Quantum computers has been on news a lot lately. Scientists claim to have achieved “quantum supremacy”, a breakthrough that could change computing history. But has that breakthrough really happened or not?

# Google Confirms Achieving Quantum Supremacy

https://gizmodo.com/google-confirms-achieving-quantum-supremacy-1839288099

Google scientists confirmed in a blog post that their quantum computer had needed just 200 seconds to solve a problem that they claim would take the world’s fastest supercomputer 10,000 years to complete.

The team first ran the algorithm last spring using a 54-qubit processor called “Sycamore.”

While the achievement is called quantum supremacy, it doesn’t mean that quantum computers are suddenly more capable than classical computers in more than just a few special applications.

# IBM: No, Google Didn’t Achieve Quantum Supremacy

https://www.tomshardware.com/news/ibm-disputes-google-quantum-supremacy-supercomputers

In a research paper shared Monday, IBM contesting the a leaked Google paper pointing to a Google quantum computer having better performance than a classical supercomputer.

# IBM casts doubt on Google’s claims of quantum supremacy

https://www.sciencemag.org/news/2019/10/ibm-casts-doubt-googles-claims-quantum-supremacy

“It’s a great scientific achievement,” says physicist Chad Rigetti, founder and CEO of Rigetti Computing in Berkeley and Fremont, California, which is developing its own quantum computers. “Google called their shot,”

For certain computational problems, all potential solutions can be thought of as quantum waves simultaneously sloshing among the qubits.

# Quantum supremacy using a programmable superconducting processor

https://www.nature.com/articles/s41586-019-1666-5

To achieve quantum supremacy, we made a number of technical advances which also pave the way towards error correction. Researchers developed fast, high-fidelity gates that can be executed simultaneously across a two-dimensional qubit array. They also calibrated and benchmarked the processor using cross-entropy benchmarking.

## 17 Comments

## Tomi Engdahl says:

https://scitechdaily.com/quantum-supremacy-achieved-by-nasa-and-google/

## Tomi Engdahl says:

https://www.technologyreview.com/s/612596/the-man-turning-china-into-a-quantum-superpower/

## Tomi Engdahl says:

Quantum supremacy from Google? Not so fast, says IBM.

The rival maker of quantum computers is disputing the much-vaunted claim that Google has hit a new milestone.

https://www.technologyreview.com/s/614604/quantum-supremacy-from-google-not-so-fast-says-ibm/

## Tomi Engdahl says:

Google Claims a Quantum Breakthrough That Could Change Computing

https://www.nytimes.com/2019/10/23/technology/quantum-computing-google.html

## Tomi Engdahl says:

On “Quantum Supremacy”

https://www.ibm.com/blogs/research/2019/10/on-quantum-supremacy/

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.

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%.

## Tomi Engdahl says:

https://www.uusiteknologia.fi/2019/10/24/googlen-kvanttikoneen-ydin-esille-katso-videolta/

## Tomi Engdahl says:

IBM: Google’s ‘Quantum Supremacy’ Is 150 Million Percent Wrong (Seriously)

https://www.forbes.com/sites/johnkoetsier/2019/10/23/ibm-googles-quantum-supremacy-is-150-million-percent-wrong/amp/

Google is off by a factor of almost 1.5 million. That’s 150 million percent, and no, it’s not a typo.

That said, quantum computing has so far been largely short on real-world applications, instead relying on claims about speed, cryptography, and virtually limitless potential to keep excitement high.

Google’s current machine used for this test is a 53-qubit quantum computer. That provides 9,007,199,254,740,992 possible states, meaning that this quantum computer can “simultaneously explore a rich space of many possible solutions to a problem,” as Pichai puts it.

As a result, Google says that a calculation that would have taken 10,000 years on even the best state-of-the-art supercomputer took just 200 seconds. And the Google researchers published the result in the scientific journal Nature.

All of which goes to say that if IBM is accurate, Google’s claim for quantum supremacy is seriously in question. While its accomplishment is still impressive, inflating its performance (even accidentally) isn’t a good thing for quantum computing in general.

## Tomi Engdahl says:

https://www.tiede.fi/artikkeli/uutiset/kvanttiherruus-nyt-saavutettu-virallisesti

## Tomi Engdahl says:

https://spectrum.ieee.org/tech-talk/computing/hardware/how-googles-quantum-supremacy-plays-into-quantum-computings-long-game

## Tomi Engdahl says:

Quantum computing’s ‘Hello World’ moment

Certainty principle

https://techcrunch.com/2019/10/26/quantum-computings-hello-world-moment/

quantum computing really exist? It’s fitting that for decades this field has been haunted by the fundamental uncertainty of whether it would, eventually, prove to be a wild goose chase. But Google has collapsed this nagging superposition with research not just demonstrating what’s called “quantum supremacy,” but more importantly showing that this also is only the very beginning of what quantum computers will eventually be capable of.

## Tomi Engdahl says:

Code-breaking quantum computers are closer to reality than anyone suspected.

How a quantum computer could break 2048-bit RSA encryption in 8 hours

https://www.technologyreview.com/s/613596/how-a-quantum-computer-could-break-2048-bit-rsa-encryption-in-8-hours/

A new study shows that quantum technology will catch up with today’s encryption standards much sooner than expected. That should worry anybody who needs to store data securely for 25 years or so.

So computer scientists have attempted to calculate the resources such a quantum computer might need and then work out how long it will be until such a machine can be built. And the answer has always been decades.

Today, that thinking needs to be revised thanks to the work of Craig Gidney at Google in Santa Barbara and Martin Ekerå at the KTH Royal Institute of Technology in Stockholm, Sweden. These guys have found a more efficient way for quantum computers to perform the code-breaking calculations, reducing the resources they require by orders of magnitude.

Consequently, these machines are significantly closer to reality than anyone suspected. The result will make uncomfortable reading for governments, military and security organizations, banks, and anyone else who needs to secure data for 25 years or longer.

practically impossible for a classical computer to factor numbers that are longer than 2048 bits, which is the basis of the most commonly used form of RSA encryption.

Shor showed that a sufficiently powerful quantum computer could do this with ease

noise becomes a significant problem for large quantum computers. And the best way currently to tackle noise is to use error-correcting codes that require significant extra qubits themselves

Now Gidney and Ekerå have shown how a quantum computer could do the calculation with just 20 million qubits. Indeed, they show that such a device would take just eight hours to complete the calculation. “[As a result], the worst case estimate of how many qubits will be needed to factor 2048 bit RSA integers has dropped nearly two orders of magnitude,” they say.

Indeed, security experts have developed post-quantum codes that even a quantum computer will not be able to crack.

For ordinary people, there is little risk. Most people use 2048-bit encryption

https://www.technologyreview.com/s/420287/1978-cryptosystem-resists-quantum-attack/

## Tomi Engdahl says:

https://www.scottaaronson.com/blog/?p=4372

## Tomi Engdahl says:

https://techgrabyte.com/googles-quantum-computer-10k-year-calculation-200-sec/

## Tomi Engdahl says:

Will the quantum economy change your business?

https://techcrunch.com/2019/10/28/will-the-quantum-economy-change-your-business/?tpcc=ECFB2019

Google and NASA have demonstrated that quantum computing isn’t just a fancy trick, but almost certainly something actually useful — and they’re already working on commercial applications. What does that mean for existing startups and businesses? Simply put: nothing. But that doesn’t mean you can ignore it forever.

1. It’ll be a long time before anything really practical comes out of quantum computing.

2. Early applications will be incredibly domain-specific and not generalizable.

## Tomi Engdahl says:

The Race For Quantum Supremacy I VICE on HBO

https://m.youtube.com/watch?v=1lIfbqfoGMo

Computer giants are racing to build the first quantum computer, a device with millions of times more processing strength than all the computers currently on Earth combined.

VICE’s Taylor Wilson meets the scientists at the cutting edge of this new age of computing.

## Tomi Engdahl says:

“Google’s Potential Claim to the Throne of Quantum Supremacy: What does it mean for cybersecurity?”

https://cloudsecurityalliance.org/blog/2019/11/06/google-claim-to-quantum-supremacy-what-does-it-mean-for-cybersecurity/ #quantumcomputing #cryptography #infosec #research #innovation #physics

## Tomi Engdahl says:

https://www.technologyreview.com/s/613596/how-a-quantum-computer-could-break-2048-bit-rsa-encryption-in-8-hours/