# Quantum Bayesian Networks

## 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.

## 1 Comment »

1. Concerning scale, it might not be the only factor. Here’s a nice guy wondering if nature is a conspiracy to keep computer scientists busy!

http://blog.sigfpe.com/2013/10/distributed-computing-with-alien.html

Comment by Elagnel Exterminador — December 28, 2013 @ 11:14 am

Create a free website or blog at WordPress.com.