| Andrew Cooke | Contents | Latest | RSS | Twitter | Previous | Next

C[omp]ute

Welcome to my blog, which was once a mailing list of the same name and is still generated by mail. Please reply via the "comment" links.

Always interested in offers/projects/new ideas. Eclectic experience in fields like: numerical computing; Python web; Java enterprise; functional languages; GPGPU; SQL databases; etc. Based in Santiago, Chile; telecommute worldwide. CV; email.

Personal Projects

Lepl parser for Python.

Colorless Green.

Photography around Santiago.

SVG experiment.

Professional Portfolio

Calibration of seismometers.

Data access via web services.

Cache rewrite.

Extending OpenSSH.

Last 100 entries

Real-life Financial Co Without ACID Database...; Flexible Muscle-Based Locomotion for Bipedal Creatures; SQL Performance Explained; The Little Manual of API Design; Multiple Word Sizes; CRC - Next Steps; FizzBuzz; Update on CRCs; Decent Links / Discussion Community; Automated Reasoning About LLVM Optimizations and Undefined Behavior; A Painless Guide To CRC Error Detection Algorithms; Tests in Julia; Dave Eggers: what's so funny about peace, love and Starship?; Cello - High Level C Programming; autoreconf needs tar; Will Self Goes To Heathrow; Top 5 BioInformatics Papers; Vasovagal Response; Good Food in Vina; Chilean Drug Criminals Use Subsitution Cipher; Adrenaline; Stiglitz on the Impact of Technology; Why Not; How I Am 5; Lenovo X240 OpenSuse 13.1; NSA and GCHQ - Psychological Trolls; Finite Fields in Julia (Defining Your Own Number Type); Julian Assange; Starting Qemu on OpenSuse; Noisy GAs/TMs; Venezuela; Reinstalling GRUB with EFI; Instructions For Disabling KDE Indexing; Evolving Speakers; Changing Salt Size in Simple Crypt 3.0.0; Logarithmic Map (Moved); More Info; Words Found in Voynich Manuscript; An Inventory Of 3D Space-Filling Curves; Foxes Using Magnetic Fields To Hunt; 5 Rounds RC5 No Rotation; JP Morgan and Madoff; Ori - Secure, Distributed File System; Physical Unclonable Functions (PUFs); Prejudice on Reddit; Recursion OK; Optimizing Julia Code; Cash Handouts in Brazil; Couple Nice Music Videos; It Also Works!; Adaptive Plaintext; It Works!; RC5 Without Rotation (2); 8 Years...; Attack Against Encrypted Linux Disks; Pushing Back On NSA At IETF; Summary of Experimental Ethics; Very Good Talk On Security, Snowden; Locusts are Grasshoppers!; Vagrant (OpenSuse and IDEs); Interesting Take On Mandela's Context; Haskell Cabal O(n^2) / O(n) Fix; How I Am 4; Chilean Charity Supporting Women; Doing SSH right; Festival of Urban Intervention; Neat Idea - Wormholes Provide Entanglement; And a Link....; Simple Encryption for Python 2.7; OpenSuse 13.1 Is Better!; Little Gain...; More Details on Technofull Damage; Palmrest Cracked Too....; Tecnofull (Lenovo Support) Is Fucking Useless; The Neuroscientist Who Discovered He Was a Psychopath; Interpolating Polynomials; Bottlehead Crack as Pre-amp; Ooops K702!; Bottlehead Crack, AKG K701; Breaking RC5 Without Rotation; Great post thank you; Big Balls of Mud; Phabricator - Tools for working together; Amazing Julia RC5 Code Parameterized By Word Size; Chi-Square Can Be Two-Sided; Why Do Brits Accept Surveillance?; Statistics Done Wrong; Mesas Trape from Bravo; European Report on Crypto Primitives and Protocols; Interesting Omissions; Oryx And Crake (Margaret Atwood); Music and Theory; My Arduino Programs; Elliptic Curve Crypto; Re: Licensing Interpreted Code; Licensing Interpreted Code; ASUS 1015E-DS03 OpenSuse 12.3 SSD; translating lettuce feature files into stub steps files; Re: translating lettuce feature files into stub steps files; A Tale of Two Psychiatrists; The Real Reason the Poor Go Without Bank Accounts

© 2006-2013 Andrew Cooke (site) / post authors (content).

Copies of Light

From: "andrew cooke" <andrew@...>

Date: Thu, 8 Feb 2007 21:06:18 -0300 (CLST)

There's a summary at the BBC -
http://news.bbc.co.uk/2/hi/science/nature/6343311.stm - but the Nature
news article has a lot more info -
http://www.nature.com/news/2007/070205/full/070205-8.html

There's also an article at the Harvard site -
http://www.news.harvard.edu/gazette/2007/02.08/99-hau.html

Since I think Nature deletes or paywalls articles after a certain time,
here's a couple of selections from their text:

"First, they slow a light pulse  travelling, naturally, at the speed of
light  to a crawl by beaming it into an ultracold cloud of about two
million sodium atoms. Then they destroy the light beam entirely, but
imprint a memory of it in the sodium.

They shunt some of these atoms into a second cloud, and tickle them with
another laser beam. This triggers their 'memory' of the original pulse,
which emerges, much weaker but otherwise unchanged, from the second
cloud."

[...]

"The experiment relies on the way that, according to quantum mechanics,
atoms may behave as waves as well as particles. This enables atoms to do
some counterintuitive things, such as passing through two openings at
once.

Usually, each atom displays its wavelike behaviour independently of all
its neighbours, like a crowd of soccer fans each waving their arms about
at random. But if a group of atoms is cooled to very low temperatures  a
mere fraction of a degree above absolute zero  then they may all come
into step, like the fans conducting a Mexican wave.

In this state, called a Bose-Einstein condensate, information encoded in a
light pulse can be transferred to the atom waves. Because all the atoms
move coherently, the information doesn't dissolve into random noise and
get lost."

[...]

"At the same time, the light's momentum is transferred to the atoms, so
they move out of the Bose-Einstein condensate cloud to a second, similar
cloud that the researchers hold suspended in a magnetic trapping field
less than a millimetre away.

By turning the control beam on this second cloud, the added atoms are
encouraged to spread their 'message' throughout the whole cloud. All the
atoms come into step with each other again, giving this second cloud a
memory of the original laser pulse. They then re-radiate this pulse,
albeit with only about one-fiftieth as much of the original light energy.
The pulse crawls through the second cloud and speeds up once it leaves."

Andrew

Comment on this post