Official Word on Superluminal Neutrinos Leaves Warp-Drive Fans a Shred of Hope—Barely

by Edwin Cartlidge on 24 February 2012, 11:31 AM

The CERN particle physics laboratory in Geneva has confirmed Wednesday's report that a loose fiber-optic cable may be behind measurements that seemed to show neutrinos outpacing the speed of light. But the lab also says another glitch could have caused the experiment to underestimate the particles' speed.

In a statement based on an earlier press release from the OPERA collaboration, CERN said two possible "effects" may have influenced the anomalous measurements. One of them, due to a possible faulty connection between the fiber-optic cable bringing the GPS signals to OPERA and the detector's master clock, would have caused the experiment to underestimate the neutrinos' flight time, as described in the original story. The other effect concerns an oscillator, part of OPERA's particle detector that gives its readings time stamps synchronized to GPS signals. Researchers think correcting for an error in this device would actually increase the anomaly in neutrino velocity, making the particles even speedier than the earlier measurements seemed to show.

CERN's statement says OPERA scientists are studying the "potential extent of these two effects" but doesn't indicate which source of error (if either) is likely to outweigh the other. However, Lucia Votano, director of the Gran Sasso laboratory, says the "main suspicion" focuses on the optical-fiber connection. She adds that OPERA researchers deserve credit for "having tenaciously followed this particular evidence via checks completed in the last few days."

The two effects will get a new round of tests in May, when the two labs are scheduled to make velocity measurements with short-pulsed beams designed to give readings much more precise than scientists have achieved so far.

Tiny Neutrinos May Have Broken Cosmic Speed Limit

Tiny Neutrinos May Have Broken Cosmic Speed Limit
By DENNIS OVERBYE
Published: September 22, 2011

Roll over, Einstein?

The physics world is abuzz with news that a group of European physicists plans to announce Friday that it has clocked a burst of subatomic particles known as neutrinos breaking the cosmic speed limit — the speed of light — that was set by Albert Einstein in 1905.


If true, it is a result that would change the world. But that “if” is enormous.


Even before the European physicists had presented their results — in a paper that appeared on the physics Web site arXiv.org on Thursday night and in a seminar at CERN, the European Center for Nuclear Research, on Friday — a chorus of physicists had risen up on blogs and elsewhere arguing that it was way too soon to give up on Einstein and that there was probably some experimental error. Incredible claims require incredible evidence.

“These guys have done their level best, but before throwing Einstein on the bonfire, you would like to see an independent experiment,” said John Ellis, a CERN theorist who has published work on the speeds of the ghostly particles known as neutrinos.

According to scientists familiar with the paper, the neutrinos raced from a particle accelerator at CERN outside Geneva, where they were created, to a cavern underneath Gran Sasso in Italy, a distance of about 450 miles, about 60 nanoseconds faster than it would take a light beam. That amounts to a speed greater than light by about 0.0025 percent (2.5 parts in a hundred thousand).

Even this small deviation would open up the possibility of time travel and play havoc with longstanding notions of cause and effect. Einstein himself — the author of modern physics, whose theory of relativity established the speed of light as the ultimate limit — said that if you could send a message faster than light, “You could send a telegram to the past.”

Alvaro de Rujula, a theorist at CERN, called the claim “flabbergasting.”

“If it is true, then we truly haven’t understood anything about anything,” he said, adding: “It looks too big to be true. The correct attitude is to ask oneself what went wrong.”

The group that is reporting the results is known as Opera, for Oscillation Project with Emulsion-Tracking Apparatus. Antonio Ereditato, the physicist at the University of Bern who leads the group, agreed with Dr. de Rujula and others who expressed shock. He told the BBC that Opera — after much internal discussion — had decided to put its results out there in order to get them scrutinized.

“My dream would be that another, independent experiment finds the same thing,” Dr. Ereditato told the BBC. “Then I would be relieved.”

Neutrinos are among the weirdest denizens of the weird quantum subatomic world. Once thought to be massless and to travel at the speed of light, they can sail through walls and planets like wind through a screen door. Moreover, they come in three varieties and can morph from one form to another as they travel along, an effect that the Opera experiment was designed to detect by comparing 10-microsecond pulses of protons on one end with pulses of neutrinos at the other. Dr. de Rujula pointed out, however, that it was impossible to identify which protons gave birth to which neutrino, leading to statistical uncertainties.

Dr. Ellis noted that a similar experiment was reported by a collaboration known as Minos in 2007 on neutrinos created at Fermilab in Illinois and beamed through the Earth to the Soudan Mine in Minnesota. That group found, although with less precision, that the neutrino speeds were consistent with the speed of light.

Measurements of neutrinos emitted from a supernova in the Large Magellanic Cloud in 1987, moreover, suggested that their speeds differed from light by less than one part in a billion.

John Learned, a neutrino astronomer at the University of Hawaii, said that if the results of the Opera researchers turned out to be true, it could be the first hint that neutrinos can take a shortcut through space, through extra dimensions. Joe Lykken of Fermilab said, “Special relativity only holds in flat space, so if there is a warped fifth dimension, it is possible that on other slices of it, the speed of light is different.”

But it is too soon for such mind-bending speculation. The Opera results will generate a rush of experiments aimed at confirming or repudiating it, according to Dr. Learned. “This is revolutionary and will require convincing replication,” he said.


This article has been revised to reflect the following correction:

Correction: September 22, 2011

A previous version of this article misspelled Alvaro de Rujula's last name.

A version of this article appeared in print on September 23, 2011, on page A8 of the New York edition with the headline: Tiny Neutrinos May Have Broken Cosmic Speed Limit.


Source: NYT Sciense

Graphene Links Could Enable Super-Fast Internet

Researchers in Manchester and Cambridge show graphene’s potential for superfast broadband


Graphene, the magic material that has the science world buzzing, has been shown to be a potential accelerator for a future high-speed Internet.
The substance is strong, flexible and impermeable, but its greatest properties lie in it being the thinnest material known with stunning conductivity. It is this final attribute that has attracted attention to graphene as a potential successor to silicon in electronic devices, but new research has shown photonic properties that were not realised before.


Nanostructures Make Light Work


A team of researchers at the universities of Manchester and Cambridge have been looking at ways to improve the absorption of light by graphene. In its natural state, the material only absorbs three percent of light falling on it. Despite this, it has been shown acting in a 10Gbps optical communication link.
In a paper published in Nature Communications, the researchers show that, by combining graphene with plasmonic nanostructures, acting as minutely thin wires, the efficiency of graphene-based photodetectors can be increased by up to 20 times. In addition, the wavelength and polarisation of absorbed light can be altered by using nanostructures of different geometries.
“Such graphene devices can be incredibly fast, tens and potentially hundreds of times faster than communication rates in the fastest Internet cables. This is due to the unique nature of electrons in graphene, their high mobility and velocity,” the researchers claim.
Nobel Prize winners Andre Geim and Konstantin Novoselov are part of the team and were the discoverers of graphene in 2004. Since then, IBM has demonstrated how the material can be used for minute chips in wireless devices, the University of California has created a miniature, incredibly fast optical data transmitter using graphene as a modulator to switch a light source on and off, and Samsung has demonstrated a 25-inch touch screen coated in the material.
The story of graphene seems to extend monthly and Novoselov, who works with the Manchester University team, said, “The technology of graphene production matures day by day, which has an immediate impact both on the type of exciting physics which we find in this material, and on the feasibility and the range of possible applications.”


Source: e-Week Europe