Quantum computing


As you can see from old "wayback" snapshots this stuff has been around for more than 15 years and is getting mostly a little dated. What with various issues including file removals at the ISP where my pages are hosted, some of it has been lost and I really don't expect to get around to replacing it. Sorry. Too bad.

Very basic QC simulator

BEWARE: This is a very rough rolled-it-myself package! But it is capable of doing things like writing QC-runnable TTT players, Sudoko solvers, and a few other tricks.

Zipfile of UNIX/Linux sources

Update 2009: QCC v1.21 is now running on a Radeon 3800 GPU at around 200 GF. This represents a 10x speedup over a 3 GHz Core2 duo. Since the platform is still very experimental I expect another 2x-10x speedup is in the offing -- the card represents a 1 TF processor, after all.

Update 2010:QCC v2.1 is now running at 3 TF on a $300 USD desktop machine, simulating a chess player. At present the code still runs slowly and can not beat GNU Chess reliably. But I have high hopes! :)

Update 2015: QCC has been binned and completely new code developed. A chess playing 256-qubit QC sim is now running reasonably quickly -- a few mins per move on my current ancient desktop -- and beating gnuchess, GreKo and even crafty every now and again. Game files are around hereabouts and could be played on your local xboard if you have a suitable platform.

Simulated QC playing various board games

I have a simulated 22-qubit TTT player that takes < 1 sec per move on a slow desktop box and appears to play "perfectly". Download here.
I also have a hare&hounds (AKA fox&hounds) simulated 36-qubit QC that makes (hopefully) "perfect" moves in about 5 mins on a 3 GHz desktop. A somewhat faster version written in CUDA takes about 5 sec per move. Download here.
Development of my very weak QC chess player continues. :)

Quantum computation: a tutorial

A fine introduction to most areas of research, how they fit together, and how QC might be used to solve some problems exponentially faster than on conventional hardware.

The Kitchen Sink: Quantum Computing (VT.EDU)

In 1982 Prof. Richard P. Feynman flipped the tables on the relationship between physics and computers by asking not what can computers do for physics, but rather what can physics do for computers. Instead of spending so much time and effort performing quantum mechanical calculations with computers based on classical dynamics, why not design a computer that uses inherently quantum dynamics? This site is devoted to the dissemination of knowledge gained in the past 15 or so years of research in this field. Any new submissions or ideas are welcome and encouraged.

Physics of Computation (handbook entry, LCS.MIT.EDU)

Our current research into the Physics of Computation is the continuation of a long and productive train of research that our group has been involved in for over 15 years. This research produced many of the original results on the theory of reversible computation (including reversible cellular automata), and has more recently included pioneering work on lattice gas simulations of physics and results on Quantum Computation.

Two talks by Seth Lloyd at MIT

Seth Lloyd (from the Santa Fe Institute) gave the opening talk in the Physics of Computation series at MIT last June ("A Technologically Feasible Quantum Computer"). This page notes 2 other talks, entitled "A novel architecture for computation at the nanoscale" and "From Quantum Computers to Acoustic Refrigerators: The Role of Information in Physical Systems".
[this one brought to my attention by David P. Rabahy <RABAHY@amcfac.enet.dec.com>]

Quantum measurements and the Abelian Stabilizer Problem by A. Yu. Kitaev

We present a polynomial quantum algorithm for the Abelian stabilizer problem which includes both factoring and the discrete logarithm. Thus we extend famous Shor's results [7]. Our method is based on a procedure for measuring an eigenvalue of a unitary operator. Another application of this procedure is a polynomial quantum Fourier transform algorithm for an arbitrary finite Abelian group. The paper also contains a rather detailed introduction to the theory of quantum computation.

Quantum Automata and Quantum Grammars by C. Moore & J. P. Crutchfield

To study quantum computation, it might be helpful to generalize structures from language and automata theory to the quantum case. To that end, we propose quantum versions of finite-state and push-down automata, and regular and context-free grammars. We find analogs of several classical theorems, including pumping lemmas, closure properties, rational and algebraic generating functions, and Greibach normal form. We also show that there are quantum context-free languages that are not context-free.
[Also seems to be copy at Quantum Automata and Quantum Grammars]

Reversible Logic

The relatively new branch of science called the Physics of Computation attempts to address the limits of computing devices. The relationship between information processing and energy dissipation has been explored by the likes of Rolf Landauer and Charles H. Bennett.
[this one brought to my attention by David P. Rabahy <RABAHY@amcfac.enet.dec.com>]

General Bibliography on Quantum Computing (started from local copy of <http://eve.physics.ox.ac.uk/Articles/QC.Articles.html>).

Synopsis of recent and relevant articles in Science (thanks to J. K. Braswell for this one).

Research groups involved in atom trapping

IBM Quantum information and quantum computation

Oxford Quantum Information Home Page

[Sees to have moved here].

ANU Quantum computing course home page

UCLA Particle Beam Physics Laboratory Quantum Information Page


Theory work on quantum computation/cryptography at Los Alamos

Quantum Information Theory

Quantum Information Page (at UCLA Physics)

YQFP Research Group: Quantum Measurements and Quantum Computers

Many-Worlds Quantum Theory

The Quantum Coupled Architecture Home Page



Computer Science Technical Reports at Exeter

Qgol - a system for simulating quantum computation: Theory, Implementation and Insights by Greg Baker

Molecular Computing and Nanotechnology Center Designing Nano-scale Structures and Devices for Intelligent Applications

A Bibliography of Quantum Cryptography by Gilles Brassard

[seems to have moved here].

Evidence supporting quantum information processing in animals

Overview of the New Physics

Seeing into the Quantum World by Randall Graham, Science Writer

Other random notes & snippets from here & there

Kym Horsell /

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