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Hamish Johnston: October 2008 Archives

By Hamish Johnston

Pure knowledge isn’t enough these days and physicists often feel pressured to justify their work in terms of “practical applications”. You would think that dark-matter researchers would find this particularly difficult, given the esoteric nature of the stuff that they are looking for, but Leo Stodolsky at MPI-Munich begs to differ.

He has posted an article on the arXiv preprint server outlining how biology and materials science have benefitted from dark matter research in very different ways.

The former is the more straight forward application. Cryodetectors — developed to measure the tiny amounts of energy that dark-matter particles could impart to conventional matter — have been used to boost the sensitivity of mass spectrometers used to study large biological molecules.

The latter application is much more bizarre. In the early days of the CRESST dark matter search, strange signals were observed in the sapphire detector crystals. It turned out that the crystals were clamped too tightly and were cracking. However, because the detector was so sensitive, the signals represent some of the best data ever on microfractures — leading to a better understanding of this process.

The CRESST website also has a page describing these two applications.

By Hamish Johnston

If you are like me and you struggle with the basics of quantum computing you might want to stop reading now because this blog entry is about “quantum robotics”.

According to Daoyi Dong and colleagues at the University of Science and Technology of China, “A quantum robot is essentially a complex quantum system which generally consists of three fundamental components: multi-quantum computing units (MQCU), quantum controller/actuator, and information acquisition units”.

And they should know, because they have just published a preprint that “proposes a brand-new paradigm of robots”.

So why would you want a quantum robot?

According to Dong and Co, they are better at learning than classical robots because they would use “quantum reinforcement learning algorithms”.

Of course, physicists are still struggling to make a just one practical quantum computing device, let alone a MQCU. So I’m guessing that you might have to wait a while for a robot that uses quantum mechanics to learn how to iron your shirts.

UPDATE 27 October: This preprint has been withdrawn by the authors.

su.jpg Huai Su’s fractal calligraphy

By Hamish Johnston

In the scientific world, fractals were first identified in the mid-1970s by the mathematican BenoƮt Mandelbrot.

However, it’s possible that artists and artisans have long been using the fragmented shapes in their work.

In 1999, two Australian physicists famously showed that the “paint-drip” canvasses of Jackson Pollock could be dated by computing their fractal dimension — which tended to increase as Pollock matured as an artist.

Now, Yuelin Li of Argonne National Lab in the US has posted a paper on the arXiv preprint server claiming that calligraphy done by the “maniac Buddist monk” Huai Su more than 1200 years ago contains fractals. Li analysed a request for “bitter bamboo shoots and tea” written by the monk and found that it can be characterized by two different fractal dimensions.

Li believes that the fractal nature of some artworks “can be attributed to the artist’s pursuit of the hidden order of [the] fractal”.

hawking.jpg
(Credit: Stewart Francis)

By Hamish Johnston

Would you get the face of your favourite physicist tattooed on your leg?

Jack Newton spent six hours getting a portrait of cosmologist Stephen Hawking emblazoned on his leg after reading the physicist’s popular tome A Brief History of Time — according to the UK paper Metro.

Newton — 23 and apparently no relation to Hawking’s distant predecessor at Cambridge — admits that he didn’t understand Hawking’s book, but respected the 66-year old physicist.

By Hamish Johnston

Have you ever wondered what would happen if you dropped a sphere of jelly on floor?

The answer to this and other pressing questions in fluid dynamics have appeared on the arXiv preprint server as a series of videos that have been submitted to the Gallery of Fluid Motion — part of next month’s American Physical Society Division of Fluid Dynamics meeting .

In the movie I watched, drops of “viscoelastic” material — mixtures of gelatin and water — pancake onto the floor before rising phoenix-like back into the air.

But instead of coming back as a sphere, the jelly rises as a slowly-vibrating dumbell.

This particular video was posted by Federico Hernandez-Sanchez and colleagues at the National University of Mexico and you can read about their experiment here — where you can also link to their videos.

Other papers linking to videos include Dynamics of Water Entry, The Clapping Book, and Liquid Acrobatics .

knots.jpg
Some of Raymer and Smith’s knots — prepare yourself to laugh and then think. (Courtesy: UCSD).

By Hamish Johnston

Call me a killjoy, but I don’t find this year’s Ig Nobel prize in physics particularly amusing. It certainly doesn’t live up to to the award’s mandate of highlighting “Research that makes people LAUGH and then THINK”.

I didn’t laugh at Dorian Raymer and Douglas Smith’s study of why knots form spontaneously in lengths of “agitated” string — which won them this year’s prize, and seems like a perfectly reasonable, even practical topic.

And all I could think was “I’m sure this sort of work has been done before”.

So I typed “knot” into our site search engine and sure enough this article came up. Now I’m no string theorist, but it looks like Jens Eggers at the University of Bristol published a similar study a year before Raymer and Smith. I tried to call Eggers to see if he was miffed about being passed over for the Ig Nobel, but there was no answer. I guess he was all tied up!

nobel.jpg
(Courtesy: Nobel Foundation).

By Hamish Johnston

The 2008 Nobel Prize for Physics is set to be announced at 10.45am BST on Tuesday 7 October and we are starting to get excited here at Physics World about who will scoop this year’s gong.

Here are a few of our picks…

News Editor Michael Banks is putting his money on Daniel Kleppner at MIT for inventing the hydrogen maser.

Reporter Jon Cartwright is tipping Berkeley’s Saul Perlmutter and Brian Schmidt at the Australian National University for their discovery that the universe’s rate of expansion is increasing…leading to the concept of dark energy.

underwater.jpg
Artist’s impression of a possible KM3NeT detector configuration. (Courtesy: ASPERA).

By Hamish Johnston

In July 2007 Europe’s astroparticle physicists drew up a wish list of research projects that they would like to see funded.

Dubbed the “Magnificent Seven” by ASPERA — a consortium of national agencies that fund astroparticle physics research — the projects aim to answer the fundamental questions facing astroparticle physicists.

This wish list has been through the wringer of European consulation processes and earlier this week a final roadmap document was released. It’s a 61-page report and you can find the PDF here .

The document recommends that seven projects be supported by European funding agencies , and gives three projects “priority” status.

These three are the Cherenkov Telescope Array (CTA) for detecting of cosmic high-energy gamma rays; KM3NeT, a cubic kilometre-scale neutrino telescope in the Mediterranean Sea; and the Pierre Auger North array for the detection of charged cosmic rays.

By Hamish Johnston

Yesterday I had the pleasure of attending day two of “Pendry Fest”, a series of lectures at Imperial College given in honour of the physicist Sir John Pendry, who recently turned 65.

Pendry is probably most famous for his prediction in 2000 of the negative refraction of electromagnetic radiation by new manmade materials called metamaterials. This was confirmed experimentally by Duke University’s David Smith, who spoke yesterday, and Pendry and Smith went on to use this property of metamaterials to create an invisibility cloak in 2006.

Although making such metamaterials is a significant challenge of electrical engineering, Pendry realized that the physics could be described rather elegantly by borrowing ideas from Einstein’s general theory of relativity — a concept he dubbed “Transformation Optics”. Indeed, in his talk Smith credited Pendry with encouraging a generation of electrical engineers to read-up on general relativity.

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