Jan 24, 2018

An excursion around the internet

Here's an interesting post: "Data Science of the Facebook World" by Steven Wolfram of Mathematica fame. I read it this morning as I ambled around the internet. In the post, Wolfram collects a bunch of data from Facebook's Graph API (since changed) and analyzes it.

The journey starts with this Shtetl Optimized post. Shtetl-Optimized is the blog of quantum computing maven Scott Aaronson. It's a "classified post" based on an idea he credits to Scott Alexander's blog, Slate Star Codex--to let the follower community post links to interesting things.

The first, proposed by Scott Aaronson was a link to a site called Quantum Game which teaches some of the fundamentals of quantum mechanics by setting up problems involving lasers, beam-splitters, mirrors, polarizers and other optically active devices. My friend Mark introduced the idea of "lonely photons" and we've been riffing on the subject, mixing metaphor and science. But the science has been about the relativistic behavior of photons: nothing about their quantum-mechanical behavior. This opens new avenues (or landscapes) for exploring photon loneliness.

The Quantum Game site leads to the site of its author,  Piotr Migdal, a young, Polish PhD. H site has links to some interesting posts: Dating for Nerds 1 and Dating for Nerds 2. Both well written, full of tips that would have been very interesting to my 20-year old self.

One of the Dating for Nerds posts leads to the Wolfram post. So there you are.

The image below shows the Quantum Game. I'm using a lab mode, accessed by clicking the infinity sign on the left, and carrying out a series of experiments to help me understand the behavior of photons better so that I can solve the puzzles with less trial-and-error and more understanding.

In the upper right is a palette of experimental equipment. In the center is my lab. Leftmost in the lab is a laser that will fire a photon into a beam splitter. On each beam path, I've put two glass slabs, each of which changes the phase by half a wavelength, and a sugar solution, which changes polarization. I've put a photon detector on each path. If I click on the run button (triangle in lower right) the laser fires a single photon. It will be detected by one or the other of the detectors. The game will show whch one, and what percentage of the time each detector would see a photon.

To the far right, I've dragged a light-sensitive bomb from the palette. Right now it's not on a path that a photon could reach, but if it was in a path, and a photon hit it, then it would explode. The bomb used in an apparatus called an Elitzur-Vaidman bomb detector.

In another experiment, I remove one of the detectors and place the other one on the other side of the second beam splitter. Then I can remove glass slabs and polarizing sugar solutions and see in which cases the photons from the two paths cohere and which way they combine at the second splitter.

I guess I love the Internet