QC Popup Book

Visual Guides to Quantum Computation

An internet pop-up book by Eric Johnston
This is not finished yet, but you're welcome to browse.
©2000-2015 All rights reserved. For more information, please send email to ej@machinelevel.com

Welcome! This pop-up book exists to give software engineers an intuitive understanding of what quantum computers can actually do, and how to use them. My secret evil plan is to kickstart innovation by putting this information into the heads of thousands of clever engineers.

Perpetually Under Construction:
This page is always under construction, always. Currently it contains a bunch of links to whitepapers, and then a complete interactive one-hour lecture on Quantum Teleportation, intended for engineers. The lecture has no text, but I'll be happy to narrate it for you, just ask.

I'd like to extend a special greeting to anyone from Bristol who is exploring this material. I'm a fan of your department's work, and if there's anything you have questions about, please don't hesitate to contact me directly.

Something new to play with:
Click here to play with new features designed to allow photonic hardware implementations of QC programs.

Recently-updated QC whitepapers:
These are written in a casual style, intended to be informal and easy to read. They also contain functional interactive links.

Engineer Q&A
Engineering colleagues send me QC questions, and I try to answer them.
QCEngine Intro for Physicists
Some common QC models, built with QCEngine.
Integration test: lojs
A test of handing QCEngine programs to a quantum linear optics simulator.
GPU version speed testing
The GPU version is back! Several gates still need implementation, but it gives at least a 16x simulation speedup, depending on your GPU.
A Study in Quantum Acceleration of Ray Tracing
A live exploration in building a ray tracing system which benefits from quantum superposition
Mapping to Silicon-based Photonic QC Devices
A live exploration in converting general QC programs to silicon-based etched photonic devices
QQFSM(bf)
A Full-Superposition Quantum Finite State Machine
Circle Paper
A pen-and-paper method for introducing engineers to Quantum Computation

Papers from the past:
These really need to be updated, but they're still fun to read.

An Efficient Framework for Simulation of Quantum Computation
Describes the architecture of this QC simulator.
Machine Level Optimization for Actual and Simulated Quantum Computers
Explores some low-level optimization issues.
AQC Domino
A light-hearted exploration of another style of QC, developed by D-Wave in Vancouver.

Always Live

In each section, you'll find pop-up panels like these:

The pop-up panels are all running active QC simulators, which you're encouraged to play with. The source code to the simulator is all there (and all free). In most browsers, you can just right-click on the page and select view source code.

To the Point

Each section will answer very specific questions about quantum computation, as directly as possible. If the answer is too concise and leaves you wanting more, then I've hit the mark I'm aiming for. Any time I'm tempted to go off on a wordy tangent, I'll insert icons like these: ...which will allow you to go deeper when you want to.

Start Here

I recommend doing these sections in order, but you're welcome to ignore that recommendation and skip straight to teleportation.The earlier sections will still be there when you're ready for them.

Qubits Explained
Entanglement Explained Simply
Quantum Logic
Teleportation Explained Simply
Quantum Encryption
Code Breaking
Quantum Card Tricks
Quantum Database Search

Teleportation Explained Simply

Brown Bag Lunch session by Eric Johnston
April 11, 2012

1. Understand what we're teleporting

2. Look over the steps

3. Learn the operations we need

4. Do it!

5. See a more complex case

Let's do some operations!

	qc.reset(1);
	qc.not();
	qc.hadamard();
	qc.rotate(15);
	qc.phase(15);
	qc.read();
	qc.write(5);
	var valueToWrite = 5; var currentValue = qc.read(); qc.not(currentValue ^ valueToWrite);
	qc.cnot(1, 2);

Alice's prep goes something like this...
	qc.reset(1); qc.write(0);
	qc.rotate(30);

First make an entangled pair...
	qc.reset(3); qint.new(1, 'eB'); qint.new(1, 'eA');
	qint.eA.had();
	qint.eB.cnot(qint.eA);
Let Alice prepare the qubit she wants to send...
	qint.new(1, 'alice'); qint.alice.rotate(30);
Mix it with the entangled pair...
	qint.eA.cnot(qint.alice);
	qint.alice.had();
Read and destroy both of Alice's qubits...
	qc.measure1 = qint.alice.read(); qc.print("m1 = " + qc.measure1 + "\n");
	qc.measure2 = qint.eA.read(); qc.print("m2 = " + qc.measure2 + "\n");
Finally, let Bob use Alice's random data to construct the teleported copy...
	if (qc.measure2) qint.eB.not();
	qint.eB.hadamard();
	if (qc.measure1) qint.eB.not();
	qint.eB.hadamard();
If we want, we can clean up so it's easier to look at...
	qint.alice.write(0); qint.eA.write(0);