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How Many Photons Can Dance On The Head Of A Chip?


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How Many Photons Can Dance on the Head of a Chip?

Quantum Physics doesn't get much weirder than this: When two subatomic particles enjoy a brief encounter, their fates stay coupled. Whatever happens to one is instantly mirrored by its mate--even if at opposite ends of the galaxy. Physicists call this phenomenon "entanglement." Although Albert Einstein could never accept it as real, numerous experiments have confirmed it. Now some scientists believe entanglement might be the answer to chipmakers' prayers.

A transatlantic team led by Jonathan P. Dowling, a senior researcher at NASA's Jet Propulsion Laboratory, figures entanglement can help pack chips with ever-smaller circuit lines, way beyond the infinitesimal 0.1-micron width that may be the brick wall for today's technology. That limit should be reached shortly after 2005.

The lines on advanced chips now are printed with ultraviolet light that has a wavelength of 248 nanometers. Normally, light can't reliably produce lines thinner than half its wavelength--in this case 0.124 microns--because the photons scatter in the air. But pump the light through a crystal that pairs up the photons, Dowling predicts, and the same equipment could write 0.06-micron lines. That's because the photons virtually "talk to each other and conspire to arrive at almost the same spot" on the silicon, he says. Since entanglement can link up multiple photons, it may be possible to write even finer lines. A trio, for instance, could print 0.04-micron lines. Dowling's crew is gearing up to test their theory in real-life experiments.By Otis Port; Edited by Ellen LickingReturn to top

Fish and Chips for Safer Turbines

Every year, tens of millions of young salmon navigate the Pacific Northwest's Columbia watershed on their way to the ocean. And every year nearly a million die, falling victim to the sharp blades of the turbines of hydroelectric dams. In an effort to stay the carnage, a group of researchers at the Pacific Northwest National Laboratory have designed electronics-packed, rubber-coated "sensor fish" to measure the conditions real fish encounter on their perilous journey to the sea. The objective: Use the information to design more fish-friendly turbines.

As the 6-inch sensor fish make their 15-second journey through the turbines, their sensors gather and store 96 kilobits of data on parameters such as changes in water pressure and shear forces. Little orange water wings attached to the fish inflate and bring them to the surface at the end of their swirling trip, while radio transmitters signal their location to the researchers. To download the data, researchers plug wires from the tails of the fish into a computer.

Thomas Carlson, the project's leader, says the research is already paying off. The sensor fish studies indicate that young fish tend to get trapped in the gaps of a turbine's blades. When those turbines are redesigned to minimize the gaps, juvenile injury rates are cut by 50%, and survival rates increase about 6%. Even better, Carlson's studies show that redesigning the turbines increases power output by about 4%. "Its a double win," says Carlson.Edited by Ellen LickingReturn to top

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Moonbots That Run on Sunlight

How much would 22 pounds of moon rocks fetch at an eBay auction? Not enough to pay for the $100 million cost of sending two foot-long robots to the moon to collect them. But Applied Space Resources Inc. (ASR), a Hicksville (N.Y.) startup, figures the real money will come from other sources, including broadcast rights to video footage of the robots scurrying over the moon.

ASR President Denise Norris is negotiating with Mark W. Tilden, a robotics maverick at Los Alamos National Laboratory, to send a pair of his mechanical critters. Tilden creates robots that depart from the norm. To avoid the need for elaborate software--and its potential bugs--he builds 'bots that act on a survival instinct. His solar-powered moon robots, he says, "will be driven to crawl toward the sun as it moves across the sky, incidentally picking up rocks along the way." Fittingly, the two that will make the journey will be the winners of a survival-of-the-fittest showdown in the New Mexico desert in 2003.By Otis Port; Edited by Ellen LickingReturn to top


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