Light’s Most Exotic Trick Yet: So Fast it Goes … Backwards?

In the past few years, scientists have found ways to make light go both faster and slower than its usual speed limit, but now researchers at the University of Rochester have published a paper today in Science on how they’ve gone one step further: pushing light into reverse. As if to defy common sense, the backward-moving pulse of light travels faster than light.

Confused? You’re not alone.

“I’ve had some of the world’s experts scratching their heads over this one,” says Robert Boyd, the M. Parker Givens Professor of Optics at the University of Rochester. “Theory predicted that we could send light backwards, but nobody knew if the theory would hold up or even if it could be observed in laboratory conditions.”

Boyd recently showed how he can slow down a pulse of light to slower than an airplane, or speed it up faster than its breakneck pace, using exotic techniques and materials. But he’s now taken what was once just a mathematical oddity—negative speed—and shown it working in the real world.

ScienceBlog

Towards Gravity Generation?

Scientists funded by the European Space Agency have measured the gravitational equivalent of a magnetic field for the first time in a laboratory. Under certain special conditions the effect is much larger than expected from general relativity and could help physicists to make a significant step towards the long-sought-after quantum theory of gravity.

The research demonstrates that a superconductive gyroscope is capable of generating a powerful gravitomagnetic field, and is therefore the gravitational counterpart of the magnetic coil. Depending on further confirmation, this effect could form the basis for a new technological domain, which would have numerous applications in space and other high-tech sectors” says Clovis de Matos, ESA-HQ, Paris.

Although just 100 millionths of the acceleration due to the Earth’s gravitational field, the measured field is a surprising one hundred million trillion times larger than Einstein’s General Relativity predicts.

European Space Agency

The Geometrization Of Thought

F. David Peat

As a result of the popular books and magazine articles that have appeared over the last few years the topic of chaos theory has become familiar to many people. While some psychologists may not be comfortable with the mathematical details of the theory they are probably acquainted with its broad outlines and general concepts. Thus, for example, the image of “butterfly effect” is often applied to systems so extraordinary sensitive that a perturbation as small as the flapping of a butterfly’s wings produces a large scale change of behavior. While chaos theory holds that such systems remain strictly deterministic they are, nevertheless, so enormously complex that the exact details of their behavior are, in practice, unpredictable even with the aid of the largest computers.

On the other hand, since such systems remain within the grip of their strange attractor while the details of their fluctuations appear to be random, nevertheless, their chaos is contained within a particular range of all possible behaviors. Their dynamics may, for example, exhibit a fractal structure in which similar patterns are repeated at smaller and smaller scales of space and intervals of time. As an example, while it is impossible to predict the exact value of a particular share on the stock market at an arbitrary date in the future one may be able to say something about its general pattern of fluctuation over a month, day or even an hour.

In a sense, therefore, chaos theory is something of a misnomer for it is not so much the study of systems in which all order has broken down in favour of pure chance but rather of those which exhibit extremely high degrees of order involving very subtle and sensitive behavior. The full description of such systems would require an enormous, potentially an infinite, amount of information. On the other hand, highly complex behavior can sometimes be simulated in very simple ways through the constant repetition of an iterative processes such as Prigogine’s baker’s transformation or the non-linear feedback associated with the changing size of insect populations.

While chaos theory and fractal descriptions are capable of simulating a wide variety of natural processes it remains an open question as to the extent to which such theories actually offer a full account of the inner workings of nature and society. For example, while repeated iterations can generate complex results this does not necessarily mean that such iterations are part of the actual generative processes of nature itself. Another pertinent question is to what extend dues absolute randomness and chaos occurs within the universe. While chaos theory is purely deterministic may there exist certain natural processes that are essentially chaotic, indeterministic and random? Quantum theory would be an obvious choice, for the time at which a radioactive nucleus disintegrates is, according to the theory, absolutely indeterministic – it is a matter of pure chance. David Bohm, however, has produced a deterministic version of quantum theory which perfectly accounts for all the empirical findings and predictions of the theory without invoking the assumption of absolute chance.

Another area in which intrinsic randomness occurs is in the sequence of digits of an irrational number. But what is the ontological basis of such numbers in nature? Are they a manifestation of intrinsic randomness in the universe or do they represent the abstract limits of processes that involve an infinite amount of information? At present there seems to be no way of deciding whether pure chance and randomness plays a role in the cosmos or if all systems are essentially deterministic in nature.

future positive

10 Atom Thick Circuits Manipulate Electron Waves

Using thin layers of graphite known as graphene, researchers have produced proof-of-principle transistors, loop devices and circuitry. The devices have the attractive properties of carbon nanotubes but could be produced using established microelectronics manufacturing techniques.

Ultimately, the researchers at the Georgia Institute of Technology in the United States, in collaboration with the Centre National de la Recherche Scientifique, hope to use graphene layers less than 10 atoms thick as the basis for revolutionary electronic systems that would manipulate electrons as waves rather than particles, much like photonic systems control light waves.

KurzweilAI

Bubble Fusion: Silencing the Hype

Taken together, the overall message from many people close to this work is that there is no longer any hope that this line of publications will yield a viable fusion energy source. For some this is almost liberating: those sticking with bubble fusion are freer than ever to explore other approaches to it, or to try other kinds of studies on acoustic chambers and the behaviour of collapsing bubbles. For others it is now the end of bubble fusion. There are other kinds of science to be done.

nature
a response from Taleyarkhan

Light Powered Quantum Computers?

Ohio University scientists who hope to use quantum dots as the building blocks for the next generation of computers have found a way to make these artificial atoms communicate.

They found that when the dots were arranged at a distance from each other greater than the radius of the dots, light waves traveled between the nanocrystals coherently. In previous research, the light’s wavelength would change or become irregular during the energy exchange, which creates a breakdown in communication between quantum dots.

The results suggest that there could be a way to transmit information using light waves, laying the groundwork for a possible optical quantum computer.

The applications of the new quantum dot technology also could include medical imaging. Quantum dots could be injected into the patient, and a device containing more quantum dots could be used to show the position of dots under the skin.

KurzweilAI < OhioU

More Easy Fusion Technology

Researchers at Rensselaer Polytechnic Institute have developed a tabletop accelerator that produces nuclear fusion at room temperature, providing confirmation of an earlier experiment conducted at the University of California, Los Angeles (UCLA), while offering substantial improvements over the original design.

The device, which uses two opposing crystals to generate a powerful electric field, could potentially lead to a portable, battery-operated neutron generator for a variety of applications, from non-destructive testing to detecting explosives and scanning luggage at airports. The new results are described in the Feb. 10 issue of Physical Review Letters.

“Our study shows that ‘crystal fusion’ is a mature technology with considerable commercial potential,” says Yaron Danon, associate professor of mechanical, aerospace, and nuclear engineering at Rensselaer. “This new device is simpler and less expensive than the previous version, and it has the potential to produce even more neutrons.”

The device is essentially a tabletop particle accelerator. At its heart are two opposing “pyroelectric” crystals that create a strong electric field when heated or cooled. The device is filled with deuterium gas — a more massive cousin of hydrogen with an extra neutron in its nucleus. The electric field rips electrons from the gas, creating deuterium ions and accelerating them into a deuterium target on one of the crystals. When the particles smash into the target, neutrons are emitted, which is the telltale sign that nuclear fusion has occurred, according to Danon.

Rensselaer>

New Transistor Uses Single Electrons

Scientists have demonstrated the first reproducible, controllable silicon transistors that are turned on and off by the motion of individual electrons. The experimental devices, designed and fabricated at NTT Corp. of Japan and tested at NIST, may have applications in low-power nanoelectronics, particularly as next-generation integrated circuits for logic operations (as opposed to simpler memory tasks).

The transistors, described in the Jan. 30, 2006, issue of Applied Physics Letters,* are based on the principle that as device sizes shrink to the nanometer range, the amount of energy required to move a single electron increases significantly. This makes it possible to control individual electron motion and current flow by manipulating the voltage applied to barriers, or “gates,” in the electrical circuit. At negative voltage, the transistor is off; at higher voltage, the transistor is turned on and individual electrons file through the circuit, as opposed to thousands at a time in a conventional device.

ScienceBlog

Sonofusion Passes the Test!

A team of researchers from Rensselaer Polytechnic Institute, Purdue University, and the Russian Academy of Sciences has used sound waves to induce nuclear fusion without the need for an external neutron source, according to a paper in the Jan. 27 issue of Physical Review Letters. While this doesn’t mean enormous amounts of inexpensive energy, it is a step in the right direction.

The results address one of the most prominent questions raised after publication of the team’s earlier results in 2004, suggesting that “sonofusion” may be a viable approach to producing neutrons for a variety of applications.

By bombarding a special mixture of acetone and benzene with oscillating sound waves, the researchers caused bubbles in the mixture to expand and then violently collapse. This technique, which has been dubbed “sonofusion,” produces a shock wave that has the potential to fuse nuclei together, according to the team.

PhysOrg

South Pole Neutrino Detector Could Yield Evidences of String Theory

Researchers at Northeastern University and the University of California, Irvine say that scientists might soon have evidence for extra dimensions and other exotic predictions of string theory. Early results from a neutrino detector at the South Pole, called AMANDA, show that ghostlike particles from space could serve as probes to a world beyond our familiar three dimensions, the research team says.

No more than a dozen high-energy neutrinos have been detected so far. However, the current detection rate and energy range indicate that AMANDA’s larger successor, called IceCube, now under construction, could provide the first evidence for string theory and other theories that attempt to build upon our current understanding of the universe.

An article describing this work appears in the current issue of Physical Review Letters. The authors are: Luis Anchordoqui, associate research scientist in the Physics Department at Northeastern University; Haim Goldberg, professor in the Physics Department at Northeastern University; and Jonathan Feng, associate professor in the Department of Physics and Astronomy at University of California, Irvine.

PhysOrg

Gravity theory dispenses with dark matter

A modified theory of gravity that incorporates quantum effects can explain a trio of puzzling astronomical observations – including the wayward motion of the Pioneer spacecraft in our solar system, new studies claim.

The work appears to rule out the need to invoke dark matter or another alternative gravity theory called MOND (Modified Newtonian Dynamics). But other experts caution it has yet to pass the most crucial test – how to account for the afterglow of the big bang.

New Scientist Space via /.

Einstein’s ‘Spooky Action’ In a Chip

A simple semiconductor chip has been used to generate pairs of entangled photons, a vital step towards making quantum computers a reality.

Famously dubbed “spooky action at a distance” by Einstein, entanglement is the mysterious phenomenon of quantum particles whereby two particles such as photons behave as one regardless of how far apart they are. It is widely regarded as essential to the development of quantum computers and quantum cryptography.

NewScientist

Cold Fusion for Real?

Can the popping of tiny bubbles trigger nuclear fusion, a potential source of almost unlimited energy? This controversial idea is back on the table, because its main proponent has new results that, he claims, will silence critics. But others say that the latest experiment simply comes with its own set of problems.

The idea is simple enough. Blast a liquid with waves of ultrasound and tiny bubbles of gas are created, which release a burst of heat and light when they implode. The core of the bubble reaches 15,000 °C, hot enough to wrench molecules apart. Physicists have even suggested that the intense conditions of this sonoluminescence could fuse atomic nuclei together, in the same process that keeps our Sun running.

Physicist Rusi Taleyarkhan of Purdue University in West Lafayette, Indiana, published the first evidence1 of this ‘sonofusion’ in 2002; he has been dogged by sceptics ever since.

The underlying physics behind the idea is valid, says Ken Suslick. An expert in sonoluminescence at the University of Illinois in Urbana-Champaign, Suslick tried and failed to replicate Taleyarkhan’s first results. If the bubbles’ collapse is sufficiently intense, it should indeed be able to crush atoms together. Taleyarkhan just hasn’t done enough to prove it, says Suslick.

Nature

Quantum Communication

A trick for transferring quantum information from atoms to photons and back again could be used to create impenetrable global communication networks and computers that work at astounding speeds.

Two research groups, one led by Mikhail Lukin at Harvard University and the second headed by Alex Kuzmich of Georgia Institute of Technology, both in the US, separately demonstrated the feat using similar methods.

Both teams employed powerful laser pulses to extract quantum information from a cloud of atoms in the form of a single photon. That photon was then transmitted through a normal optical fibre before its quantum state was transferred to a second atomic cloud.

Creating communication links between such “quantum memories” – the clouds of atoms – is crucial to building complex networks that exploit quantum phenomena, such as entanglement and superposition. Quantum networks are extremely sensitive to interference, but hold great promise for secure communications and superfast computing.

New Scientist

Spin-Mediated Consciousness Theory: Possible Roles of Oxygen Unpaired Electronic Spins and Neural Membrane Nuclear Spin Ensemble in Memory and Consciousness

by Huping Hu, Maoxin Wu

We postulate that consciousness is connected to quantum mechanical spin since said spin is embedded in the microscopic structure of spacetime and may be more fundamental than spacetime itself. Thus, we theorize that consciousness is connected with the fabric of spacetime through spin. That is, spin is the “pixel” and “antenna” of mind. The unity of mind is achieved by non-local means within the pre-spacetime domain interfaced with spacetime. Human mind is possible because of the particular structures and dynamics of our brain postulated working as follows: The unpaired electronic spins of highly lipid-soluble and rapidly diffusing oxygen molecules extract information from the dynamical neural membranes and communicate said information through strong spin-spin couplings to the nuclear spin ensemble in the membranes for consciousness-related quantum statistical processing which survives decoherence. In turn, the dynamics of the nuclear spin ensemble has effects through spin chemistry on the classical neural activities such as action potentials and receptor functions thus connecting with the classical neural networks of the brain. Our proposal calls for associative encoding of neural memories in the dynamical structures of neural membranes. Thus, according to the present theory: (1)the dynamical nuclear spin ensemble is the “pixels” of mind; (2) the neural membranes are the pixel-embedding and associative memory storage matrices; and (3) the unpaired electrons of the rapidly diffusing oxygen molecules are the spin beam for information retrieval, communication and pixel-activation. Together, they form the interface (neural substrates) to consciousness.

MindPixel < QuantumBrain