German physicists are reporting they have broken the speed of light through quantum optics, but at least one expert in the field is disputing their claim. According to Albert Einstein's special theory of relativity, nothing can exceed the speed of light, or 186,000 miles per second. He theorized that the closer we come to traveling at the speed of light, the more time would appear to slow down, a phenomenon he called time dilation. Time dilation would, in theory, allow time travel. Günter Nimtz and Alfons Stahlhofen of the University of Koblenz, Germany, using a quantum optics phenomenon called photon tunneling, said they have instantly tunneled photons across a supposedly uncrossable barrier, and concluded that the photons must be crossing the barrier at a speed faster than that of light. They tunneled the photons across barriers of various distances, up to a maximum of three feet. Their work is reported in the Aug. 18 edition of New Scientist magazine. Nimtz and Stahlhofen reported they sandwiched two glass prisms together to make a 40-cm cube. They then used microwaves with a wavelength of 33 cm, which they said was long enough for large tunneling distances but still short enough that the prism could bend the photons' path. The microwaves shone straight through the cube. When the prisms were separated, the first prism reflected the microwaves and, as predicted by theory, a few photons tunneled across the gap between the prisms, continuing as if they were still together. Nimtz and Stahlhofen said the reflected photons and the tunneled photons both arrived at their respective photodetectors at the same time, leading them to conclude that some of the microwaves traveled faster than the speed of light. They also found that the tunneling time didn't change on a distance of up to three feet. "For the time being," Nimtz told New Scientist, "This is the only violation (of special relativity) that I know of. "In my opinion, tunneling is the most important physical process, because we have it in radioactivity and we have it in nuclear fusion," Nimtz told the magazine. "The temperature of the sun is not high enough to organize regular fusion of protons into helium (without tunneling). Some people are saying that the big bang happened because of tunneling. Recently, many people have argued that processes in biology and in our brain are based on tunneling." Back in 1995, Nimtz, then at the University of Cologne, claimed to have transmitted a microwave beam encoded with Mozart's "40th Symphony" at a speed 4.7 times faster than light, according to information on the Science News Web site. The photon tunneling conclusion reached by the physicists is drawing skepticism on numerous fronts, from online journalists, bloggers and quantum optics experts. Aephraim Steinberg, physics professor at the University of Toronto, is quoted in the same article as saying relativity hasn't been violated, and that Nimtz and Stahlhofen are just choosing to interpret the results that way. "The claim is worse than weak; it is silly," writes Chris Lee in a news story about the research on the Web site Ars Technica, "The paper in question has no data at all, so although it asserts that it has measured superluminal velocities, it offers nothing to back that up. It also has very little in the way of experimental detail, so we can't determine with certainty what they are measuring, making it very difficult to evaluate their claims."Comments posted on blog sites include dismissing the research as pure science fiction, skepticism that the physicists photodetectors were sensitive enough to accurately time the photons' arrivals, and eagerly anticipating time travel.For more information, visit: www.newscientist.com