Quantum Bayesian Networks

March 1, 2015

Spock programming a Quantum Computer

Filed under: Uncategorized — rrtucci @ 4:54 am

To boldly go where no man has gone before.
Space, the final frontier.
Live long and prosper, Leonard Nimoy.

The TV series Star Trek inspired many baby boomers to dream about space travel, and, sometimes, to pursue careers in science and engineering. By far, one of the main attractions of the series was Dr. Spock or Mr. Spock, chief science officer of the starship Enterprise (played by Leonard Nimoy, who passed away a few days ago. RIP). Dr. Spock epitomizes the voice of pure, flawless logic inside everyone of us. Dr. Spock has achieved the rare distinction of becoming a universally known fictional character, an archetype, and a scientist too. I dare say 99% of the population of the world is familiar with Dr. Spock’s looks and quirky personality. This has been true since the first Star Trek episode aired in 1966, and continues to be true today.

"Fascinating code" (Picture of Dr. Spock programming a quantum computer in PyQMeld)

“Fascinating code”

(Picture of Dr. Spock programming a quantum computer in PyQMeld)

PyQMeld is a programming language made in the year 2050 by small-dragonfly. It combines Python, Vulcan mind meld, and quantum Bayesian networks.

P.S. I am currently writing a paper applying Group Theory to quantum computing. The paper is going very well, but it’s still very far from completion. It’s going to be a long one.

February 26, 2015

What does a quantum computer look like?

Filed under: Uncategorized — rrtucci @ 6:35 pm

Since time immemorial, scientists have been grappling with the thorny, open, research-question of what does a quantum computer look like (or rather, will look like). Here is my artist’s rendition. I’m sure better scientists than I can come up with more elevating and edifying portrayals, but this is my own, dammit. (This picture was inspired by my previous blog post. It is based on this image. I also used pictures of Atlas, a robot made by the Boston Dynamics company, which is now owned by Google. I hope my Greek friend Angelo aka ElAngelExterminador approves of my allusion to sublime Greek culture).

February 25, 2015

Maybe You Should Believe Sean Carroll

Filed under: Uncategorized — rrtucci @ 5:35 am

3corcovado-sean-carrollPhysicist (cosmologist) Sean Carroll, a darling of the popular-science press, is a vocal atheist. Although he does not believe in the existence of God, because it’s an untestable theory, he does believe in the Many Wor(l)ds Interpretation of quantum mechanics (MWI), another untestable theory. In a recent blog post, Sean pities those who do not believe in the true interpretation, for they shall not see the glory of heaven. According to Sean, MWI is easily derivable, using only pure logic, from a few, very simple, widely accepted axioms. Sean has devoted considerable time and effort to proving the existence of many worlds and disproving the existence of God.

I’m afraid I’m one of those nonbelievers that Sean pities so much. See my opinion of MWI here.

Although I don’t believe in MWI, I do have a scientific religion, quantum computation. There is a big difference between QC and MWI, though. Quantum computation is a testable theory. Even better, its ultimate goal is to construct a tangible, physical machine. That machine is a God to me, a Deus ex Machina. I believe that this God/machine will descend from heaven (thanks to a handy crane) at the end of the play, and save the day, just in the nick of time, when the situation seemed all but hopeless.

February 3, 2015

Scott Aaronson Bites Seth Lloyd’s Ear

Filed under: Uncategorized — rrtucci @ 4:04 pm

Yesterday was an eventful Groundhog Day.

Check out

Jimmy the Groundhog turns on the mayor
(Feb 2, 2015, Chicago Tribune)


SUN PRAIRIE, Wis. — A mayor in Wisconsin has learned a valuable lesson about his city’s weather-predicting critter: Don’t get too close.

Jimmy, the official groundhog in Sun Prairie, bit the mayor’s ear during a Groundhog Day celebration Monday. The groundhog’s handler was holding the animal next to Mayor Jonathan Freund’s face when it promptly bit down on his ear. Freund flinched but went on with his declaration that Jimmy had predicted an early spring.

Will the groundhog see its shadow? It’s a question asked of the country’s most famous critter, Punxsutawney Phil, every Feb. 2 in front of anxious crowds desperate to know whether spring is around the corner or if six more weeks of winter must be endured.

The Groundhog Day celebration became even more precarious when Jimmy’s handlers, Jerry and Maria Hahn, said the mayor had gotten it wrong and that there would be six more weeks of winter. Then the city later issued a statement saying only the mayor can translate Jimmy’s prediction.

Next, check out Scott Aaronson’s newest essay, which occurred on the same day, but 1000 miles away, in Boston, MA:

Quantum Machine Learning Algorithms: Read the Fine Print, by Scott Aaronson

Do read the fine print—he really means it: the whole paper is written in 9 point font.

Is Scott burying Lloyd or praising him? His essay does both.

This is Scott’s argument, his impeccable logic, in my own words: Seth Lloyd and his minions have proposed an algorithm for doing AI with a quantum computer. Their dodo bird algorithm could, under certain totally impractical circumstances, fly. To put it differently, their dodo bird is a very promising “template” for the evolution of flying birds, a veritable “mini-revolution” in aviation history. In fact, their dodo bird flies almost as well as … a chicken.

In this video, Matthias Troyer also points out that the AI algorithm proposed by Lloyd et al is virtually useless in its present form.

Scott doesn’t deign to mention the existence of other algorithms for doing AI with a quantum computer. For example, the annealer algorithms used by D-Wave/Google/NASA, or gate model algorithms (such as one proposed by Microsoft people and one proposed by me) based on Grover’s algorithm.

Related blog posts:

(click icons to enlarge them)

January 28, 2015

25th birthday of Ergo (Bayesian Network Software)

Filed under: Uncategorized — rrtucci @ 7:37 am

“Ergo” of course is Latin for “therefore”. The philosopher René Descartes famously said “Cogito ergo sum”, which means “I think therefore I am” .

For a long time, I’ve been advising people who are learning classical Bayesian networks (CB nets) for the first time to try a CB net computer program. Such programs are really captivating, at least to me, and they are very helpful for learning about CB nets. Nowadays, there are many CB net computer programs available. For many years, Kevin Murphy, a Prof. at the Uni. of BC, Canada, has kept a list of them here.

One of the first, if not the first, CB net computer program with a GUI was written circa 1990, 25 years ago, by “Noetic Systems Inc.”. It was called Ergo. Recently, the authors of Ergo posted on arXiv one of the original white papers describing their software: http://arxiv.org/abs/1304.1095

If you are going to try your first CB net computer program, I think Ergo is a great place to start. Ergo was the first CB net program I ever tried, and it was love at first sight for me. The nice thing about Ergo vis-à-vis other, more recent CB net computer programs is that it’s much simpler. The latest CB net programs have a gazillion more features so it’s easy to get lost in their complexity. That’s why I advise you to start off with Ergo, and then, once you develop an appetite for more features, you can try the newer programs.

It’s amazing and a good testament to the very far backward compatibility of MS Windows software, that Ergo still works 25 years later on Windows XP and later versions of Windows too(?)

The trial version of Ergo for Windows (It’s a crippled version that doesn’t allow you to save files) was available on the internet until maybe 5(?) years ago, but I can no longer find a link to it. In tribute to CB net history, I am making it available here at my website. I’m doing this without the permission of the Ergo authors. If they come forward and ask me to remove it, I will immediately comply with their request.

January 19, 2015

Matthias Troyer Makes a Compelling Case For Using QCs to do Quantum Chemistry

Filed under: Uncategorized — rrtucci @ 3:10 pm

Check out this great video.

I think Matthias gives great talks, full of useful information. Note that this talk occurred on Google territory on Dec 2, 2014. It was posted on YouTube on Jan 13, 2015.

January 14, 2015

QIP 2015 at Sidney Another Resounding (ZZZ…) Succezzz

Filed under: Uncategorized — rrtucci @ 6:52 pm

Photo showing lively audience participation while Academic Clone 313 presents his paper ZZZ at QIP 2015 conference. (QIP=Quantum Information Parody). Paper ZZZ has been in arXiv for months. Anyone interested in ZZZ could have downloaded it as a pdf from arXiv months ago. Anyone with any serious questions about ZZZ could have addressed them to Academic Clone 313 via internet months ago. If paper ZZZ were that important, Academic Clone 313 could have used video-chat (such as Google Hangouts) or video-sharing (such as youTube) or a blog post or a webpage to speak about ZZZ months ago, instead of flying half way around the world to Australia to deliver his message only once, to only a few somnolent people.

December 29, 2014

if (software unavailable) then (computer worthless)

Filed under: Uncategorized — rrtucci @ 4:18 pm

As every science geek knows, on Jan 1975 (40th anniversary), the Altair 8800, a personal computer only available as a mail order, build-it-yourself kit for hobbyists, was featured on the front cover of Popular Electronics magazine. Bill Gates and Paul Allen immediately wrote a BASIC programming language for the device, the first product of the Microsoft corporation. Without their code, all you could do with this “first PC” was to toggle manually its front panel switches so as to make its lights blink in an interesting way. Similarly, without good software, quantum computers will be a totally useless pile of electronic junk. Is the Microsoft saga about to repeat itself for quantum computers?

Listen to Bill Gates tell the story.

November 18, 2014

Houston, Tranquility Base here, the Dragonfly has landed

Filed under: Uncategorized — rrtucci @ 9:18 pm
Houston, Tranquility Base here, the Dragonfly has landed. (image based on NASA photo from here)

Houston, Tranquility Base here, the Dragonfly has landed.
(image based on NASA photo from here)

Pacific Spiketail Dragonfly (Photo from here

Pacific Spiketail Dragonfly (Photo from here)

The new Artiste logo reminds me of a dragonfly. Like many people, I’ve been fascinated by dragonflies since I was a child. Here are some interesting facts about dragonflies (taken from references at the end of this blog post):

Dragonflies and damselflies are often called the “jewels of the pond”.

Damselflies rest with their wings closed like butterflies. Dragonflies, on the other hand, keep each wing pair at opposite sides of their thorax when at rest.

Dragonflies are among the fastest flying insects. (which, however, is not that fast). In general, large dragonflies like the hawkers have a maximum speed of 10–15 meters/sec (22–34 mph) with average cruising speed of about 4.5 meters/sec (10 mph).

Dragonflies can fly in all 6 directions: front, right, left, up, down and backwards. They can fly upside down, and can change direction quickly. They can hover for as long as a minute.

Each of their 4 wings has a separate muscle and can be maneuvered independently.

They can eat and mate in midair without need to alight.

Food Chain
They have a voracious appetite, especially for mosquitoes. They will use a person or other mammal (e.g., horses or cows) as bait. They will hover right above their bait, and when the bait attracts a mosquito, they will pounce on it.

Besides mosquitoes, they eat other small insects like flies, bees, ants, wasps, and very rarely butterflies.

Though dragonflies are predators, they themselves are subject to being preyed upon by birds, lizards, frogs, spiders, fish, water bugs, and even other large dragonflies.

Life cycle
From egg to underwater gilled larva (called a naiad or nymph) to adult flying stage. Larval stage may last anywhere from 2 months to 5 years depending on species. Adult flying stage can last anywhere from a few weeks to 6 months depending on species.

Adult dragonflies do not normally bite or sting humans. They don’t have a stinger at the end of their tails; they use that to lay eggs. If you trap one in your hands without crushing it, it will try to bite you with its mouth, but it will fail to break your skin. Nymphs, however, are capable of delivering a painful but harmless bite.

Hunting Effectiveness
African lions capture prey about 25% of the time
Sharks about 50% of time
Dragonflies about 95% of time.

A dragonfly comes equipped with very sophisticated target acquisition and Kalman filtering capabilities. It is able to focus on a single target prey amid a cloud of similarly fluttering insects. It is able to make very subtle mid-course corrections to intersect that moving target.

They have a nearly full (4pi) field of vision. Each eye has about 30,000 facets. But they can’t hear at all and they can’t smell very well either.

Their order is Odonata, which means “toothed ones” — because of their noticeably serrated mandibles. Infraorder Anisoptera (from the Greek for “uneven wings”)

They first arose in the Carboniferous period, about 300 E6 years ago. For comparison, the Earth is 4.5 E9 years old, and the six animal classes are this old:

  1. Invertebrates- 600 E6 years
  2. Fishes – 510 E6 years
  3. Amphibians – 370 E6 years
  4. Reptiles – 315 E6 years
  5. Mammals – 200 E6 years but exploded 65 E6 years ago after great extinction
  6. Birds – 150 E6 years

Some dragonfly species migrate long distances each year, a still mysterious phenomenon not unlike the celebrated flight of the monarch butterfly. Recent studies have shown that green darner dragonflies migrate in sizable swarms each fall and spring between the northern United States and southern Mexico, while the globe skimmer dragonfly lives up to its name: it has been tracked crossing between India and Africa, a round trip, multigenerational pilgrimage that may exceed 10,000 miles.


November 9, 2014

Are Feynman Path Integrals Useful In Quantum Computing?

Filed under: Uncategorized — rrtucci @ 5:20 am

Contemporary High Energy physicists seldom formulate their new theories in the Schroedinger picture (or associated operator pictures like the Heisenberg or Interaction pictures). They prefer instead to formulate their theories in terms of Feynman path integrals because such integrals exhibit the symmetries of the theory more explicitly without having to worry about operator ordering. So an important question to ask is, are Feynman path integrals useful in Quantum Computing too? I would say, yes, absolutely. This is how I personally see it:

operator pictures ~ quantum circuits

Feynman path integral picture ~  quantum Bayesian networks

The analogy is not perfect, but it’s very close, in my opinion.

A related post is:
Quantum Circuits in the Dirac, Quayle and Bayes Conventions

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