Technology Trends

If you use a webcam to talk with your mom, this tool is not for you. But if you’re working for a company and that you have to routinely discuss about sensitive future projects or the possible acquisition of another company, you need more security, and this new video conferencing system based on quantum cryptography is a tool you need. According to this article from Nature, researchers from Toshiba have developed a system which can generate 100 quantum ‘keys’ every second, fast enough to protect every frame in a video exchange. This technology, which today is working over a distance of about 120 kilometers, could become commercially available within two years at an initial cost of $20,000. Read more…

Here is the introduction from Nature.

Scientists from Toshiba’s Cambridge Research Laboratory unveiled their invention to business leaders and government officials at Britain’s Department of Trade and Industry in London on 27 April.

Their system is capable of generating 100 quantum ‘keys’ every second. This is fast enough for every individual frame of video to be protected by its own encryption. “This makes the system highly secure,” says Andrew Shields, who leads the Cambridge team. “It would take an enormous computational resource to crack this frame by frame.”

Of course, today’s videoconferencing tools using conventional encryption are already pretty secure. But if the NSA wants to check your conversation, I bet it can. With quantum cryptography, this is a different story.

Quantum cryptography promises to stop such eavesdroppers. The system works by first establishing a ‘key’ that provides instructions on how to decode an incoming message. This key is built into the quantum state of photons. Intercepting a message breaks the key and alerts the sender and intended recipient to the security breach, because the very act of observing a quantum state changes it.

The Quantum Information Group at Toshiba gives more details on this subject on this page about Security from Eavesdropping. Below is a diagram illustrating the concept (Credit: Toshiba’s Cambridge Research Laboratory).

Using single photons to carry the bit material for the key prevents undetected eavesdropping. Because each bit is carried by a single photon, it is not possible for a hacker to tap in and remove part of the signal, as shown in the illustration. Single photons do not split, so if the hacker (Eve) measures the photons on the fibre, they will not reach the intended recipient (Bob). Only the photons that arrive at Bob are used to form the key, so Eve cannot gain any useful information by this crude ‘tapping’ attack.

The first commercial applications of quantum cryptography are now about one year old. However, this new system offers new levels of performances, according to Nature.

Unlike previous systems, which become unreliable when they heat up, this device can run continuously for more than four weeks, says Shields. The quantum information can only go so far before being corrupted by random interactions with surrounding material, however. “We’ve shown this can work over 120 kilometres of fibre,” says Shields.

Toshiba has already built a Quantum Cryptography Prototype. And the research work has been published by Applied Physics Letters (Vol. 84, Issue 19, Pages 3762-3864, May 10, 2004) under the title “Quantum key distribution over 122 km of standard telecom fiber.” Here is a link to the abstract.

We report a demonstration of quantum key distribution over a standard telecom fiber exceeding 100 km in length. Through careful optimization of the interferometer and single photon detector, we achieve a quantum bit error ratio of 8.9% for a 122 km link, allowing a secure shared key to be formed after error correction and privacy amplification. Key formation rates of up to 1.9 kbit/s are achieved depending upon fiber length. We discuss the factors limiting the maximum fiber length in quantum cryptography.

Finally, here is a link to the full paper (PDF format, 14 pages, 68 KB).

Sources: Mark Peplow, Nature, April 28, 2005; Toshiba’s Cambridge Research Laboratory website

Related stories can be found in the following categories.

• Cryptography
  
  
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In “Lobster colour has quantum cause,” Nature writes that Dutch researchers have found why lobsters change colors when they are cooked. According to Nature, “a lobster’s colour is due to a pigment molecule called astaxanthin, which is attached to a protein called crustacyanin.” The Dutch team, using nuclear magnetic resonance spectroscopy and computer simulations, showed that these astaxanthin molecules, grouped in pairs, are interfering with one another. As a result, it shifts their quantum energy states, altering the wavelength of light they can absorb, thus turning black when cooked. The article doesn’t say how many lobsters the researchers used — and ate — for their experiments, but read more…

First, Nature describes the problem — or the situation.

Chemists know that a lobster’s colour is due to a pigment molecule called astaxanthin, which is attached to a protein called crustacyanin. Astaxanthin is one of the carotenoid pigments responsible for the bright red colours of many animals and plants, including those of oranges, tomatoes and some birds’ feathers.

When a lobster is boiled, its crustacyanin proteins unwind in the heat and the astaxanthin pigment falls off. This ‘free’ astaxanthin is red, just like most other carotenoids, and gives the lobster its freshly-cooked colour. But chemists were mystified as to why live lobsters are blue-black.

Then, Nature describes the Dutch team’s experiments.

The team followed up on the discovery in 2002 that astaxanthin molecules in the crustacyanin proteins are grouped in pairs that cross each other in an X-shape.

This pairing, the researchers’ calculations show, means that the two molecules interfere with one another, like cross-talk between electrical signals in neighbouring wires, and this shifts their quantum energy states. That in turn alters the wavelength of light that they absorb, accounting for most of the blackness.

And here is the conclusion of Francesco Buda of Leiden University in the Netherlands, one of the researchers involved in the project.

“It’s surprising that it took such a long time to solve this problem,” says Buda. But he admits it is only in the past five to ten years that computers have been able to handle the demanding quantum-mechanical calculations involved.

The research work has been published by the Journal of the American Chemical Society under the title “Spectroscopy and Quantum Chemical Modeling Reveal a Predominant Contribution of Excitonic Interactions to the Bathochromic Shift in -Crustacyanin, the Blue Carotenoprotein in the Carapace of the Lobster Homarus gammarus.” Here is a link to the abstract.

And if you want to know more about lobsters, but in plain English, you can read this page at Wikipedia. Or you can check Lobster Facts, written by Alan M. Stewart. It features a picture of a two-color lobster named the Joker, introduced by these words: “The odd thing about this animal is that the cephalothorax is all one [natural] color while the rest of the animal is symmetrically different. Even its mouth parts were normal-colored on the right, and orange on the left.” Is this a real lobster or a PhotoShop joke? You’ll tell me.

Sources: Philip Ball, Nature, February 15, 2005; and various websites

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• Biotechnology
  
  
• Chemistry
  
  
• Nature
  
  
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It’s an antenna, it’s a nanomachine, and it’s a macroscopic quantum system. This antenna, made of 50 billion atoms, is so far the largest structure to display quantum mechanical movements. It’s also the fastest device of its kind in the world, oscillating about 1.5 billion times per second. Such technology might soon be used in our cell phones. But more importantly, this nanomechanical device bridges classic and quantum physics. Such ”mechanical/quantum mechanical hybrids could be used for quantum computing” in the future. Read more…

Here is the introduction from this Boston University news release.

A team of Boston University physicists led by Assistant Professor Pritiraj Mohanty developed the nanomechanical oscillator. Operating at gigahertz speeds, the technology could help further miniaturize wireless communication devices like cell phones, which exchange information at gigahertz frequencies. But, more important to the researchers, the oscillator lies at the cusp of classic physics, what people experience everyday, and quantum physics, the behavior of the molecular world.

Please note that this is the second appearance of Mohanty’s team in this space. I already mentioned their works back in October 2004 in “Nanomechanical Memory Outstrips Chip Technology.”

Now, let’s look at some — impressive — numbers.

Comprised of 50 billion atoms, the antenna built by Mohanty’s team is so far the largest structure to display quantum mechanical movements.

“It’s a truly macroscopic quantum system,” says Alexei Gaidarzhy, a graduate student in the BU College of Engineering’s Department of Aerospace and Mechanical Engineering. The device is also the fastest of its kind, oscillating at 1.49 gigahertz, or 1.49 billion times a second, breaking the previous record of 1.02 gigahertz achieved by a nanomachine produced by another group.

The above image shows different views of this nanomechanical structure. The center, (a), is a scanning electron micrograph of the suspended antenna oscillator. The nanomechanical antenna consists of a central silicon beam, 10.7 microns long and 400 nm wide, that bears a “paddle” array 500 nm long and 200 nm wide along each side. In (b), you can see a modal simulation of the antenna structure, showing the low frequency fundamental resonance mode. And in the high order collective mode (c), the paddles vibrate at their own natural frequency. (Credit: Pritiraj Mohanty, Boston University)

The research work has been published in a recent issue of Physical Review Letters on January 25, 2005 under the name “Evidence for Quantized Displacement in Macroscopic Nanomechanical Oscillators.” Here is a link to the abstract.

We report the observation of discrete displacement of nanomechanical oscillators with gigahertz-range resonance frequencies at millikelvin temperatures. The oscillators are nanomachined single-crystal structures of silicon, designed to provide two distinct sets of coupled elements with very low and very high frequencies. With this novel design, femtometer-level displacement of the frequency-determining element is amplified into collective motion of the entire micron-sized structure. The observed discrete response possibly results from energy quantization at the onset of the quantum regime in these macroscopic nanomechanical oscillators.

And here is a link to the full article (PDF format, 4 pages, 955 KB). The above illustration comes from this article.

Finally, for explanations written in — almost — plain English, you might read the news release quoted above.

Sources: Boston University, via EurekAlert!, February 9, 2005; and various websites

Related stories can be found in the following categories.

• Nanotechnology
  
  
• Physics
  
  
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• Science
  

Many teams of nanoscientists around the world want to be the first one to build quantum computers. To achieve this goal, they’re using artificial atoms — also known as ‘quantum dots.’ But even if they’re able to use them, not a single team has been able to consistently control their quantum mechanical states — or their properties — at the nanoscale. Now, a team from Ohio University claims it found a flaw in quantum dot construction and proposes a solution. And guess what? As it happens often in research, this new finding is based on a very simple fact: an interference between two physical phenomena. Read more…

[For example,] experimental scientists in Germany had blasted the quantum dots with light to create the quantum mechanical state needed to run a quantum computer. But they couldn’t consistently control that state, explained Sergio Ulloa, an Ohio University professor of physics and astronomy. Jose Villas-Boas, a postdoctoral fellow at Ohio University, Ulloa and Associate Professor Alexander Govorov developed theoretical models to learn what went wrong.

The problem, they argued, happens during the creation of the type of quantum dots under study. Using a molecular beam epitaxy chamber, scientists spray paint a surface with atoms under high temperatures, creating an atomic coating. As more layers are added, the quantum dots bead up on the surface like droplets of water, Ulloa said.

But a fine residue left behind on the surface that Ulloa calls the “wetting layer” can cause problems during experiments. When experimental scientists blasted the quantum dots with a beam of light in previous studies, the wetting layer caused interference, instead of allowing the light to enter the dot and trigger the quantum state, he explained.

The illustration above “shows a quantum dot (blue central bulge) bombarded from the top with laser light. The laser produces excitations (called excitons) inside the dot, and the electric fields generated by the top and bottom gold contacts pull the electrons (yellow) and holes (red) away. Other electrons/holes are undesirably produced instead on the wetting layer, causing interference. The semiconductor compounds used in these experiments are Gallium Arsenide (GaAs) and Indium Gallium Arsenide (InGaAs).” (Credit for image and legend: Jose Villas-Boas) Here is a link to a larger version.

The study suggests that scientists could tweak the process by re-focusing the beam of light or changing the duration of the light pulses to negate the effects of the wetting layer, Villas-Boas said. One experimental physicist already has used the theoretical finding to successfully manipulate a quantum dot in the lab, he added. “Now that they know the problem, they realize there are a few ways to avoid it,” Villas-Boas said.

The research work from these scientists at the Ohio University’s Nanoscale & Quantum Phenomena Institute has been published in a recent issue of Physical Review Letters on February 8, 2005 under the name “Decoherence of Rabi Oscillations in a Single Quantum Dot.” Here is a link to the abstract.

We develop a realistic model of Rabi oscillations in a quantum-dot photodiode. Based in a multiexciton density matrix formulation we show that for short pulses the two-level model fails and higher levels should be taken into account. This affects some of the experimental conclusions, such as the inferred efficiency of the state rotation (population inversion) and the deduced value of the dipole interaction. We also show that the damping observed cannot be explained using constant rates with fixed pulse duration. We demonstrate that the damping observed is in fact induced by an off-resonant excitation to or from the continuum of wetting layer states. Our model describes the nonlinear decoherence behavior observed in recent experiments.

And if you want to know more, but don’t want to buy the article, here is a link to the full article (PDF format, 5 pages, 221 KB), thanks to the invaluable arXiv.org website.

Finally, just in case you wouldn’t know anything about Rabi oscillations, please read Isidor Isaac Rabi’s biography. He won the Nobel Prize for Physics in 1944.

Sources: Andrea Gibson, Ohio University, via EurekAlert!, February 10, 2005; and various websites

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• Materials
  
  
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In this must-read article, MIS, from Australia, asserts than in 10 to 15 years, we’ll be unable to use today’s technologies to build electronic devices always smaller and more powerful. Instead, three disruptive technologies will converge and deeply change our lives: nanotechnology, sensors and wireless technology. The author explains how this will influence molecular computing or quantum information processing. She also describes future advances in robotics, including nanobots. And the transportation industry will welcome the arrival of skycars, which are under development today. But will we travel anymore when holographic videoconferencing tools will be available? Please take a moment to check this fascinating article or read more below…

If nanobots and skycars sound more like sci-fi than a sane view of the future, then you may need to reprogram your mindset. Helene Zampetakis reports on the technology that will shape our lives in the decades to come.

A trio of disruptive technologies will converge over the next five to 15 years to overtake our incumbent systems and create new competencies that will profoundly change the way we organise our lives and the way we do business.

The driving principles behind modern technology are running out of steam: it is becoming prohibitively costly to continue to shrink technology, while Moore’s Law, which postulates the doubling of computer power every 18 months, is reaching its physical limits under current processes.

Luckily, help is coming with the convergence of three technologies.

But research that is underway today is expected to usher in a new technological era. Dubbed ‘embedded connectivity’ by Bob Hayward, vice-president and research fellow at Gartner, it will draw strength from nanotechnology, sensors and wireless technology.

The embedded world of the future will harness the power of billions of microprocessors on a single device, wirelessly connected to others, that can read the environment and react accordingly. Scientists portray a future in which we attach these devices to our bodies to communicate, set them loose on our streets to do menial tasks, and embed them in the commonplace objects of our lives to address our daily requirements.

The underlying foundation for this new era of embedded connectivity is nanotechnology, which is based on the manipulation of molecules less than 100 nanometres in size. “Nanotechnology means that rather than taking a chunk of silicon and carving it down to size, we build from the bottom up by assembling single molecules and atoms,” says Dr Terry Turney, director of CSIRO’s nanotechnology centre.

Zampetakis then looks at electronic circuitry and how it will be transformed by molecular self-assembly technology. She also describes future quantum information processing and wireless networks of sensors.

Now, let’s look at what she says about robotics.

It will be at least 20 years before we see microscopic ‘nanobots’, the much-hyped molecular manufacturing systems that have generated sci-fi like fears of mutating swarms running amok. But miniature robots are in fact under serious investigation.

In 2000, for example, MIT’s Bioinstrumentation Laboratory unveiled the Nanowalker, a sugar-cube sized prototype of the first autonomous nanorobot. The Nanowalker is able to move with great precision at a speed of about 4,000 steps a second and communicate wirelessly to a central computer.

Nanorobots will eventually construct materials atom by atom to create products that do anything from surveillance to in vitro navigation.

Larger robots will also be present and will become more independent.

Currently robots operate in controlled environments designed around them, such as car assembly plants, but the next generation of machines will be designed to function in a less structured world and to cope with unexpected changes to their environment.

Robotics research today centres around embedding these devices with fuzzy logic skills using sensors that will allow them to perceive and respond. Dr Peter Corke, autonomous systems team leader at CSIRO, says we could expect to see this class of machine delivering mail or medication or stacking store shelves at low cost to replace human labour in five to 10 years from now. Larger versions could be used down mines; and indeed this research is principally funded by the mining industry, along with organisations interested in flying robots that can inspect assets such as power lines.

And after decades of science-fiction stories, skycars will finally be there.

These will let us travel “when and where but especially how we wish”, according to Mark Moore, personal air vehicle sector manager for NASA’s Vehicle Systems Program.

NASA’s area of focus is a skycar (or personal air vehicle — PAV) designed not for getting about the city, but for travelling at high speeds for distances of between 160kms to 800kms. That would allow people to live in regional areas and commute into urban airfields for work.

Over the next decade Moore expects to see flying cars priced at less than US$100,000 using automated functionality based on NASA’s EquiPT (Easy-to-use, quiet Personal Transportation) technology set.

Moore says an obstacle to PAVs has been the intensity of training required to fly them, so automation is critical. The goal is to have the vehicle controlled by a computerised brain that senses and responds to weather conditions or other crafts in the vicinity, and compensates for technical failures.

And did you know you could order a skycar today? Moller International, based in California, is developing the M400 Skycar and hopes it will be certified by 2006. And you can purchase a 4-passenger Skycar today for a cool $995,000!

But will we travel with the arrival of the next generation of videoconferencing tools?

The synergy of vastly increased bandwidth, three-dimensional video projection and interactive holography systems is expected to change the way we collectively communicate, according to James Anderson, country manager of Polycom.

Videophones as a standard business tool are a decade away but it will be more like 20 years before research from bodies such as MIT’s Spatial Imaging Group or 3D visualisation company, Actuality Systems, yields practicable holographic videoconferencing. By then, however, “we’ll be looking at life-size holograms in 3D that can move around the room in full motion”, says Anderson.

Finally, Zampetakis looks at changes in information technology likely to happen in the next five to ten years.

Now, I have a question for you. Is this message from the future a one you like? Personally, I do.

Source: Helene Zampetakis, Managing Information Strategies, Australia, December 17, 2004; Moller International

Related stories can be found in the following categories.

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