Thursday, October 19, 2006

Invisibility Lattice

Researchers at Duke University and Imperial College have created the world's first "cloaking device", a metamaterial ring that hides a copper piece from detection by microwaves. While still a far cry from the fictional technology known to Star Trek fans, this is the first experimental demonstration that metamaterials with a negative index of refraction can in fact be used to obtain this kind of effect (which had been theoretically predicted).

A metamaterial is a lattice-like arrangement of structures that acts like a material with electromagnetic properties not found in conventional materials (no, they have nothing to do with lattice QCD at all, but I liked the catchy caption). A negative index of refraction occurs in metamaterials whose effective electric permittivity ε and the magnetic permeability μ are both negative; in this case, the refractive index n=ε1/2μ1/2 becomes negative, and waves are refracted the opposite way as usual. For more on this pretty interesting stuff, see here and here, or (for people with appropriate subscriptions) here.

Tuesday, October 17, 2006

Nobel Prize Winning Opera Singer

2004 Nobel Prize winner Frank Wilczek has started a new career as an opera singer, starring in the mini-opera "Atom & Eve" (no, not this one, but this one) at the 2006 Alpbach Technology Conference.

The opera tells the love story between Atom, the lonely oxygen atom, and Eve, the atomic physicist, whose rather significant scale disparity causes a few problems that are finally overcome by means of Bose-Einstein condensation which allows Atom to exist on a macroscopic scale. Apparently the libretto as performed differed from the one linked to above in having a happy ending. And, according to Physik Journal, Wilczek has already set his sight on the next great prize to win: a Grammy.

Tuesday, October 10, 2006

On Being Wrong

It appears I was wrong in my assessment of the relative probabilities of nuclear war in the Cold War era and at the present time. The news that the most unpredictable leader in the world appears to have nuclear weapons is very bad news indeed. That the powers that have to deal with the problem are communist China and Bush's US, doesn't make me feel any better about it. Of course, I don't really know what they should do, anyway. There is this little piece in my guts that says "Nuke them before it is too late", but that is such a ludicrously right-wing position that it has to be my appendix speaking, and I wouldn't really want to listen to political advice given by an organ which is only vestigial in humans.

And no, this is not going to turn into another political punditry blog; I just think a scientist is under an obligation to point out their own errors. A fine example of this scientific responsibility was given by Penny Smith, who recently withdrew her announced solution to the Navier-Stokes Millennium Problem due to a crucial flaw in the proof. Admitting to being wrong on such a big and well-known mathematical problem must be immensely painful, especially after it received a lot of premature publicity, but ultimately this is what distinguishes Science from other, less honest, human endeavours such as business or politics. So let us wish her the best success in her efforts to patch up the holes in her proof, if possible.

Tuesday, October 03, 2006

Physics Nobel Prize 2006

The 2006 Nobel Prize in Physics goes to John C. Mather and George F. Smoot "for their discovery of the blackbody form and anisotropy of the cosmic microwave background radiation".

The award honours the achievements of the COBE (COsmic Background Explorer) mission, which was the first to measure the anisotropies in the cosmic microwave background radiation (for the discovery of which Penzias and Wilson were awarded the 1978 Nobel Prize). The cosmic microwave background (CMB for short) is the light emitted by the gas in the young (about 300,000 years after the Big Bang) universe when it had cooled down far enough for atoms to form (to about 3000 Kelvin), making it transparent for light for the first time. The expansion of the universe since then has caused the light emitted then to shift its wavelength to the microwave range by today (about 14,000,000,000 years after the Big Bang), causing it to look like that of a black body of temperature 2.728 Kelvin. In fact, one of the achievements honoured by the award is the demonstration that the measured CMB spectrum is the best fit to a perfect blackbody spectrum ever seen. The other achievement being honoured is the measurement of the tiny anisotropies in that background which were caused by density fluctuations in the primordial gas, which later would form galaxies and stars through gravitational collapse. This work has had a huge impact on our understanding of the early history of the universe. A more detailed study of the CMB is being done by WMAP, which also has made huge contributions to our understanding of the history and composition of the universe (so who knows, maybe there will be another Nobel Prize for CMB explorers in the future).

More about this from Backreaction, Dave Bacon, Cosmic Variance, Clifford Johnson, Andrew Jaffe, Rob Knop, Chad Orzel, Steinn SigurĂ°sson or the conventional media.