An Introduction to Quantum Computing, Without the Physics

Very visual example of how Shor's algorithm works to solve factoring. Nothing more than basic arithmetic required.

The big takeaway for me was, it's not just "try every combination at once" as per pop lit on the subject. QC doesn't really do that. To get QC to work any better that traditional for any task, you need to get lucky and stumble across an algorithm that QC can excel at for that task. Just from reading Scott Aaronson's article, it seems likely that most tasks simply don't have a QC optimization, so perhaps QC won't change much at all. (Well, except cryptography, which may change everything...)

1. https://www.research.ibm.com/ibm-q/

This is IBM Quantum experience. Click on "experiment" to start. It has a nice tutorial.

2. http://algassert.com/quirk

I like this one much better, because you can see the internal state of the machine at any moment. And it has much more options and is much faster.

The only thing that caught my eye as off was totally minor. They say the many-controlled-Z gate used by Grover's algorithm can be done in O(n^2) constant-sized gates with an argument-by-reference, but with that type of argument you might as well give the tight bound of Θ(n).

Well, is there much "physics" in (theoretical) quantum physics anyway? It's pretty much all math - just like in this paper!