Neutrinos may be too stubborn to go faster than light, but scientists at the National Institute of Standards and Technology (NIST) have figured out a way to get light itself to break Einstein's ultimate speed limit for the Universe.
Kind of.
Publishing last week in Physical Review Letters, NIST researchers Ryan Glasser, Ulrich Vogl, and Paul Lett said they've succeeded in producing "superluminal" light pulses, meaning that they've been able to get a portion of a short burst of light to arrive at its destination faster than it ought to get there if it was traveling at the speed of light.
As Phys.org explained, the team's four-wave mixing technique "reshapes" parts of those light pulses and "advances them ahead of where they would have been had they been left to travel unaltered through a vacuum."
The technique works because of the way light travels in bursts, "as a sort of (usually) symmetric curve like a bell curve in statistics," according to the science journal. Nothing can make the leading edge of the curve go any faster than the speed of light, but it's possible to "re-phase" or skew the "main hump" of the pulse backwards and forwards, meaning it can be made to arrive nanoseconds faster than it would without interference.
It's a "loophole" or trick of sorts to get around Einstein's universal speed limit, which still holds up despite the NIST team's accomplishment, Phys.org noted. But that trick may someday be used to "improve the timing of communications signals and to investigate the propagation of quantum correlations," according to the researchers.
Earlier this year, scientists debunked a claim by a team of European scientists who said they had observed sub-atomic particles traveling faster than light during a series of experiments that involved firing neutrinos from the CERN particle accelerator in Switzerland at detectors at the OPERA facility in Gran Sasso, Italy about 450 miles away.
Last September, OPERA scientists published results that stated they had measured the neutrinos arriving at their destination 60 nanoseconds faster than the "Universe's speed limit," 186,282 miles per second, should allow.
Those results understandably sent the scientific world into a tizzy. The published findings directly challenged the notion, established more than a century earlier by Albert Einstein in his special theory of relativity that the speed at which light travels is the absolute upper speed limit in the physical universe.
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