The National Institute of Standards and Technology (NIST) has demonstrated error-free quantum communication by pairs of entangled atoms, promising secure quantum computers. Entanglement is a quantum phenomenon in which two particles take on identical internal states in close proximity. If conditions are right, the synchronization persists even after the particles become separated, enabling the quantum information processed by one member of the pair to be simultaneously processed by the other. Now NIST has demonstrated a method that lets entangled atoms communicate information nondestructively, potentially enabling long quantum calculations in which intermediate results could be obtained without disturbing their quantum states. The algorithm traps charged ions in four electromagnetic traps spaced only a few microns apart on the surface of a chip. Ultraviolet lasers then entangle two pairs of ions.
Monday, October 30, 2006
As recently as this summer, invisibility cloaks were only a theoretical possibility. Now the world's first cloaking demonstration has bent microwaves around a 7.2-cubic-inch enclosure, effectively hiding it from detection. The proof of concept suggests how engineers might pattern split-ring resonators to create "designer" metamaterials. Split-ring resonators--free-space rings of metal with a gap that prevents them from being a complete ring--are usually patterned on a fiberglass circuit board. When microwave radiation passes through them, they act as a dielectric whose magnetic permeability and electrical permittivity can be custom-tailored by adjusting the size and shape of the resonator. The cloak demonstrated earlier this month was designed to bend microwaves. But the researchers claim that with more engineering effort, EEs could create invisibility cloaks for any type of electromagnetic radiation, even visible light.
Monday, October 23, 2006
If you look at the surface-mounted components on a typical printed-circuit board, the large ones are likely to be the capacitors. For reasons that were not previously verified, the smaller a capacitor gets, the less capacitance it exhibits, often necessitating the use of larger capacitors to achieve the desired capacitance. Now a materials science group at the University of California, Santa Barbara claims to have figured out why, and has concluded that using platinum or gold electrodes can allow a capacitor's depolarization layer's thickness to be reduced by a factor of four.
Supercomputer simulations running in the trillions of operations per second provide a virtual test tube for the nanoparticles to be used in a new generation of magnetic media for tomorrow's hard-disk drives. To prove that point, researchers at the Pittsburgh Supercomputing Center and Oak Ridge National Laboratory recently modeled a promising nanoparticle material exhibiting a hitherto hidden capability that the researchers say could enable densities of 1 terabit/square inch.
Quantum mechanics predicts that measurements motivate mass--that the act of observing can affect the observed. Now a former National Security Agency scientist turned physics professor has demonstrated that motion can be elicited and quelled by quantum-level observations. Indeed, observations alone changed not only the physical motion of a device but also the motion's thermal consequence, according to Cornell University in a report on the largest device in which quantum mechanical effects have been observed. The device was an aluminum-on-silicon nitride resonating bar measuring 8.7 microns long by 200 nanometers wide, contained 10 trillion atoms.
The last holdout against the microminiaturization of electronics--the quartz crystal--may be set to fall. Wielding oscillators based on microelectromechanical-system technology, two startups aim to break quartz crystals' monopoly on the mechanical time references used in virtually all electronic devices today. If the two are successful, larger competitors with established MEMS programs could be hot on their heels. But while the rivals envision a multibillion-dollar market for MEMS oscillators, the parts' price tag could confine them, at least at the outset, to niche markets.
Thursday, October 19, 2006
The National Institute of Standards and Technology (NIST) said it has demonstrated what it claims is the world's first entangled atoms that could be used to communicate information nondestructively. By creating multiple pairings of entangled atoms, NIST scientist Dietrich Leibfried was able to transmit quantum data and verify its reception from one pair without destroying the information in the other pair. Entanglement—referred to by Albert Einstein as "spooky action at a distance"—is a quantum phenomenon in which two particles—atoms or photons in close proximity—take on identical internal states. The synchronization, if conditions are right, can persist even if the particles are separated so that information processed by one pair is simultaneously processed by the other. Researchers believe the phenomenon could serve as the basis for enabling quantum computing capabilities
Posted by R. Colin Johnson at 6:14 AM
Monday, October 16, 2006
A secret communications channel hidden beneath the noise floor of existing Internet public fiber-optic networks could serve as a conduit for uncrackable data transmission, electrical engineers from Princeton University said last week. Even the presence of data in the stealth channel is hidden; it's impossible to know that anything is being transmitted. At the Optical Society of America's annual meeting in Rochester, N.Y., the EEs reported on their design for a physical-layer modification that hides a secure communications channel amid the clamor of public traffic. The technique could cheaply retrofit the existing Internet with a mechanism for secure transmission of confidential and sensitive data, the researchers said.
Remember how digital converters for audio started out at 8 bits, then went to 16 and 24 bits before resetting to 1 bit with oversampling? Engineers at Rice University will propose this week that we reset our megapixel cameras to 1 pixel and our video cameras to 1 voxel, both with oversampling. The 1-pixel camera takes tens of thousands of rapid-fire shots to capture the equivalent of 1 million pixels in an image. So instead of expensive megapixel sensors with separate detectors for red, green and blue, the Rice EEs' approach needs only a 1-pixel multispectral sensor, simplifying hardware resources while enabling images to be formed from spectra never before imaged. The enabling chip for the 1-pixel camera is not the detector used to sense an application-specific spectrum--that could use any technology. Instead, Texas Instruments Inc.'s digital micromirror array is used to project light from the lens onto the sensor. The micromirror array is the same chip that's used in Digital Light Processor televisions. Here, the lens focuses light onto the 1,024 x 768-pixel digital micromirror chip, which in turn projects all of its light into a single photodiode.
Monday, October 09, 2006
If you've seen any of the new IMAX 3-D movies, you surely noticed the jump in quality over the 3-D experience of yesteryear. Now a 3-D display maker has tapped an encoding technology that reproduces that cinematic experience on a 19-inch LCD for scientific visualization and medical diagnostics. The two LCDs are precision-aligned, then laminated on top of each other. The left and right images are separately displayed to the viewer's eyes, because the viewer wears passive glasses whose lenses are orthogonally polarized at 90° to each other.
Monday, October 02, 2006
A project to generate electricity from solar energy using a Stirling engine looks to create farms that will light and cool the households of millions of California customers, at a cost that by 2011 may rival what traditional sources are charging. The technology originated when Stirling Energy Systems Inc. agreed to supply Sandia National Laboratories with solar dishes in return for Sandia's addition of mechatronics to allow the dishes to track the sun. Together, Sandia (Albuquerque, N.M.) and Stirling Energy Systems (Phoenix) designed a 1-megawatt solar power substation capable of direct connections to the existing U.S. power grid. From 2007 to 2010, the Sandia program will perfect methods of ganging the substations into successively larger groups, operating at increasingly higher voltages. In California, the state government has mandated that utilities invest in renewable energy sources for at least 20 percent of their power by 2010.
"You don't need a weather man to know which way the wind blows," Bob Dylan sang in "Subterranean Homesick Blues." That sentiment rings especially true if your turbine is blowin' in the wind more than 100 miles offshore, because there the breeze is always stiff. Now a designer of offshore drilling rigs for oil companies at MIT has validated the blueprints for an extra-large, 5-megawatt floating wind turbine with the National Renewable Energy Laboratory. Wind farms began on land, as eyesores familiar to anyone who drives much (for instance, from Los Angeles to Palm Springs). But the lack of constant wind onshore and the steady stream of complaints from the public have prompted a migration offshore. The public continues to complain about wind farms when they are visible from shore, prompting the newer projects to move even farther out. Last month, a consortium including oil company Talisman Energy Inc. and Scottish and Southern Energy began testing a 5-MW wind turbine almost 10 miles off the coast of Moray Firth, Scotland, where at 150 feet it is shallow enough to utilize an underwater foundation. For the United States, the engineers propose abandoning traditional rigid attachments to the ocean bottom, freeing the floating wind turbines to be located on the high seas, where the wind blows hardest. The Scottish project, if successful, will be a farm of 200 turbines. The U.S. plan is to up the ante by designing a farm twice as big--400 turbines, to power about 100,000 homes--located 100 miles off the New England coast.
A new breed of ultrawideband radio that uses a mixer instead of a delay line could solve longstanding deployment problems, its developers say. The technique, invented by engineers at the University of Massachusetts (Amherst), was unveiled last week at the International Conference on Ultra-Wideband in Waltham, Mass. One of the most promising approaches to UWB was to send a nanosecond reference pulse before each data pulse, giving the radio a time frame in which to search its spectrum for data bits. However, after nearly a decade of attempting to use delay lines to synchronize data collection, most research into that approach has come to a halt. The new approach scraps the delay line idea for a mixer, which is easy to build even for ultrashort pulses. A reference pulse is still sent, but is mixed together with the data bit and multiplied by a cosine. On the receiving end is another mixer, with one input coming from the antenna and one from a sine wave generator.
Using a superconducting detector, the National Institute of Standards and Technology has set a new world's distance record in quantum-key distribution--an uncrackable encryption technology that ensures absolute security by harnessing the quantum-physics principle that observations affect outcome. Until last week, Toshiba Research Europe Ltd. and Cambridge Research Laboratory held the record for the most sensitive detector with a prototype system that stretched 75 miles. Now NIST has upped the ante by more than 50 percent, reporting last week that it had transmitted over nearly 115 miles.