FBI investigates virtual casinos in Second Life

FBI investigators have visited Second Life's internet casinos at the invitation of the virtual world's creator Linden Lab, but the US government has not yet decided on the legality of virtual gambling.

FBI investigates virtual casinos in Second Life

Superconductors inspire quantum test for dark energy

Dark energy is so befuddling that it's causing some physicists to do their science backwards.

"Usually you propose your theory and then work out an experiment to test it," says Christian Beck of Queen Mary, University of London. A few years ago, however, he and his colleague Michael Mackey of McGill University in Montreal, Canada, proposed a table-top experiment to detect the elusive form of energy, without quite knowing why it might work. Now the pair have come up with the theory behind the experiment. "It is certainly an upside-down way of doing things," Beck admits.

Dark energy is the mysterious force that many physicists think is causing the expansion of the universe to accelerate. In 2004, Beck and Mackey claimed that the quantum fluctuations of empty space could be the source of dark energy and suggested a test for this idea. This involved measuring the varying current induced by quantum fluctuations in a device called a Josephson junction – a very thin insulator sandwiched between two superconducting layers.

Beck reasoned that if quantum fluctuations and dark energy are related, the current in the Josephson junction would die off beyond a certain frequency (see A table-top test for dark energy?). But they hadn't worked out what exactly caused the cut-off.

Now the duo say they know, and last week Beck presented the theory at a conference on unsolved problems for the standard model of cosmology held at Imperial College London.

Frequency cut-off

Quantum mechanics says that the vacuum of space is seething with virtual photons that are popping in and out of existence. Beck and Mackey suggest that when these virtual photons have a frequency below a certain threshold, they are able to interact gravitationally, contributing to dark energy.

Their theory is inspired by superconducting materials. "Below a critical temperature, electrons in the material act in a fundamentally different way, and it starts superconducting," says Beck. "So why shouldn't virtual photons also change character below a certain frequency?"

If so, virtual photons should behave differently below a frequency of around 2 terahertz, causing any currents in the Josephson junction to taper off above this frequency. Physicist Paul Warburton at University College London is building such a dark energy detector and could have results next year.

Some evidence that dark energy works like this may already have been found. In 2006, Martin Tajmar at the Austrian Research Centers facility in Seibersdorf and his colleagues noticed bizarre behaviour in a spinning niobium ring. At room temperature, niobium does not superconduct, and accelerometers around the ring measured that it was spinning at a constant rate. But once the temperature fell, the niobium started to superconduct, and the accelerometers suddenly picked up a signal (Gravity's secret).

Odd acceleration

"We measured an acceleration even though the ring's motion hadn't changed at all," says Clovis de Matos, who works at the European Space Agency in Paris and established the theory behind the experiment. He thinks the results could be explained if gravity got a boost inside the superconductor. "Beck and Mackey's gravitationally activated photon would have that effect," he says.

The controversial experiment seemed to fall foul of Einstein's equivalence principle, which states that all objects should accelerate under gravity at the same rate. It implied that "if you have two elevators, one made of normal matter and one made of superconducting matter, and accelerate them by the same amount, objects inside will feel different accelerations", de Matos says. Astronomers may have seen a similar violation of the principle (see "Two-speed gravity", below).

The odd acceleration detected in the niobium ring also suggests that energy isn't conserved in the superconductor – another major violation of known physics. Dark energy could solve that problem, however. "We did the sums and found out that energy wasn't conserved, but perhaps that was just because we were missing dark energy," de Matos says.

Paul Frampton, a cosmologist at the University of North Carolina at Chapel Hill, thinks Beck and Mackey's reasoning is flawed. "I don't think for a second they'll measure dark energy, but they should certainly try."

original article from NewScientist

This article seems to be driven by the hope that a puzzle of many wrong pieces still gives a good picture... I know Paul Frampton, a very reasonable guy, I hope he turns out to be right. Lesson learned: A correct paper is not a prerequisite to make it into the news.

powered by performancing firefox

NIAC may die soon

Nothing official yet, but the NewScientist reports that NASA might shut down the ACT "cousin" in the US ...

Will Biology Solve the Universe?

weird interview just read in wired ...

For years, scientists have tried to develop a universal theory of everything. Steven Hawking predicts that such a theory will be discovered in the next 20 years. A new theory asserts that biology, not physics, will be the key to unlocking the deepest mysteries of the universe, such as quantum mechanics.

"The answer to the universe is biology -- it's as simple as that," says Dr. Robert Lanza, vice president of research and scientific development at Advanced Cell Technology. He details his theory in The American Scholar's spring issue, published on Thursday. Lanza says scientists will establish a unified theory only if they radically rethink their understanding of space and time using a "biocentric" approach. His article is essentially a biological and philosophical response to Hawking's A Brief History of Time, in which he questions how we interpret the big bang, the existence of space and time, as well as many other theories -- assertions that might ruffle the feathers of some physical scientists.

(LS)

Robot swarms 'evolve' effective communication

Robot swarms 'evolve' effective communication


Robots that artificially evolve ways to communicate with one another have been demonstrated by Swiss researchers. The experiments suggest that simulated evolution could be a useful tool for those designing of swarms of robots.

Roboticists Dario Floreano, Sara Mitri, and Stéphane Magnenat at the Swiss Federal Institute of Technology in Lausanne collaborated with biologist Laurent Keller from the University of Lausanne.

They first evolved colonies of robots in software then tested different strategies on real bots, called s-bots. Both simulated and real robots were set loose in an arena containing two types of objects – one classified as "food" and another designated "poison" – both lit up red.

Each bot had a built-in attraction to food and aversion to poison. They also have a randomly-generated set of parameters, dubbed "genomes" that define the way they move, process sensory information, and how they flash their own blue lights.

"They start with completely random behaviour," Keller explains. "All they can do is discriminate food from poison." The robots can see both food or poison from a distance of several metres but can only tell them apart when almost touching.