Quantum Bayesian Networks

January 16, 2020

So which is better for portfolio optimization, a NISQ Quantum Computer, or Fujitsu’s “quantum inspired digital annealer”?

Filed under: Uncategorized — rrtucci @ 5:21 pm


Quantum computers come in 2 varieties, quantum annealers and quantum gate models. So far, DWave is the only company selling quantum annealers.

A third type of device is now available from Fujitsu. Fujitsu calls its device a “quantum inspired digital annealer”. The Fujitsu device does not have any quantum correlation (quantum entanglement) between separate qubits, so, in that sense, it is not a real qc, and Fujitsu doesn’t claim it is, only that it is “quantum inspired”. DWave, on the other hand, does claim partial quantum entanglement between the separate qubits of its annealer. The Fujitsu device is an optical device which operates at room temperature whereas DWave and most gate model qcs to date operate at milli-kelvin temperatures. Such extremely low tempreatures require expensive refrigeration equipment to maintain.

For the foreseeable future, gate model quantum computing hardware companies that already have devices (IBM, Google, Rigetti, IonQ, Intel, etc.) will only offer what they refer to as NISQ (Noisy Intermediate Scale Quantum) quantum computers. Such computers perform only partial or no error correction on their qubits. qcs are very prone to error. Eventually, in the far future, the aforementioned gate model qc companies hope to develop FTEC (Fault Tolerant Error Corrected) qcs, which are qcs that are fully error corrected. FTEC is an onerous task; so far, the best methods for doing FTEC utilize as many as 1,000 noisy “physical” qubits to produce a single, noise-free, virtual (“logical”) qubit.

There are many companies that do portfolio optimization with classical MCMC (Markov Chain Monte Carlo) ; for example, Quantopian, based here in Boston, where I live.

Portfolio optimization has been proposed by 3 competing factions, 1. DWave, 2. Fujitsu and 3. the NISQ qc hardware companies, as a task that could be performed more economically or faster with their devices than with current classical computers.

Are these 3 competing factions right about beating classical computers, and who of the 3 can do it better?

The purpose of this article is not to answer this question, but rather, just to pose it, and to stress that the FinTech industry is very interested in its answer. The 3 competing factions should be very interested in answering it too, because their profitability in the near term future might depend on its answer. Indeed, if, for example, it turns out that Fujitsu is much better than the other 2 factions, then Fujitsu could end up denying, to the other 2 factions, any significant market share in the affluent and lucrative FinTech industry. Fujitsu might deal a deadly blow to the nascent qc industry, and to the other annealer company, Dwave. Other possible scenarios are that someone shows that classical computers can still beat all 3 factions, or that a new company with a new device, either classical or quantum, joins the fray soon, and proves itself superior to all others.

Of course, if our dreams of building the fabled fully-error-corrected qcs ever come true, then those fabled qcs will be able to perform, according to the scientific theory, much better than the devices of the 3 aforementioned factions. But that is a distant pipe dream for now.

Some references

January 12, 2020

Report reveals that Seth Cesspool Lloyd took $285,000 from Epstein

Filed under: Uncategorized — rrtucci @ 8:36 pm

I’ve written in this blog 2 previous posts (first, second) on the connection between Jeffrey Epstein and quantum computing superstar, Seth Cesspool Lloyd .

Allegedly, Lloyd first met Epstein in 2004 at a John Douchebag Brockman “The Edge” dinner. Today, Lloyd continues his active participation in “The Edge”, an Epstein money laundering operation, while, at the same time, he publicly professes deep, heartfelt remorse for taking money directly from Epstein. A simple ArXiv search reveals that Lloyd acknowledged Epstein in 19 of his ArXiv papers. Also, a picture widely available on the internet shows Lloyd at Epstein’s Lolita island during a scientific gathering there in 2007. Recall that Epstein was convicted in 2008. Lloyd has admitted to visiting Epstein while Epstein was in prison.

A new development in the case is that a report commissioned by MIT and done by an independent law firm, Goodwin Procter LLP, was just released on Jan 10, 2020. As a consequence of that report, Lloyd has been put by MIT on paid administrative leave.

Here is a link to the report and some of its new findings regarding Lloyd.


According to the report,

  • In 2005 or 2006, Lloyd received a gift of $60K from Epstein. He never reported that gift to MIT. The investigators of the report were the first to uncover this gift and reveal it to the public.
  • In 2012, Lloyd received 2 gifts of $50K each. Excerpt from the report:

    the evidence shows that Epstein planned the donations to test whether MIT would accept his money notwithstanding his criminal record. Specifically, Epstein was disappointed that other academic institutions would not accept his money following his 2008 conviction, and, as Epstein put it (using a fishing metaphor) in an email to Professor Lloyd, “im going to give you two 50k tranches to see if the line jingles.”

    This time, instead of reporting that Epstein was the donor, Lloyd reported that someone else, an Epstein assistant, Lesley Groff, was the donor. When MIT phoned Groff about the donation, she revealed that the true donor was Epstein. Nevertheless, the donation was allowed to go through by the MIT officers in charge.

  • In 2017, Lloyd received a gift of $125K from Epstein, which he used to take a sabbatical. This time the donor and donation amount were apparently properly reported to MIT.

The report discusses in detail 9 red-carpet visits of Epstein to the MIT campus.

December 30, 2019

Scott Aaronson excoriates two quantum startups, Xanadu and Zapata

Filed under: Uncategorized — rrtucci @ 3:08 am

Check out the latest blog post by Scott Aaronson in his blog “Shtetl Optimized”

Quantum computing motte-and-baileys

On Dec 2019, a quantum startup called QCWare held a conference called Q2B19, which stands for Quantum to Business 2019. The conference was covered on Twitter under #Q2B19. Price of admission was a paltry 🙂 $1500/person.

Two quantum startups, Xanadu AI and Zapata Computing, unveiled at Q2B19, to much fanfare, new quantum algorithms. In the above blog post, Scott Aaronson argues quite convincingly that the outputs of those quantum algos can be calculated as fast or faster with a classical computer. I see no reason to doubt Scott’s expert analysis of Xanadu’s and Zapata’s quantum algos.

I’ve written previously in this blog several articles denouncing Xanadu as a scam company and a pyramid scheme. I call them a scam because they’ve promised to build a quantum computer based on squeezing, but are advancing at a glacial pace towards that goal. Their main competitor PsiQuantum has 6 times more funding ($230M versus $40M), and a much more promising photonic technology.

Xanadu and Zapata are owned mainly by VCs; each has more than $40M VC funding but no practical products or net profit in sight yet. That is usually a prescription for disaster. VCs are most concerned with making a short term NET profit for their investors. Short term here usually means 3-5 years. I see no way that Xanadu or Zapata are going to achieve a net profit in 3-5 years.

Successful entrepreneurs usually have a profitable product **before** they go to the VCs. They either avoid VC funding altogether, or they use it only as a last resort to scale up the sales of their product. This is all very basic business knowledge. I am a PhD Physicist with very little knowledge about business matters, but even I know this.

December 18, 2019

Baby Yoda drinking the Quantum Kool-Aid

Filed under: Uncategorized — rrtucci @ 8:10 am


December 17, 2019

Sweet Sixteen, 16 Great articles about Bayesian Methods and Networks in classical and quantum physics

Filed under: Uncategorized — rrtucci @ 7:45 pm


I recently came across this wonderful list of classical bayesian network articles

15 Great Articles about Bayesian Methods and Networks, posted by Vincent Granville at DataScienceCentral

To cover the quantum bayesian side of things, here is an article of mine from my blog “Quantum Bayesian Networks”

Google’s TensorNetwork software versus Quantum Bayesian Networks

December 15, 2019

Google’s TensorNetwork software versus Quantum Bayesian Networks

Filed under: Uncategorized — rrtucci @ 9:34 pm


Article Teaser: Tensor networks can be used to denote many physical quantities other than probabilities so they are not tailor made for the job of representing probabilities like Bayesian networks are. Judea Pearl won the Turing prize for his work in Bayesian networks. Hinton, one of the most famous Neural Nets researchers, gives Judea Pearl and his Bayesian networks full credit for motivating the invention of probabilistic AI, which is the natural analogue of quantum AI, except in quantum AI, you replace the probabilities of Probabilistic AI by probability amplitudes. Probabilistic AI software: Probability module of Tensorflow, Pyro extension of Pytorch , PyMC, Stan, Edward, Winbugs, etc., etc. Here is a more in depth comparison between tensor networks and bayesian networks.

Tensor Networks (tnets) have a very long and illustrious history in General Relativity and High Energy Physics: t’Hoof and Veltman used them in Diagrammar to study the renormalization of gauge theories, Penrose applied them to General Relativity, Cvitanovic used them in his “Birdtracks” book to study Group Theory. See this 2009 blog post of mine for some references).

Quantum circuits are clearly a form of tnet. Quantum circuit diagrams were pioneered by Deutsch, who extended the diagrams used by people (e.g., Toffoli and Bennett) working on classical reversible computation by making those diagrams complex valued instead of real valued, and adding single qubit rotations to the CNOTs and doubly controlled NOTS (aka, Toffoli gates) that were already in use in reversible computation.

Guifre Vidal is often credited with being one of the first to use tnets for quantum computing, although he appears to have started using tnets relatively late in their history. This is his first paper in arxiv, dated 2005, where he uses the term “Tensor Network” in the title

Classical simulation of quantum many-body systems with a tree tensor network, by
Yaoyun Shi, Luming Duan, Guifre Vidal, https://arxiv.org/abs/quant-ph/0511070

arxiv search, in chronological order, of all G. Vidal’s papers

The use of tnets in quantum computing software has exploded recently, with the first release on May 2019 by Google of a software library called “TensorNetwork”


A part of tnet history that is never mentioned by the writers and users of Google’s tnet software is its strong connection to a much deeper tool, Quantum Bayesian Networks (qbnets). Just like in General Relativity, where tensor notation can be replaced by the far more geometric language of differential forms, in quantum computing, tensor notation can be replaced by the far deeper language of qbnets. Why deeper? Briefly put, unlike tnets, qbnets are a natural generalization to quantum mechanics of classical bayesian nets. Thus, unlike tnets, qbnets are directly relatable to a rich vein of advances, dating back many decades, by Bayesian network pioneers like Judea Pearl and hierachical model pioneers like Andrew Gelman, and to an equally rich vein of software for Bayesian Networks, hierarchical models, MCMC, etc., such as WinBugs, Stan, Edward, PyMC, Tensorflow’s Probability module, PyTorch’s Pyro extension, etc. I’m afraid that the quantum tnet community is ignoring its precursors and taking credit for inventing the wheel.

In the following 2015 blog post, I explained how tnets and qbnets are related and why qbnets are deeper and more intuitive.

Tensor Networks versus Quantum Bayesian Networks: And the winner is…

I’ve also explained this in the following blog post just 5 months ago

December 11, 2019

Quantum inspired software from Ford and Microsoft

Filed under: Uncategorized — rrtucci @ 9:32 am

Check out

Ford quantum computing experiment cuts traffic, commute times (CNET, Dec 10, 2019)


Quantum computers are highly experimental today, but Ford says it’s got evidence the radical new technology already shows promise for improving transportation. Through a partnership with Microsoft, it used “quantum-inspired” technology — though not an actual quantum computer — to test a traffic-routing algorithm that cut Seattle traffic by 73% and shortened commuting times by 8% in a simulation of 5,000 cars.

“We don’t have to wait until quantum computers are deployed on a wide scale to take advantage of the technology,” said Julie Love, the senior director leading Microsoft’s quantum computing business development. “Using world-class quantum algorithms customized for specific problems, we can bring measurable improvements and drive change that can impact people’s lives.”

So, Ford and Microsoft have cracked the thorny problem of doing quantum computing and achieving a quantum advantage using only a classical computer. And they were able to totally solve the notorious Seattle rush hour traffic problem (population of Seattle and environs is about 3.5 million) using an algorithm that can handle a maximum of 5000 cars out of 1/2 million cars at rush hour, and they achieved an unprecedented, astounding 8% reduction in commute time for 5,000 cars compared to a braindead strategy of no optimizations at all.

Our reporters were able to pierce the veil of corporate secrecy and obtain from a reliable mole within Microsoft, a picture of Microsoft’s quantum inspired quantum computer. Here is a never before released photo of that device. They seem to be imitating DWave’s boxy geometric shape.


December 6, 2019

Is Amazon’s quantum cloud a nothing-burger?

Filed under: Uncategorized — rrtucci @ 7:24 am

4 days ago, I posted this news about the unveiling of Amazon’s quantum cloud “Braket”. Here is some analysis by me of possible future implications of that news.

I think how Amazon Braket ultimately affects qc users and other qc companies will very much depend on who is being affected, and on the quality and properties of the cloud service that Amazon ultimately ends up providing.

For example, if Amazon ends up providing a really good service for doing hybrid quantum-classical AI, there might be little incentive for users to visit the house cloud of companies that specialize in that sort of software like Xanadu or Rahko.

For the companies Rigetti and DWave that already have their own qc hardware and house clouds, I don’t think Amazon Braket will have much of an impact. I doubt it will generate new clients for them. At most, it will cause some of the clients that would have used their hardware anyway to access it in a different way—a less direct way, through an intermediate Amazon server.

Personally, I am ecstatic about the Amazon Braket news, because the Amazon quantum cloud stands a good chance of taking a lot of the clients away from the Microsoft quantum cloud, and I intensely dislike Microsoft, an evil, unethical company. I’m not particularly enamored with Amazon, but I am happy to see those two clobber each other.

I reported about this on Reddit

December 2, 2019

Braket, a new Amazon quantum cloud service, was unveiled today

Filed under: Uncategorized — rrtucci @ 9:08 pm

Check out

Braket, a new Amazon quantum cloud service, was unveiled today. Braket is an AWS image and a jupyter notebook hub, similar to the 3 year old Bayesforge on Amazon, but enhanced so that it provides more direct access to DWave, IonQ and Rigetti qc hardware. I’ve already added Amazon Braket to my ever growing List of Quantum Clouds.

November 23, 2019

List of Quantum Clouds

Filed under: Uncategorized — rrtucci @ 5:41 pm

Clouds for doing quantum computing are becoming increasingly popular. Here is a list with links of those quantum clouds that already exist or are imminent. All are commercial but usually free for small jobs and open to the public. Most use open source qc software but some don’t and have opted to keep their software proprietary. In Alphabetical Order. Thumbs-up emoji indicates working qc hardware. I will update this list as new quantum clouds emerge.

  1. Alibaba-CAS (CAS=Chinese Academy of Sciences) (promised) 👍
  2. Amazon “Braket” 👍
  3. Alpine Quantum Technologies (promised)👍
  4. Bayesforge on Amazon. See also Bayesforge on Tencent
  5. DWave “Leap” (cloud service also via Amazon Braket) 👍
  6. Google (promised. Their quantum cloud will probably be closely linked to Google “Colab”)👍
  7. IBM “Quantum Experience”👍
  8. IonQ (promised, via Microsoft Azure Quantum and Amazon Braket)👍
  9. Microsoft “Azure Quantum” (promised)
  10. PsiQuantum (not yet promised but highly likely due to $230M funding)👍
  11. QCWare “Forge”
  12. QuTech “Quantum Inspire”
  13. Rahko “Hyrax”
  14. Rigetti “QCS”(cloud service also via Amazon Braket) 👍
  15. Strangeworks
  16. Xanadu AI (promised)
  17. Zapata “Orchestra”(promised)

footnote: I have definite opinions about the strengths and weaknesses of each of these quantum clouds which I will gladly share with you, but only by private channels because this topic is very controversial. I’ve worked on quantum computing for almost 2 decades, so my opinions on this subject are very well informed. Full disclosure: I used to work for Artiste-qb.net, the authors of Bayesforge, but I no longer do.

November 19, 2019

The Case Against Seth Lloyd

Filed under: Uncategorized — rrtucci @ 3:55 pm

Veritas Vincit (Truth Prevails)

NBC Television acquires a ‘Quantum Spy’

Filed under: Uncategorized — rrtucci @ 7:50 am

November 18, 2019

Can a quantum computer be used to beat a casino at games of chance?

Filed under: Uncategorized — rrtucci @ 10:28 pm

This question popped into my mind today after seeing an article on games that run on a quantum computer. Currently such games are quite unsophisticated and boring compared with a contemporary video game. But what if the qc is used to play an already existing classical game, akin to how Deep Blue was used to play chess against Garry Kasparov?

Quantum Spies for Hire

Filed under: Uncategorized — rrtucci @ 6:49 pm

Detective spying through newspaper

High paying jobs now open.

We are now hiring industrial spies with expertise in the area of quantum computing. Applicants must have at least a Bachelor’s degree in physics or computer science and be proficient at computer hacking. They must also be willing to relocate to the SF-Bay Area. Alternatively, if the applicant already works for a quantum computing company in the SF-Bay Area, that makes him/her qualified enough to apply for this job.

We have very affluent international clients with interest in acquiring intelligence about the activities, plans, and proprietary technology of certain quantum computing companies. Intelligence acquisition will be in person and via hacking of their intranets. No guns or poisons allowed.

CIA: This post is a joke.

JOB APPLICANT: To contact us, post a for-sale adv in the San Francisco Craig’s list for a Toyota Corolla car of the year 2006. We will reply.

November 17, 2019

PsiQuantum has raised $230 million in funding since it was founded 3 years ago

Filed under: Uncategorized — rrtucci @ 12:57 am

Check out


A secretive US start-up founded ­using technology developed at the University of Bristol has raised $230m (£179m) as it seeks to beat Google and IBM in the race to develop a working quantum computer.

PsiQuantum, founded by former Bristol professor Jeremy O’Brien, has secured the funds from investors ­including a venture capital fund started by former Google executive Andy ­Rubin.

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