April 4th, 2006 by 
Abbas Halai
From Science:
Here’s the long and short of it: A lens that electronically switches its focus from far to near may someday provide an alternative to traditional bifocal lenses.
The natural lens in your eye is supposed to bend light rays and focus them on the retina at the back of the eye. If the eye is misshapen or not strong enough to do the job itself, glasses help bend the light rays through a process called refraction–the same one that makes a stick appear to kink when one end is submerged in water. Just how much a given lens bends light depends on its precise shape and curvature. Bifocals are essentially two lenses ground into a single piece of glass or plastic. In contrast, the new electronic lens is flat and focuses light through a phenomenon known as diffraction, in which light waves overlap either peak-to-trough to cancel one another out, or peak-to-peak to reinforce one another.
More here.
via 3QD
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April 4th, 2006 by Abbas Halai
With a brilliant idea and equations based on Einstein’s relativity theories, Ronald Mallett from the University of Connecticut has devised an experiment to observe a time traveling neutron in a circulating light beam. While his team still needs funding for the project, Mallett calculates that the possibility of time travel using this method could be verified within a decade.
“Einstein showed that mass and energy are the same thing,” said Mallett, who published his first research on time travel in 2000 in Physics Letters. “The time machine we’ve designed uses light in the form of circulating lasers to warp or loop time instead of using massive objects.”
To determine if time loops exist, Mallett is designing a desktop-sized device that will test his time-warping theory. By arranging mirrors, Mallett can make a circulating light beam which should warp surrounding space. Because some subatomic particles have extremely short lifetimes, Mallett hopes that he will observe these particles to exist for a longer time than expected when placed in the vicinity of the circulating light beam. A longer lifetime means that the particles must have flowed through a time loop into the future.
“Say you have a cup of coffee and a spoon,” Mallett explained to PhysOrg.com. “The coffee is empty space, and the spoon is the circulating light beam. When you stir the coffee with the spoon, the coffee – or the empty space – gets twisted. Suppose you drop a sugar cube in the coffee. If empty space were twisting, you’d be able to detect it by observing a subatomic particle moving around in the space.”
And according to Einstein, whenever you do something to space, you also affect time. Twisting space causes time to be twisted, meaning you could theoretically walk through time as you walk through space.
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