Tuesday, 20 February 2007

What's in a name?

See the titles of these papers that I found in this thread on PhysicsForums and decide yourself:

Would Bohr be born if Bohm were born before Born?
H. Nikolic

IIB or not IIB
Mark Srednicki

If anyone knows papers with interesting names, please feel free to say it.


I'm adding two more. One, Osame pointed me (as you can see in the comments), the other I was browsing some papers I collected some time ago and stumbled with it. I guess both can be considered in the same class of the second one above, let us say, Shakespearean Titles:

What's in a name?
Luciano da Fontoura Costa

Much Ado About Nothing
Vijay Balasubramanian, Klaus Larjo, Joan Simon

Picture: Romeo and Juliet, by Soul-Daemon.

Friday, 16 February 2007

Quantum Computers... so fast?

Last edition: 20/02/2007. I'm adding some links to the scientific terms.
Nobody (I mean, physicists) was expecting a commercial quantum computer so fast, but the firm D-Wave, founded by physicist Geordie Rose (who has his own blog) in 1999, claims that achieved just that.

Risking being repetitive, quantum computation becomes an attractive endeavour after P.W. Shor demonstrated in his paper Polynomial-Time Algorithms for Prime Factorization and Discrete Logarithms on a Quantum Computer. As prime factorization is a key element in todays public key cryptographic schemes because it is an NP problem for classical computers, i.e. the time necessary to factorize a prime number scales exponentially with the size of the number, a polynomial time algorithm, turning it into what is called a P problem, means a break down of our current electronic security.

Now, quantum computers are very elusive and that's because they relie on entanglement of quantum systems to make the miracle of transforming an NP problem into a P problem. More detailed explanations can be found in the book Quantum Computation and Information or in some sites in the internet:

The Quantum Computer, An Introduction by Jacob West
Lectures on Quantum Computers by David Deutsch
Quantum Computation. Mini-Course, by André Berthiaume

It is difficulty, although, to keep entanglement for a sufficient time to do any useful calculation, for entanglement is quickly lost as it is impossible to avoid interactions with the environment which causes entanglement to fade. D-Wave has just claimed it was successful in doing this for 16 qubits, which is a quantity of information that is already interesting.

Most of physicists, including me, are skeptical about that because D-Wave haven't released to much information about how the computer works and, as groups around the world have been trying it with a lot of different techniques without great results until now, it is surprising that they've achieved it so fast. Anyway, it would really be something exciting if they do that. Let us wait.

While you wait, a press release on PhysicsWeb

Firm claims first "commercial" quantum computer

and a YouTube video of D-Wave's presentation

Picture: taken from The Economist.

PS: I intend to edit this post a little more, adding some links, but I don't have too much time today and I'll do that during the next days.

Tuesday, 13 February 2007

Ferrofluid Video

As written in the Wikipedia:

"A ferrofluid is a liquid that becomes strongly polarised in the presence of a magnetic field. Ferrofluids are composed of nanoscale ferromagnetic particles suspended in a carrier fluid, usually an organic solvent or water."

This is a nice video I found in YouTube showing experiments dealing with shape manipulation of a ferrofluid by a magnetic field. Very beautiful. If you cannot see the image link below, just click here.

Picture: taken from the Ferrofluid entry on Wikipedia linked in the text above.

Monday, 12 February 2007

Darwin's Day

Today is Darwin's Day. He was born in this day in the year of 1809 and published The Origin of Species in 1859.

Picture: taken from Wikipedia's link to Charles Darwin.