Monthly Archives: December 2011

Quelle drag! McGill research team develops tiny (150 atoms) electronic circuits

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Drag and heat—sounds like a car race, doesn’t it? It’s all about electronics and some nanoscale work by researchers at McGill University (Montréal, Canada). From the Dec. 7, 2011 McGill news release,

A team of scientists, led by Guillaume Gervais from McGill’s Physics Department and Mike Lilly from Sandia National Laboratories, has engineered one of the world’s smallest electronic circuits. It is formed by two wires separated by only about 150 atoms or 15 nanometers (nm).

The paper is available behind Nature’s paywall or you can view the abstract for Positive and negative Coulomb drag in vertically integrated one-dimensional quantum wires. Excerpted from the abstract,

Electron interactions in and between wires become increasingly complex and important as circuits are scaled to nanometre sizes, or use reduced-dimensional conductors such as carbon nanotubes, nanowiresand gated high-mobility two-dimensional electron systems. This is because the screening of the long-range Coulomb potential of individual carriers is weakened in these systems, which can lead to phenomena such as Coulomb drag, where a current in one wire induces a voltage in a second wire through Coulomb interactions alone.

The  news release addresses the Coulomb drag in more accessible (for some of us) language,

This is the first time that anyone has studied how the wires in an electronic circuit interact with one another when packed so tightly together. Surprisingly, the authors found that the effect of one wire on the other can be either positive or negative. This means that a current in one wire can produce a current in the other one that is either in the same or the opposite direction. This discovery, based on the principles of quantum physics, suggests a need to revise our understanding of how even the simplest electronic circuits behave at the nanoscale.

In addition to the effect on the speed and efficiency of future electronic circuits, this discovery could also help to solve one of the major challenges facing future computer design. This is managing the ever-increasing amount of heat produced by integrated circuits.

According to the news release, this discovery could have an impact on a wide range of electronics including smartphones, desktop computers, televisions, and GPS systems. Congratulations to the McGill team: D. Laroche, G. Gervais, M. P. Lilly, and J. L. Reno.

Halleluiah! one step closer to self-cleaning glass

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I cannot tell you the joy this news gives me. From the Dec. 6, 2011 news item on Nanowerk,

Eyeglasses need never again to be cleaned, and dirty windscreens are a thing of the past! Researchers at the Max Planck Institute for Polymer Research in Mainz and the Technical University Darmstadt are now much closer to achieving this goal. They have used candle soot to produce a transparent superamphiphobic coating made of glass (“Candle Soot as a Template for a Transparent Robust Superamphiphobic Coating”). Oil and water both roll off this coating, leaving absolutely nothing behind. Something that even held true when the researchers damaged the layer with sandblasting. The material owes this property to its nanostructure. Surfaces sealed in this way could find use anywhere where contamination or even a film of water is either harmful or just simply a nuisance.

Actually, I’m hoping for a little more than eye glasses—I never want to wash another window or mirror. More from the news item,

The coating essentially consists of an extremely simple material: silica, the main constituent of all glass. The researchers coated this with a fluorinated silicon compound, which already makes the surface water and oil repellent, like a non-stick frying pan. The really clever part is the structure of the coating, however. This is what makes the glass super water repellent and super oil repellent. In a frying pan with this type of coating, water and oil would simply roll around in the form of drops. The structure of the layer resembles a sponge-like labyrinth of completely unordered pores, which is made up of tiny spheres.

Such a coating would be ideal for numerous applications, not least because it is so easy to produce. “We can even produce it in jam jars,” says Doris Vollmer [head of a research group at the Max Planck Institute for Polymer Research]. And the soot from a candle flame, from which the researchers made something akin to a glass imprint, served as the model for the porous structure of the spheres. The researchers began by holding a glass slide in a flame so that the soot particles, which measure around 40 nanometres in diameter, formed a sponge-like structure on the glass. The next step was to coat it with silica in a glass vessel – even a jam jar would do – by vapour depositing a volatile organic silicon compound and ammonia onto the soot deposit. When they subsequently heated the material, the soot decomposed. The next step was to vapour deposit a fluorinated silicon compound as well onto the hollow silica structure.

They then attempted to wet this coating with different liquids. However, they didn’t succeed, even when they let hexadecane drip from a great height onto it; in a non-stick frying pan, hexadecane spreads out like water in a washbasin. “Initially, a drop of the oil penetrated into the sponge-like structure, but then bounced back like a rubber ball,” explains Doris Vollmer. Although a portion of the liquid remained in the pores and wet the material, when most of the drop returned to the surface at a slower speed after bouncing up, it drew the small amount of the hexane that had remained out of the glass pores again. Finally, the reunited drop remained lying on the surface like a ball. The researchers in Mainz tested the superamphiphobic layer with a total of seven liquids and found that none was sucked up by the glass sponge.

Sadly, it seems I will have to wait a bit longer as there is no mention of a product being commercialized now or in the near future.

Thailand, nanotechnology, and natural disaster relief

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Nanotech 2012 in Japan will serve as a platform for Thailand’s natural disaster mitigation business and partnership initiatives. From the Dec. 6, 2011 news item on Nanowerk,

The National Center for Nanotechnology (NANOTEC) has decided to use the upcoming nanotech 2012 in Tokyo, Japan as a platform to share, exchange knowledge, and seek business partnership in natural disaster mitigation under the theme “Thailand: Nanotechnology for Natural Disaster Mitigation” from February 15-17 in Tokyo Big Sight.

“The recent flooding in Thailand according to the Disaster Prevention and Mitigation Department is the worst case in over 50 years” said Prof. Sirirurg Songsivilai, Executive Director of NANOTEC. “The more than three- month flooding has claimed the lives of 602 people and affecting more than 13 million, or one in every five Thais”.

They will be looking to establish partnerships and discuss opportunities. From news item,

At nanotech 2012, NANOTEC will showcase 6 research topics related to natural disaster mitigation:

1. Clean Water

2. Mosquito repellent

3. Leptospirosis test kit

4. nSack as replacement for sand bags

5. nClean products for use in Big-Cleaning Day activities

6. nGuard for air-conditioned filtration

I imagine a lot of interest from the Japanese in these technologies given the natural and other disasters they too have suffered this year.  According to the home page for Nanotech 2012, this year’s exhibition (Feb. 15-17, 2012) will take place despite the recent earthquake in east Japan.

Entangling diamonds

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Usually when you hear about entanglement, they’re talking about quantum particles or kittens. On Dec. 2, 2011, Science magazine published a paper by scientists who had entangled diamonds (that can be touched and held in human hands). From the Dec. 1, 2011 CBC (Canadian Broadcasting Corporation) news article by Emily Chung,

Quantum physics is known for bizarre phenomena that are very different from the behaviour we are familiar with through our interaction with objects on the human scale, which follow the laws of classical physics. For example, quantum “entanglement” connects two objects so that no matter how far away they are from one another, each object is affected by what happens to the other.

Now, scientists from the U.K., Canada and Singapore have managed to demonstrate entanglement in ordinary diamonds under conditions found in any ordinary room or laboratory.

Philip Ball in his Dec. 1, 2011 article for Nature magazine describes precisely what entanglement means when applied to the diamond crystals that were entangled,

A pair of diamond crystals has been linked by quantum entanglement. This means that a vibration in the crystals could not be meaningfully assigned to one or other of them: both crystals were simultaneously vibrating and not vibrating.

Quantum entanglement — interdependence of quantum states between particles not in physical contact — has been well established between quantum particles such as atoms at ultra-cold temperatures. But like most quantum effects, it doesn’t tend to survive either at room temperature or in objects large enough to see with the naked eye.

Entanglement, until now, has been demonstrated at very small scales due to an issue with coherence and under extreme conditions. Entangled objects are coherent with each other but other objects such as atoms can cause the entangled objects to lose their coherence and their entangled state. In order to entangle the diamonds, the scientists had to find a way of dealing with the loss of coherence as the objects are scaled up and they were able to achieve this at room temperature. From the Emily Chung article,

Walmsley [Ian Walmsley, professor of experimental physics at the University of Oxford] said it’s easier to maintain coherence in smaller objects because they can be isolated practically from disturbances. Things are trickier in larger systems that contain lots of interacting, moving parts.

Two things helped the researchers get around this in their experiment, Sussman [Ben Sussman, a quantum physicist at the National Research Council of Canada and adjunct professor at the University of Ottawa] said:

  • The hardness of the diamonds meant it was more resistant to disturbances that could destroy the coherence.
  • The extreme speed of the experiment — the researchers used laser pulses just 60 femtoseconds long, about 6/100,000ths of a nanosecond (a nanosecond is a billionth of a second) — meant there was no time for disturbances to destroy the quantum effects.

Laser pulses were used to put the two diamonds into a state where they were entangled with one another through a shared vibration known as a phonon. By measuring particles of light called photons subsequently scattered from the diamonds, the researchers confirmed that the states of the two diamonds were linked with each other — evidence that they were entangled.

If you are interested in the team’s research and can get past Science magazine’s paywall, here’s the citation,

“Entangling Macroscopic Diamonds at Room Temperature,” by K.C. Lee; M.R. Sprague; J. Nunn; N.K. Langford; X.-M. Jin; T. Champion; P. Michelberger; K.F. Reim; D. England; D. Jaksch; I.A. Walmsley at University of Oxford in Oxford, UK; B.J. Sussman at National Research Council of Canada in Ottawa, ON, Canada; X.-M. Jin; D. Jaksch at National University of Singapore in Singapore. Science 2 December 2011: Vol. 334 no. 6060 pp. 1253-1256 DOI: 10.1126/science.1211914

All of the media reports I’ve seen to date focus on the UK and Canadian researchers and I cannot find anything about the contribution of the researcher based in Singapore.

I do wish I could read more languages as I’d be more likely to find information about work which is not necessarily going to be covered in English language media.

Dancing the Higgs boson?

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Sometimes known as the ‘god’ particle, there’s talk that a major announcement is about to be made about the Higgs boson next week at CERN (European Laboratory for Particle Physics). From the Dec. 6, 2011 posting by Ian Sample on the Guardian science blogs,

Soon after Rolf-Dieter Heuer, the director general at Cern, emailed staff about next Tuesday’s seminar [Dec. 13, 2011] on the most sought-after particle in modern times, rumours hit the physics blogs that the lab might finally have caught sight of the Higgs boson.

I wrote last week that the heads of the two groups that work on the Atlas and CMS detectors at the Large Hadron Collider (LHC) will give the talks. That in itself is telling – usually more junior researchers present updates on the search for the missing particle. [emphasis mine]

Sample provides an explanation of the Higgs boson and why it and its mechanism has such importance,

…  The Higgs mechanism describes an invisible field that, it is argued, split one force into two soon after the birth of the universe. Specifically, it divided an ancient “electroweak” force into the electromagnetic and weak forces we see at work today. The latter is seen in some radioactive decay processes, and is involved in creating sunshine. [emphasis mine]

This is an excerpt from the full explanation, which precedes answers from a number of physicists around the world to a question Sample asked about what gives mass to fundamental particles. Here are a few randomly chosen answers Sample received to his question,

Shelly Glashow, Boston University. Nobel prize in physics, 1979

“They said when the collider goes on
Soon they’d see that elusive boson
Very soon we shall hear
Whether Cern finds it this year
But it’s something I won’t bet very much on.”

Frank Wilczek, MIT. Nobel prize in physics, 2004

“The Higgs mechanism for generating masses is extremely attractive and has no real competition. Beyond that there’s little certainty. A near-minimal implementation of supersymmetry, perhaps augmented with ultra-weakly interacting particles, is the prettiest possibility. So I’d like several Higgs particles, Higgisinos, some ghostly stuff, and a pony.”
[Note: A Higgsino is a supersymmetric partner of a Higgs boson].

…

Martinus Veltman, Universities of Michigan and Utrecht. Nobel prize in physics, 1999

“You are mistaken about the Higgs search at Cern. The machine runs at half energy so far, and no one expects relevant (for the Higgs particle) results. After the shutdown [in 2013] the machine will gradually go up in energy, and if all goes well (this is non-trivial) then in about half a year the machine energy might reach design value and there might be Higgs-relevant results. So if you are thinking next week then you are mistaken. Of course, we never know what surprises nature has in store for us … It is my opinion that there is no Higgs.”

Philip Anderson, Princeton University. Nobel prize in physics, 1977

“I doubt if the opinions of one who thinks about these problems perhaps every 30 years or so will carry much weight. I’ve been busy. But the last time I thought, I realised a) that the Higgs (-A) mechanism fits the facts too beautifully not to be true, but b) it must be incomplete, because there’s no proper accounting of the vacuum energy.”
[Note: Anderson essentially described the Higgs mechanism in 1962, two years before Higgs and five other physicists published the theory.]

There are more answers in Sample’s posting.

While it’s fascinating to see how widely divergent opinions are about Higgs, I have to confess my understanding of all this is rudimentary. Perhaps the dancers and performers (my Nov. 28, 2011 posting about a dance/performance residency at CERN) will help clarify the matter for me.

Fundamentals of nanoelectronics at nanoHUB-U

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nanoHUB is a project hosted by Purdue University’s (Indiana, US) Network for Computational Nanotechnology. A successful online community has been created over a number of years. My Nov. 16, 2010 posting noted that they had over 150,000 users at that time. Their latest (Dec. 2, 2011) newsletter notes a new initiative, nanoHUB-U,

We are launching a series of online short courses on nanoscience and nanotechnology that will be offered over the next couple of years. This initiative builds on the open content we have on nanoHUB.org. We think the approach is unique – the courses are designed to be broadly accessible without many prerequisites, and the material is presented in an original way. Students get access to a completely new set of lectures not available on nanoHUB, extensive lecture notes, exams, homeworks, Q & A forums, and exercises using nanoHUB tools.

We’re starting with Prof. Supriyo Datta’s Fundamentals of Nanoelectronics on January 23, 2012.

Here’s a little more information about the course from the registration page,

Fundamentals of Nanoelectronics Part I: Basic will be the first offering of two, five-week online courses. This offering is based on unique courses developed at Purdue, whose videotaped lectures posted on the nanoHUB have attracted 75,000+ viewers since 2004, with enthusiastic reviews. Part I is accessible to anyone familiar with calculus and elementary differential equations.

Here’s a little information about the instructor,

Supriyo Datta is the Thomas Duncan Distinguished Professor at the School of Electrical and Computer Engineering, Purdue University. He is a Fellow of the IEEE (Institute for Electrical and Electronics Engineers) and the APS (American Physical Society) and his books

  1. Electronic Transport in Mesoscopic Systems, Cambridge (1995)
  2. Quantum Transport: Atom to Transistor, Cambridge (2005)

are standard in the field. This course is based on his soon to be published book

* Lessons from Nanoelectronics: A New Perspective on Transport, World Scientific (2012)

which seeks to convey the key concepts to non-specialists.

He has received IEEE Technical Field Awards both for research and for graduate teaching and was recently awarded the Procter Prize for “outstanding contribution to scientific research and demonstrated ability to communicate the significance of this research to scientists in other disciplines.”

This course is $30US.

DARPA’s Shredder challenge solved

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Out of a field of almost 9,000 registered teams, the San Francisco-based “All Your Shreds Are Belong to U.S.” team won the $50,000 prize. Here’s a brief description of the challenge (highlighted in my Nov. 28, 2011 posting), from the DARPA Shredder Challenge page,

Today’s troops often confiscate the remnants of destroyed documents in war zones, but reconstructing them is a daunting task. DARPA’s [Defense Advanced Research Projects Agency] Shredder Challenge called upon computer scientists, puzzle enthusiasts and anyone else who likes solving complex problems to compete for up to $50,000 by piecing together a series of shredded documents.

The goal was to identify and assess potential capabilities that could be used by our warfighters operating in war zones, but might also create vulnerabilities to sensitive information that is protected through our own shredding practices throughout the U.S. national security community.

There were five puzzles in all and, as of my Nov. 28, 2011 posting, the fifth was the only one that had not been solved. By Dec. 2, 2011 all the puzzles had been solved. From the Dec. 5, 2011 news item on physorg.com,

The ‘All Your Shreds Are Belong to U.S.’ team, which won the $50,000 prize, used custom-coded, computer-vision algorithms to suggest fragment pairings to human assemblers for verification. In total, the winning team spent nearly 600 man-hours developing algorithms and piecing together documents that were shredded into more than 10,000 pieces.

…

The Shredder Challenge represents a preliminary investigation into the area of information security to identify and assess potential capabilities that could be used by war fighters operating in war zones to more quickly obtain valuable information from confiscated, shredded documents and gain a quantitative understanding of potential vulnerabilities inherent to the shredding of sensitive U.S. National security documents.

While the contest is now closed, it’s still possible to try this puzzle for fun. You can find out more about the various puzzle solutions and the winning team’s submission here.

India’s military considers nanotechnology

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In the interest of some balance I’m highlighting a nanotechnology workshop that was held for the Indian military. (It turns out the US military isn’t the only military force interested in nanotechnology.) From the Nov. 30, 2011 news item on Nanowerk,

A two-day National Workshop on Nanotechnology for Defence Applications (NWNDA-2011) concluded today in New Delhi. The event marked the Golden Jubilee of Solid State Physics Laboratory (SSPL), a premier institute of the Defence Research & Development Board (DRDO), working on development of solid state devices for defence needs.

A sustained and dedicated research over the past few years has led DRDO to development of products that are currently at different stages of maturity. To realize deliverable products, product engineering and technologies for up-scaling are essential components in the product development process, a collaborative and coherent approach is being worked out. This workshop is an important and crucial platform for realization of this objective.

The workshop was inaugurated by Dr. T. Ramasami, Secretary, Department of Science & Technology, who appreciated the work being carried out by DRDO in the field of Nanotechnology, particularly in the field of sensors and composites.

More details at Nanowerk.

Ray Bradbury jumps on the e-book train after dissing the Internet, television, and all that other newfangled stuff

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Most of the recent headlines about Ray Bradbury’s book, Farenheit 451, being made available as an e-book hint or highlight the fact that Bradbury is a longstanding opponent to anything which challenges the primacy of the printed word. From the Nov. 30, 2011 BBC news item, Fahrenheit 451 becomes e-book despite author’s feelings,

As late as last year, Mr Bradbury remained firmly opposed to the idea of his book appearing as a digital title.

“I was approached three times during the last year by internet companies wanting to put my books on an electronic reading device,” he told the Los Angeles Times in 2010.

“I said to Yahoo: ‘Prick up your ears and go to hell.'”

He also complained about the spread of modern technology.

“We have too many cellphones. We’ve got too many internets. We have got to get rid of those machines. We have too many machines now,” he said.

However, Mr Bradbury’s agent said the deal had become unavoidable.

“We explained the situation to him that a new contract wouldn’t be possible without e-book rights,” Michael Congdon said.

“He understood and gave us the right to go ahead.”

Mike Masnick in his Nov. 29, 2011 posting on Techdirt notes this about the deal,

Of course, if Bradbury is worried that people are going to leave behind his precious paper (more on that in a minute), perhaps his publishers are saving him… by pricing the ebook at a ridiculous $9.99. This is for a book that you can buy in a paper copy used for a penny and new for $2.84. And the publisher thinks $9.99 for a version that doesn’t require materials, packaging or shipping should be many times the cost?

Masnick goes on to note that Farenheit 451 was really a critique of the new media of the day, television.