# Quantum Bayesian Networks

## December 28, 2013

### Gay Bayesian

Filed under: Uncategorized — rrtucci @ 11:09 am

Alan Turing used Bayesian techniques to break the German Uboat codes, thus contributing significantly to bringing WW2 to an end.

## December 26, 2013

### Have a Merry Nano (Little) Christmas

Filed under: Uncategorized — rrtucci @ 10:52 pm

My Christmas feel good message. If Queen Elizabeth and Edward Snowden can have one, so can I.

Methanol

The molecule for methanol. It resembles a Christmas bird with a long neck, like a white stork or a Japanese crane. The OH radical is the long neck, and the 3 hydrogens are the two wings and the tail. By the way, here’s how to make an origami crane, a nice decoration for a Christmas tree.

Ethanol

The molecule for ethanol. It resembles Rudolph the Red Nosed Reindeer. The OH radical is the neck and the 5 hydrogens are the 4 legs and the tail. One more CH_2 than methanol makes it non-poisonous but it still has a kick to it. Ethanol is the alcohol in distilled spirits that we drink at Christmas time.

Chemical bond lengths are typically 200 picometers = 0.2 nanometers. Quantum Computers don’t necessarily have to be of molecular sizes. For example, those based on SQUIDs like the ones made by D-Wave or Martinis aren’t. D-Wave chips have “0.5-micron junctions and 0.25-micron lines and spaces“. Recall 1 micron = 1,000 nanometers. vacuum wavelengths:
Radio Waves: 100km to 1mm=10^6nm (microwaves: 0.3m to 3mm)
IR: 1mm=10^6nm to 750nm(red)
Optical: 750nm to 400nm,
UV: 400nm to 1nm,
X Rays: 1nm to .001nm.
Since $\lambda = v/f$ and light travels slower than c in solids, the wavelengths are smaller in a solid than in the vacuum for the same frequencies.

A funny coincidence is that semiconductor chips with 14nm nodes are scheduled to arrive next year, 2014. If the trend continues, 5nm nodes will be available by 2019.

Nanotechnology is usually defined as the manipulation of matter with at least one dimension sized from 1 to 100 nanometers. This is a very broad definition that includes all of chemistry. Quantum mechanical effects are rampant at those scales.

Even though the first QC’s may be too big to qualify as nanotech, it’s very likely that QC’s will progress towards those smaller sizes, because it’s easier to preserve quantum coherence for smaller systems than for larger ones.

Since quantum computers and nanotech are so intimately related, perhaps it’s not too surprising that Richard Feynman (and others) invented both of these technologies. Feynman “invented” nanotechnology in his famous 1959 talk “There is plenty of Room at the Bottom”, and he “invented” quantum computers in his 1982 talk “Simulating Physics with Computers”.

Quantum mechanics is now almost 100 years old. It has been tested to a precision of 10^-10 or better (check out The Most Precisely Tested Theory in the History of Science, by Chad Orzel)

I hear Santa is working on a quantum computer for next year. Santa does not live in Waterloo, Canada. He doesn’t even like the place.

## December 19, 2013

### Where the Wild Bayesian Network Things Are

Filed under: Uncategorized — rrtucci @ 5:41 am

In a recent blog post, Judea Pearl tries to answer a question that skeptics of Bayesian Networks often ask: “But where does the graph come from?”. His answer is for adults. In the future, I promise to give an adult sounding answer too. But for now, let me give an answer for ages 3 to 6.

I think the graphs come from an island about a year away by boat. The island isn’t easy to find, but if you look hard enough, with enough imagination, with a subversive spirit, you will certainly find it, and have a wild rumpus with its inhabitants, but only for a while.

For me, the human brain is the mother of all Bayesian Networks, each person is a unique wild Bayesian Network thing. So for me, ultimately, the graphs come from…everywhere, they are all around us, Bayesian Network graphs is people!

Text of Where the Wild Bayesian Network Things Are
by Maurice Sendak

The night Max Judea wore his wolf suit and made mischief of one kind

and another

his mother called him “wild Bayesian Network THING!”
and Max Judea said “I’LL EAT YOU UP!”
so he was sent to bed without eating anything.

That very night in Max’s Judea’s room a forest grew

and grew –

and grew until his ceiling hung with vines
and the walls became the world around

and an ocean tumbled by with a private boat for Max Judea
and he sailed off through night and day

and in and out of weeks
and almost over a year
to where the wild Bayesian Network things are.

And when he came to the place where the wild Bayesian Network things are
they roared their terrible roars and gnashed their terrible teeth

and rolled their terrible eyes vertices and showed their terrible claws edges

till Max Judea said “BE STILL!”
and tamed them with the magic trick

of staring into all their yellow eyes vertices without blinking once
and they were frightened and called him the most wild Bayesian Network thing of all

and made him king of all the wild Bayesian Network things.

“And now,” cried Max Judea, “let the wild Bayesian Network rumpus start!”

“Now stop!” Max Judea said and sent the wild Bayesian Network things off to bed
without their supper. And Max Judea the king of all the wild Bayesian Network things was lonely
and wanted to be where someone loved him best of all.

Then all around from far away across the world
he smelled good things to eat
so he gave up being king of where the wild Bayesian Network things are.

But the wild Bayesian Network things cried, “Oh please don’t go—
we’ll eat you up – we love you so!”
And Max Judea said, “No!”

The wild Bayesian Network things roared their terrible roars and gnashed their terrible teeth
and rolled their terrible eyes vertices and showed their terrible claws edges
but Max Judea stepped into his private boat and waved good-bye

and sailed back over a year
and in and out of weeks
and through a day

and into the night of his very own room
where he found his supper waiting for him

and it was still hot.

## December 18, 2013

### In Love With Inkscape

Filed under: Uncategorized — rrtucci @ 8:10 pm

From time to time, I write posts rhapsodizing software programs that might be of interest to the budding quantum computer researcher. Recently, I’ve fallen in love with Inkscape, a software program for drawing high quality vector graphics figures. Inkscape is exquisitely designed and very powerful, a true labor of love. And it’s free, very stable and multi-platform!

For LaTex users, Inkscape is a godsend because it ALLOWS YOU TO USE LATEX INSIDE A FIGURE, and then it allows you to save the figure as an .eps (encapsulated postscript) file, which is a vector graphics format that LaTex likes. Unless you ask Inkscape to save in another format like .eps, it saves files as .svg (scalable vector graphics), another vector graphics format.

If you use pdfLatex instead of the original LaTex, you can display figures that are .jpg or .png, but those are raster graphics instead of vector graphics. (pdfLatex also accepts figures in .pdf, which can be vector graphics if they are generated and saved by software like Inkscape). Raster graphics is good for photos with lots of colors and color gradients, but not so good for figures composed mainly of simple line segments and just a few colors, as are most of the figures found in physics and mathematics papers. Not so good because raster graphics files (1) don’t scale well, becoming blurry upon zooming in, (2) are too big in file size compared to vector graphics files when dealing with simple line drawings.

Another big bonus of Inkscape is that it works hand in glove with plots generated by Octave. (Octave, another wonderful and free software program, is a partial clone of MatLab). For example, here is an Octave .m file that draws a simple 2D plot on the screen, and also saves the plot as an .svg file. This is the .svg file that the .m file generates. (Web browsers can open .svg files, just like they can open many other types of graphic formats). You can open this .svg file with Inkscape, touch up the figure (for instance, add to it some LaTex insets), and then ask Inkscape to save it as an .eps file. Everything a LaTex user burning to show some plots in his LaTex paper could wish for.

(Octave gives you the option of plotting with either the OpenGL or GnuPlot plotting engines. Both engines allow you to save your graph in .svg or .eps formats, and many other graphics formats too).

(When confronted with plottable data, my first impulse is always to download it to a spreadsheet like Excel or Calc, the OpenOffice equivalent of Excel, and then to plot things there. This is a very good first step, but unfortunately, the plots generated by Excel cannot be saved in a vector graphics format, at least not in the old version of Excel that I have. So after using Excel to decide exactly what are the best things to plot, I re-plot with Octave and touch up with Inkscape as described above).

## December 11, 2013

### qJennings thinks qWatson is a moron

Filed under: Uncategorized — rrtucci @ 4:04 am

As I’ve mentioned in earlier posts, I’m currently working on Operation Lisbeth (the goldfish with the dragon tattoo), a top secret project here at my mega corporation Artiste. Operation Lisbeth is a DISRUPTIVE TECHNOLOGY 🙂 that combines quantum computing and AI. I’m almost finished writing a Java applet that generates a quantum circuit of my algorithm if the user enters certain input parameters. The quantum circuit is outputted in super advanced ASCII graphics.

Maybe tomorrow I’ll wake up and realize that there is a fatal flaw in my algorithms, but for today at least, I’m feeling quite satisfied with myself because I think I really nailed the name of my Java application. I named it qJennings. Someday IBM will produce a quantum computer application called qWatson that will try to match its wits against qJennings and fail. My Oh my Mr. qJennings, we are feeling smug today.

qJennings logo, qJennings Strikes Back, The Return of the Jedi qJennings

## December 1, 2013

### The Popeye Comic Book of Quantum Valley Investments

Filed under: Uncategorized — rrtucci @ 9:32 am

Wimpy: What will you have, Sir?
I recommend the specialty of the house,
NMR quantum computer hamburg
with a side dish of quantum crypto hamburg.
Popeye: What, no spinach?

Quantum Valley Investments, Waterloo, Canada. Everything except quantum computers.

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