# Quantum Bayesian Networks

## May 7, 2017

### Enter The Dragon Into The QC Race

Filed under: Uncategorized — rrtucci @ 3:13 pm

Chinese quantum computing has been prominently in the news recently. Two news items about it that have come to my attention are:

(1)
First, an article in the conservative journal National Review
warning about the dangers of America falling behind China in the quantum computing “arms race”. I see America’s race with China to build a QC more as a commercial race to achieve supremacy in a new market than as an arms race. The article doesn’t mention Russia or India, probably because those two players have not invested as much money and seem far less committed than USA and China to this race. The article fails to mention that there are some types of crypto that are unbreakable by a QC, so, as long as the world starts migrating to those types of crypto a few years before QCs are available, the world’s secrets will remain safe. Maybe some old docs, encrypted in the QC vulnerable encryptions, will fall in the wrong hands, but I don’t see that as a very serious problem. Secrets usually have a short expiration date anyway. The National Review article does make a point that I consider very true and important:

“Yet with China graduating 4.7 million of its students per year with STEM degrees while the U.S. graduates a little over half a million, how long can the U.S. maintain its lead?

(2)
Second, a Boson Sampler experiment. Scott Aaronson is one of the fathers of BS, so let me just quote his BS explanation, as posted in his BS blog, Shtetl Optimized:

… a group in Shanghai, led by Chaoyang Lu and Jianwei Pan, has reported in Nature Photonics that they can do BosonSampling with a coincidence rate that’s higher than in previous experiments by a factor of several thousand. This, in particular, lets them do BosonSampling with 5 photons. Now, 5 might not sound like that much, especially since the group in Bristol previously did 6-photon BosonSampling. But to make their experiment work, the Bristol group needed to start its photons in the initial state $|3,3\rangle$ that is, two modes with 3 photons each. This gives rise to matrices with repeated rows, whose permanents are much easier to calculate than the permanents of arbitrary matrices. By contrast, the Shanghai group starts its photons in the “true BosonSampling initial state” $|1,1,1,1,1\rangle$ that is, five modes with 1 photon each. That’s the kind of initial state we ultimately want.

To me, quantum computers are mostly a commercial product, just like PCs, the Cloud and HPC. Most of the best progress in quantum computing in America is being done by commercial companies (IBM, Google, Microsoft, DWave, etc.), not by academia or aerospace. China with its 1.4 billion inhabitants compared to America’s 300 million, is certainly an enticing market to any company.

Our company Artiste-qb.net already has a small toe-hold in China. Our CTO and part owner, Dr. Tao Yin, lives in Shenzhen, China, where he represents us. Our BayesForge.com product is currently only on the Amazon cloud (AWS), but we are currently working to translate it to a Docker image. Once we do so, we may also make it available on the Alibaba Cloud.

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