Archive for August, 2007

Astronomy v particle physics

Tuesday, August 14th, 2007

The traditional realm of astronomy is the observation and study of the largest objects in the Universe, while the traditional domain of high-energy physics is the study of the smallest things in nature. But these two sciences concerned with opposite ends of the size spectrum are…bound fast by a thousand invisible cords that cannot be broken.

So says Rocky “Southpaw” Kolb at The Kavli Institute for Cosmological Physics in Chicago, in a lovey-dovey essay called “A Thousand Invisible Cords Binding Astronomy and High-Energy Physics”.

Southpaw Kolb wants more a-huggin and a-kissin when astronomers and particle physicists get together.

Ain’t nothing wrong with that. But which is better: astronomy or particle physics? In a celebrity smackdown, who’d be holdin the golden belt at the end of the fight?

No question in mah mind that particle physics would get its butt kicked well and good.

Astronomy is a-jivin and a-thrivin. It’s been a platinum-plated golden age for astrofreaks since Hubble first peered into the gloom. And there’s no sign of a slowdown.

But particle physics, it’s been a-lurchin and a-staggerin in sloth and crisis ever since the particle people found they’d be at a loose end for four years after LEP shutdown and until the LHC started up. That’s four years with ya feet up. They gotta be seriously outta shape.
And what about new blood? What kinda sadist would train to be particle person without no particles to play with?

If ya’ll want to see a discipline in the doldrums, look no further than particle physics.

But in the spirit of the 60s (which they all remember as their own golden age), we still lurv particle people anyway.

Ref: arxiv.org/abs/0708.1199:A Thousand Invisible Cords Binding Astronomy and High-Energy Physics

Quantum dilemmas

Monday, August 13th, 2007

Ya wake up in the cells, your head a-boomin and a-thumpin. An officer helps loosen ya tongue, Guantamo style, and before ya even had breakfast, he’s a-shoutin and a-rantin for a confession.

There’s even a deal on the table. Rat on ya buddy in the next cell and the judge’ll cutcha some slack. Keep schtum and both of youse’ll go down together.

Ya’ll been there–the prisoner’s dilemma. And ya’ll know the best strategy is to rat on ya buddy and let him rot in jail. It ain’t nothing personal.

Now Anton “Beam-me-up, Scotty” Zeilinger at the University of Vienna has a better idea. He’s gone and created a quantum version of prisoner’s dilemma using an optical quantum computer.

In quantum prisoner’s dilemma, entanglement introduces an element of co-operation whether ya want it or not. So ratin on ya buddy gives ya no benefit over co-operatin with the cops.

This ain’t the first time anybody’s gotten all quantum with a prisoner. Jiangfeng Du and his buddies at the University of Science and Technology of China nailed a similar trick using NMR a few years ago.

But it does look like a cool way to show off the buffed-up chrome and fancy wing mirrors on Anton’s latest quantum computer. And it’ll help him and his buddies no end when Friday nite’s a-rompin and a-ruttin turns sour.

Ref: arxiv.org/abs/0708.1129: Experimental Realization of a Quantum Game on a One-way Quantum Computer

Why does the wine glass sing?

Sunday, August 12th, 2007

Ah know ya’ll like a tipple or two. Who don’t? So ya’ll know how a-strokin and a-rubbin a wet finger on a wine glass can put some sounds up.

Now Oleg “Chaser” Kirillov at Moscow State Lomonosov University says we ain’t got no ah-dear how this process of sound generation works. And to clarify things for ya’ll, he’s worked out how it occurs by considerin “a gyroscopic system with two degrees of freedom under the action of small dissipative and non-conservative positional forces, which has its origin in the models of rotating bodies of revolution being in frictional contact.

Apparently friction causes the glass to resonate at a frequency that generates sound (doh!).

Chaser Kirrolov says that if ya’ll have disc breaks that are a-squealin and a-screechin, then the same effect is to blame.

But heads up, Chaser: what we need to know is not what makes ‘em squeal, but what’ll make ‘em stop.

Ref: arxiv.org/abs/0708.0967: How to Play a Disc Brake

A loophole in quantum cryptography

Saturday, August 11th, 2007

I ain’t gonna stick my neck out on this but Peter “Raptor” Rapcan has something a-boilin and a-bubblin over at the Slovak Academy of Sciences which could send all youse quantum cryptographers a-scuttlin back to your theory books.

When ya’ll measure the state of a quantum particle, I betcha that ya’ll expect the information about that state to be destroyed by the process of measurement. But Raptor Rapcan ain’t so sure.

His thinkin goes like this. All the information about the particle is stored in the wavefunction. But there are well established ideas about how much information a single measurement can extract from a wave-function–and it ain’t much. Could a second observer extract more about the original state?

Raptor Rapcan and his Slovak buddies seem to think so and suggest this could compromise the security of any information sent in this way.

In the paper, “Recycling of quantum information: Multiple observations of quantum systems” they investigate the amount of information that can be extracted from a quantum system by a sequence of observers who are not allowed to communicate.

And to cut a long story short, Raptor says that when measured like this, quantum information stored in an ensemble of quantum particles behaves classically.

Woah–classically! I guess that’s gonna change the goalposts in the micro v macroscopic physics stakes. Ya’ll know how secure classical information is-right? This is gonna leave a few cryptos a-sweatin and a-mumblin.

Reference: arxiv.org/abs/0708.1086: Recycling of Quantum Information: Multiple Observations of Quantum Systems