limit of classical simulation and it is important that we continue to benchmark progress and to ask how difficult they are to simulate. This is a fascinating scientific question.

Recent advances in quantum computing have resulted in two 53-qubit processors: one from our group in IBM and a device described by Google in a paper published in the journal Nature. In the paper, it is argued that their device reached “quantum supremacy” and that “a state-of-the-art supercomputer would require approximately 10,000 years to perform the equivalent task.” 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.

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.

This particular notion of “quantum supremacy” is based on executing a random quantum circuit of a size infeasible for simulation with any available classical computer. Specifically, the paper shows a computational experiment over a 53-qubit quantum processor that implements an impressively large two-qubit gate quantum circuit of depth 20, with 430 two-qubit and 1,113 single-qubit gates, and with predicted total fidelity of 0.2%. Their classical simulation estimate of 10,000 years is based on the observation that the RAM memory requirement to store the full state vector in a Schrödinger-type simulation would be prohibitive, and thus one needs to resort to a Schrödinger-Feynman simulation that trades off space for time.