Reversible tractor beam moves objects 100 times farther

Concept of photophoretic light–particle interaction in gases.

Credit: Nature Photonics (2014) doi:10.1038/nphoton.2014.242

A team of researchers working in Australia has built a tractor beam that bests the distance of other efforts a hundred fold, and it can both push and pull objects.

In their paper published in the journal Nature Photonics, the team describes their tractor beam project, how it works and what purpose it might serve.

A tractor beam is of course a beam emitted by a source that is used to hold and/or move another object.

The idea was popularized by the Star Trek series and other science fiction works, and was used typically by one starship to trap and move another starship.

In real life, physicists have made some inroads into developing a tractor beam (mostly based on the movement of photons to propel particles) but thus far, the objects trapped and moved have been extremely small and the distance moved even smaller.

In this new effort the researchers used a different technique to move an object that was bigger and to move it much farther, a hundred times as far.

Dr. Vladlen Shvedov (L) and Dr. Cyril Hnatovsky adjust the hollow laser beam in their lab at the Australian National University. 

Credit: Stuart Hay, ANU

The new tractor beam is based on heat, a laser that shines a doughnut-shaped beam (it has a cold center) was fired at a gold covered tiny (0.2mm diameter) glass bead that was small enough to just fit inside the beam, where it was cold.

The heat from the surrounding beam caused the surface of the bead to heat, creating hotspots.

When the hotspots came into contact with air particles, those particles were repelled, which in turn caused an opposing force against the glass bead, pushing it (up to a distance of 20cm).

The researchers found they could change the movement of the beads by adjusting the polarisation of the laser, causing changes in the hotspots on the beads.

That meant the beads could be pushed forward, stopped, pulled back, or held in place.

The team suggests their tractor beam could be useful in real world applications because of its versatility and because it requires just a single beam.

They believe it might be used for removing pollutants from the air, or for pulling undesirable particles from samples of materials.

They also note that it could very easily be made much larger, noting they were prevented from doing so by the small size of their lab.

More information: 
Economic tools for evaluating liabilities in environmental justice struggles, Nature Photonics (2014) DOI: 10.1038/nphoton.2014.242

CAN Revolutionary laser system produce the next LHC

An international team of physicists has proposed a revolutionary laser system, inspired by the telecommunications technology, to produce the next generation of particle accelerators, such as the Large Hadron Collider (LHC) in CERN.

The International Coherent Amplification Network (ICAN) sets out a new laser system composed of massive arrays of thousands of fibre lasers, for both fundamental research at laboratories such as CERN and more applied tasks such as proton therapy and nuclear transmutation.

Lasers can provide, in a very short time measured in femto-seconds, bursts of energy of great power counted in peta-watts or a thousand times the power of all the power plants in the world.

Compact accelerators are also of great societal importance for applied tasks in medicine, such as a unique way to democratise proton therapy for cancer treatment, or the environment where it offers the prospect to reduce the lifetime of dangerous nuclear waste by, in some cases, from 100 thousand years to tens of years or even less.

Major Difficulties
However, there are two major hurdles that prevent the high-intensity laser from becoming a viable and widely used technology in the future.

• First, a high-intensity laser often only operates at a rate of one laser pulse per second, when for practical applications it would need to operate tens of thousands of times per second.

• The second is ultra-intense lasers are notorious for being very inefficient, producing output powers that are a fraction of a percent of the input power. As practical applications would require output powers in the range of tens of kilowatts to megawatts, it is economically not feasible to produce this power with such a poor efficiency.

Technological Consortium
To bridge this technology divide, the ICAN consortium, an EU-funded project initiated and coordinated by the Ecole polytechnique and composed of the University of Southampton Optical Research Centre (ORC), Jena and CERN, as well as 12 other prestigious laboratories around the world, aims to harness the efficiency, controllability, and high average power capability of fibre lasers to produce high energy, high repetition rate pulse sources.

The aim is to replace the conventional single monolithic rod amplifier that typically equips lasers with a network of fibre amplifiers and telecommunication components.

Gerard Mourou

Gerard Mourou of Ecole polytechnique who leads the consortium says: "One important application demonstrated has been the possibility to accelerate particles to high energy over very short distances measured in centimetres rather than kilometres as it is the case today with conventional technology."

"This feature is of paramount importance when we know that today high energy physics is limited by the prohibitive size of accelerators, of the size of tens of kilometres, and cost billions of euros."

"Reducing the size and cost by a large amount is of critical importance for the future of high energy physics."

Dr Bill Brocklesby

Dr Bill Brocklesby from the ORC adds: "A typical CAN laser for high-energy physics may use thousands of fibres, each carrying a small amount of laser energy."

"It offers the advantage of relying on well tested telecommunication elements, such as fibre lasers and other components."

"The fibre laser offers an excellent efficiency due to laser diode pumping. It also provides a much larger surface cooling area and therefore makes possible high repetition rate operation."

"The most stringent difficulty is to phase the lasers within a fraction of a wavelength."

"This difficulty seemed insurmountable but a major roadblock has in fact been solved: preliminary proof of concept suggests that thousands of fibres can be controlled to provide a laser output powerful enough to accelerate electrons to energies of several GeV at 10 kHz repetition rate - an improvement of at least ten thousand times over today's state of the art lasers."

Such a combined fibre-laser system should provide the necessary power and efficiency that could make economical the production of a large flux of relativistic protons over millimetre lengths as opposed to a few hundred metres.

Societal Application
One important societal application of such a source is to transmute the waste products of nuclear reactors, which at present have half-lives of hundreds of thousands of years, into materials with much shorter lives, on the scale of tens of years, thus transforming dramatically the problem of nuclear waste management.

CAN technology could also find important applications in areas of medicine, such as proton therapy, where reliability and robustness of fibre technology could be decisive features.

Saturn's Moon Enceladus Particle Stream

This artist's concept shows a glowing patch of ultraviolet light near Saturn's north pole that occurs at the "footprint" of the magnetic connection between Saturn and its moon Enceladus. The magnetic field lines and the footprint are not visible to the naked eye, but were detected by the ultraviolet imaging spectrograph and fields and particles instruments on board NASA's Cassini spacecraft.
CREDIT: Ken Moscati and Abi Rymer, JHUAPL Including data from NASA/JPL/JHUAPL/University of Colorado/Central Arizona College/SSI

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A shimmering patch of light as big as Sweden detected at the north pole of Saturn is the spectacular result of a giant stream of electrically charged particles from the planet's moon Enceladus, scientists find.

On Earth, surges of charged particles from the sun colliding with our planet's magnetic field create the northern and southern lights, or auroras.

Similar patches of light have been seen on Jupiter, caused by electrons and ions originating from that planet's volcanically active moon Io.

Saturn also has its own aurora light show, which is created when solar particles from the sun interact with the planet's magnetic field. The new study, however, is the first time astronomers have caught a Saturn moon creating auroras on the ringed planet.

New Anti-matter Exotic Particle Found

In a single collision of gold nuclei at the RHIC particle accelerator, many hundreds of particles are emitted.

The particles leave telltale tracks in the STAR detector (shown here from the end and side).

Scientists analysed about a hundred million collisions to spot the new antinuclei, identified via their characteristic decay into a light isotope of antihelium and a positive pi-meson. Altogether, 70 examples of the new antinucleus were found. Credit: BNL

Scientists have created a never-before seen type of exotic matter that is thought to have been present at the earliest stages of the universe, right after the Big Bang.

The new matter is a particularly weird form of antimatter, which is like a mirror-image of regular matter. Every normal particle is thought to have an antimatter partner, and if the two come into contact, they annihilate.

The recent feat of matter-tinkering was accomplished by smashing charged gold atoms at each other at super-high speeds in a particle accelerator called the Relativistic Heavy Ion Collider at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory in Upton, N.Y.

Among the many particles that resulted from this crash were bizarre objects called anti-hypertritons. Not only are these things antimatter, but they're also what's called strange matter. Where normal atomic nuclei are made of protons and neutrons (which are made of "up" quarks and "down" quarks), strange nuclei also have so-called Lambda particles that contain another flavour of quark called "strange" as well. These Lambda particles orbit around the protons and neutrons.

If all that is a little much to straighten out, just think of anti-hypertritons as several kinds of weird.

Though they normally don't exist on Earth, these particles may be hiding in the universe in very hot, dense places like the centers of some stars, and most likely were around when the universe was extremely young and energetic, and all the matter was packed into a very small, sweltering space.

Scientists Create World's First Molecular Transistor

Scientists Create World's First Molecular Transistor

A group of scientists has succeeded in creating the first transistor made from a single molecule. The team, which includes researchers from Yale University and the Gwangju Institute of Science and Technology in South Korea, published their findings in the December 24 issue of the journal Nature.

The team, including Mark Reed, the Harold Hodgkinson Professor of engineering and Applied Science at Yale, showed that a benzene molecule attached to gold contacts could behave just like a silicon transistor.

The researchers were able to manipulate the molecule's different energy states depending on the voltage they applied to it through the contacts. By manipulating the energy states, they were able to control the current passing through the molecule.

"It's like rolling a ball up and over a hill, where the ball represents electrical current and the height of the hill represents the molecule's different energy states," Reed said. "We were able to adjust the height of the hill, allowing current to get through when it was low, and stopping the current when it was high." In this way, the team was able to use the molecule in much the same way as regular transistors are used.

LHC sets new world record for energy particle accelarator

CERN's Large Hadron Collider has today become the world's highest energy particle accelerator, having accelerated its twin beams of protons to an energy of 1.18 TeV in the early hours of the morning.

This exceeds the previous world record of 0.98 TeV, which had been held by the US Fermi National Accelerator Laboratory's Tevatron collider since 2001. It marks another important milestone on the road to first physics at the LHC in 2010.

"We are still coming to terms with just how smoothly the LHC commissioning is going," said CERN Director General Rolf Heuer. "It is fantastic. However, we are continuing to take it step by step, and there is still a lot to do before we start physics in 2010. I'm keeping my champagne on ice until then."

These developments come just 10 days after the LHC restart, demonstrating the excellent performance of the machine. First beams were injected into the LHC on Friday 20 November.

Over the following days, the machine's operators circulated beams around the ring alternately in one direction and then the other at the injection energy of 450 GeV, gradually increasing the beam lifetime to around 10 hours. On Monday 23 November, two beams circulated together for the first time, and the four big LHC detectors recorded their first collision data.

Last night's achievement brings further confirmation that the LHC is progressing smoothly towards the objective of first physics early in 2010. The world record energy was first broken yesterday evening, when beam 1 was accelerated from 450 GeV, reaching 1050 GeV (1.05 TeV) at 21:28, Sunday 29 November. Three hours later both LHC beams were successfully accelerated to 1.18 TeV, at 00:44, 30 November.

"I was here 20 years ago when we switched on CERN's last major particle accelerator, LEP," said Research and Technology Director Steve Myers. "I thought that was a great machine to operate, but this is something else. What took us days or weeks with LEP, we're doing in hours with the LHC. So far, it all augurs well for a great research program."

Next on the schedule is a concentrated commissioning phase aimed at increasing the beam intensity before delivering good quantities of collision data to the experiments before Christmas. So far, all the LHC commissioning work has been carried out with a low intensity pilot beam. Higher intensity is needed to provide meaningful proton-proton collision rates.

The current commissioning phase aims to make sure that these higher intensities can be safely handled and that stable conditions can be guaranteed for the experiments during collisions. This phase is estimated to take around a week, after which the LHC will be colliding beams for calibration purposes until the end of the year.

Prof John Womersley, Director Science Programmes at STFC said; "this is another fantastic milestone for the LHC. To see such a complex project make progress at this impressive rate is testament to the tremendous efforts that have been made by all of those involved. I look forward to seeing the continued success of the LHC and to early 2010 when we can expect it to deliver the first data for physics analysis".

First physics at the LHC is scheduled for the first quarter of 2010, at a collision energy of 7 TeV (3.5 TeV per beam).