Seeing Light in a New Light: Scientists Create Never-Before-Seen Form of Matter
Harvard and MIT scientists are challenging the conventional wisdom about light, and they didn't need to go to a galaxy far, far away to do it.
Working with colleagues at the Harvard-MIT Center for Ultracold Atoms, a group led by Harvard Professor of Physics Mikhail Lukin and MIT Professor of Physics Vladan Vuletic have managed to coax photons into binding together to form molecules -- a state of matter that, until recently, had been purely theoretical. The work is described in a September 25 paper in Nature.
The discovery, Lukin said, runs contrary to decades of accepted wisdom about the nature of light. Photons have long been described as massless particles which don't interact with each other -- shine two laser beams at each other, he said, and they simply pass through one another.
"Photonic molecules," however, behave less like traditional lasers and more like something you might find in science fiction -- the light saber.
"Most of the properties of light we know about originate from the fact that photons are massless, and that they do not interact with each other," Lukin said. "What we have done is create a special type of medium in which photons interact with each other so strongly that they begin to act as though they have mass, and they bind together to form molecules. This type of photonic bound state has been discussed theoretically for quite a while, but until now it hadn't been observed.
"It's not an in-apt analogy to compare this to light sabers," Lukin added. "When these photons interact with each other, they're pushing against and deflect each other. The physics of what's happening in these molecules is similar to what we see in the movies."
To get the normally-massless photons to bind to each other, Lukin and colleagues, including Harvard post-doctoral fellow Ofer Fisterberg, former Harvard doctoral student Alexey Gorshkov and MIT graduate students Thibault Peyronel and Qiu Liang couldn't rely on something like the Force -- they instead turned to a set of more extreme conditions.
Researchers began by pumped rubidium atoms into a vacuum chamber, then used lasers to cool the cloud of atoms to just a few degrees above absolute zero. Using extremely weak laser pulses, they then fired single photons into the cloud of atoms.
As the photons enter the cloud of cold atoms, Lukin said, its energy excites atoms along its path, causing the photon to slow dramatically. As the photon moves through the cloud, that energy is handed off from atom to atom, and eventually exits the cloud with the photon.
"When the photon exits the medium, its identity is preserved," Lukin said. "It's the same effect we see with refraction of light in a water glass. The light enters the water, it hands off part of its energy to the medium, and inside it exists as light and matter coupled together, but when it exits, it's still light. The process that takes place is the same it's just a bit more extreme -- the light is slowed considerably, and a lot more energy is given away than during refraction."
When Lukin and colleagues fired two photons into the cloud, they were surprised to see them exit together, as a single molecule.
The reason they form the never-before-seen molecules?
An effect called a Rydberg blockade, Lukin said, which states that when an atom is excited, nearby atoms cannot be excited to the same degree. In practice, the effect means that as two photons enter the atomic cloud, the first excites an atom, but must move forward before the second photon can excite nearby atoms.
The result, he said, is that the two photons push and pull each other through the cloud as their energy is handed off from one atom to the next.
"It's a photonic interaction that's mediated by the atomic interaction," Lukin said. "That makes these two photons behave like a molecule, and when they exit the medium they're much more likely to do so together than as single photons."
While the effect is unusual, it does have some practical applications as well.
"We do this for fun, and because we're pushing the frontiers of science," Lukin said. "But it feeds into the bigger picture of what we're doing because photons remain the best possible means to carry quantum information. The handicap, though, has been that photons don't interact with each other."
To build a quantum computer, he explained, researchers need to build a system that can preserve quantum information, and process it using quantum logic operations. The challenge, however, is that quantum logic requires interactions between individual quanta so that quantum systems can be switched to perform information processing.
"What we demonstrate with this process allows us to do that," Lukin said. "Before we make a useful, practical quantum switch or photonic logic gate we have to improve the performance, so it's still at the proof-of-concept level, but this is an important step. The physical principles we've established here are important."
The system could even be useful in classical computing, Lukin said, considering the power-dissipation challenges chip-makers now face. A number of companies -- including IBM -- have worked to develop systems that rely on optical routers that convert light signals into electrical signals, but those systems face their own hurdles.
Lukin also suggested that the system might one day even be used to create complex three-dimensional structures -- such as crystals -- wholly out of light.
"What it will be useful for we don't know yet, but it's a new state of matter, so we are hopeful that new applications may emerge as we continue to investigate these photonic molecules' properties," he said.
Vindskip (or Windship) and it could achieve fuel savings Of60%AndReduceEmissionsBy80%
Of the exciting tech stories to cross our desk this week, innovations that help people get from point A to B stand out. Take for example, a young man who made an elevator from a bicycle, or a group of researchers who designed an RFID ring that gives the wearer access to a subway, or virtual simulation of Elon Musk's Hyperloop that shows it could work or a wind-powered ship that has a hull that works as an airfoil. Read on.
Norwegian designers at Lade AS have designed a unique ship that they say would achieve fuel savings of 60 percent and reduce emissions by 80 percent. Their Vindskip (or Windship) has a specially designed hull that works like a symmetrical airfoil harnessing wind somewhat like the wing of a plane to generate "lift." The ship would also use a liquefied natural gas-powered electrical generator for additional power.
Solar panels could destroy U.S. utilities, according to U.S. utilities
That is not wild-eyed hippie talk. It is the assessment of the utilities themselves.
Back in January, the Edison Electric Institute — the (typically stodgy and backward-looking) trade group of U.S. investor-owned utilities — released a report [PDF] that, as far as I can tell, went almost entirely without notice in the press. That’s a shame. It is one of the most prescient and brutally frank things I’ve ever read about the power sector. It is a rare thing to hear an industry tell the tale of its own incipient obsolescence.
Scientists Have Found The First Concrete Reason Why We Need Sleep
We know we need to sleep. We know our brains and bodies work better after sleep. But what we didn’t know, until now, was why.
Scientists have just reported the first major mechanical reason our brains need to sleep — certain cleaning mechanisms in the brain work better when we shut the brain down.
Just like how dump trucks take to the city streets during the pre-dawn hours because there’s less traffic, our brain’s cleaners also work best when there’s less going on.
“This study shows that the brain has different functional states when asleep and when awake,” study researcher Maiken Nedergaard, of the University of Rochester said.
“In fact, the restorative nature of sleep appears to be the result of the active clearance of the by-products of neural activity that accumulate during wakefulness.”
We’ve known that our brains consolidate memories during sleep and perform other important functions.
There are also benefits to the body during sleep — resting allows our muscles, bones, and organs to repair themselves.
It also keeps our immune system healthy.
We know that sleep has all of these benefits, but until now we didn’t know any of the specific changes that bring about these sleep benefits.
Charles Czeisler, a sleep researcher at Harvard Medical School in Boston, told Science Magazine’s Emily Underwood that this is the “ﬁrst direct experimental evidence at the molecular level” for why we need to sleep.
The paper was published in the journal Science on Oct. 17.
All of our cells accumulate waste while they are working, and these waste products can be toxic. If they aren’t removed they can build up and kill our cells. Throughout the rest of the body the lymphatic system washes these waste products away, but the brain is cut off from these actions because of the blood-brain barrier.
He walks, he talks and he has a beating heart, but he's not human — he's the world's first fully bionic man.
Like Frankenstein's monster, cobbled together from a hodgepodge of body parts, the bionic man is an amalgam of the most advanced human prostheses — from robotic limbs to artificial organs to a blood-pumping circulatory system.
The creature "comes to life" in "The Incredible Bionic Man," premiering Sunday (Oct. 20) on the Smithsonian Channel at 9 p.m. EDT/8 p.m. CDT.
Roboticists Rich Walker and Matthew Godden of Shadow Robot Co. in England led the assembly of the bionic man from prosthetic body parts and artificial organs donated by laboratories around the world.
"Our job was to take the delivery of a large collection of body parts — organs, limbs, eyes, heads — and over a frantic six weeks, turn those parts into a bionic man," Walker told LiveScience during an interview. But it's not as simple as connecting everything like Tinkertoys. "You put a prosthetic part on a human who is missing that part," Walker said. "We had no human; we built a human for the prosthetic parts to occupy."
The robot, which cost almost $1 million to build, was modeled in some physical aspects after Bertolt Meyer, a social psychologist at the University of Zurich, in Switzerland, who wears one of the world's most advanced bionic hands. [See Photos of the Bionic Man]
The bionic man has the same prosthetic hand as Meyer — the i-LIMB made by Touch Bionics — with a wrist that can fully rotate and motors in each finger. The hand's grasping abilities are impressive, but the bionic man still drops drinks sometimes.
"He's not the world's best bartender," Walker said.
The robot sports a pair of robotic ankles and feet from BiOM in Bedford, Mass., designed and worn by bioengineer Hugh Herr of MIT's Media Lab, who lost his own legs after getting trapped in a blizzard as a teenager.
To support his prosthetic legs, the bionic man wears a robotic exoskeleton dubbed "Rex," made by REX Bionics in New Zealand. His awkward, jerky walk makes him more Frankensteinian than ever.
In recent years, astronomers have discovered a host of strange worlds—they discovered a planet that has a year that is only 4 Earth-hours long, and another that seems to be made almost entirely of diamond. Now, we have another strange planet to add to this list: Gliese 1214 b. This alien planet is nearly six times the size of the Earth, which means that the planet finds itself somewhere between the Earth and our solar system’s ice giants (Uranus and Neptune) in size. What’s more, it is covered with a water-rich atmosphere. That sounds promising, doesn’t it? At first glance, maybe. It is a huge planet with an abundance of water; however, this planet seems to include a strange “plasma form” of water.
Ultimately, it is the high temperature and density of the planet that gives it an atmosphere that is so dramatically different from the atmosphere found on Earth. For starters, Gliese 1214 b orbits its star once every 38 hours, making it 70 times closer than Earth is to the Sun. Since it is so close, the temperatures on the planet reach up to 540 degrees Fahrenheit (280 degrees Celsius), which is a little warm for most all Earth-based life.
Isaac Newton just got cheated. Laser pulses have been made to accelerate themselves around loops of optical fibre, seeming to break the physicist's law that every action must have an equal and opposite reaction. The work exploits a trick with light that only makes it appear to have mass, so it is a bit of a cheat, but it may one day lead to faster electronics and more reliable communications.
According to Newton's third law of motion, when one billiard ball strikes another, the two balls should bounce away from each other. But if one of the billiard balls had a negative mass, then when the two balls collide they will accelerate in the same direction. This effect could be useful in a diametric drive, a speculative "engine" in which negative and positive mass interact to accelerate forever. NASA explored using the effect in the 1990s in a bid to make a diametric drive for better spacecraft propulsion. But there was a very big fly in the ointment: quantum mechanics states that matter cannot have a negative mass. Even antimatter, made of particles with the opposite charge and spin to their normal matter counterparts, has positive mass.
"Writing a negative mass in quantum field theory doesn't make any difference," says Archil Kobakhidze at the University of Sydney, Australia. The equations involve terms that are always squares of mass, so any negative mass will become positive anyway. "It has no observable meaning."
Marmoset monkeys take it in turns to "talk" in a pattern very similar to human conversation, according to scientists.
Researchers recorded the sounds of the marmosets as they called to one another from behind a curtain.
Each animal would call, then wait for the other to respond before calling again.
The results suggest an "alternative evolutionary route" for our own conversational turn-taking.
They are reported in the journal Current Biology.
It is something we take for granted in our conversations, but taking it in turns to talk and listen is crucial for us to effectively exchange information through what we say.
Somewhat mysteriously though, we do not see an obvious origin in our closest primate relatives - the chimpanzees.
Chimps are not very vocal and tend to use their repertoire of gestures to communicate, so it is widely accepted that these manual gestures provided the foundations for the co-operation inherent in our own communication.
But Dr Asif Ghazanfar from Princeton University set out to look for evidence of a vocal route for this co-operation, by looking at vocal exchanges in marmosets.
He explained that he chose marmosets precisely because, unlike chimps, they are very vocal.
It is one of two main characteristics the monkeys share with humans, Dr Ghazanfar said.
"They're [also] co-operative breeders - so they help one another take care of their offspring.
"That's an important characteristic because it leads to greater pro-sociality (meaning the animals, like us, carry out behaviours that are intended to benefit others)."
Scientists Create an Organism with a New Genetic Code
For the first time, scientists have fundamentally changed the genetic code of an organism, raising the possibility that researchers might be able to retool nature and create potent new forms of proteins to combat disease.
Scientists from Yale and Harvard have recoded the entire genome of an organism and improved a bacterium’s ability to resist viruses, a dramatic demonstration of the potential of rewriting an organism’s genetic code.
“This is the first time the genetic code has been fundamentally changed,” said Farren Isaacs, assistant professor of molecular, cellular, and developmental biology at Yale and co-senior author of the research published October 18 in the journal Science. “Creating an organism with a new genetic code has allowed us to expand the scope of biological function in a number of powerful ways.”
Science has made leaps with 3D printing, perhaps one of the most astounding technological advances in recent years. As we’ve seen, scientists have been able to develop functioning organs, bones and tissue using a person’s own stem cells, prosthetic limbs, 3D printed guns that can withstand the force of firing a bullet and cars (among many other things). Hell, 3D printers can even print other 3D printers, which could have some cool implications for using the technology to build the first human base on the moon or Mars. The sky is the limit.
In recent news, a team of researchers have combined two awesome technologies into an exceptionally exciting product: an invisibility cloak created by a 3D printer — the very first of its kind. (Harry Potter, anyone?) The team, who hail from Duke University, released the first prototype more than seven years ago, with the newest design unveiled several months ago, which looks rather unimpressive (particularly, it looks like a Frisbee composed of Swiss cheese) on the surface.
So, how does it work? It’s actually kind of simple. Algorithms are used to determine the size, location and shape of the holes in the polymer circular-Frisbee design, which is open in the center, needed to deflect microwave beams (the only thing that can be deflected by this particular proto-type). An opaque object is placed in the center, after which, microwave beams are aimed and ejected at the device from the side of the disk, cloaking the object in the center, making it disappear from sight. Ultimately, “the microwaves are re-radiated back into free space on the shadow side of the cloak.”
It took as few as three lionfish to start the invasion.
Or at least, that's the best guess. Genetic tests show that there weren't many. No one knows how the fish arrived. They might have escaped into Florida's waters in 1992, when Hurricane Andrew capsized many transport boats. Or they might have been imported as an aquarium curiosity and later released.
But soon those lionfish began to breed a dynasty. They laid hundreds of gelatinous eggs that released microscopic lionfish larvae. The larvae drifted on the current. They grew into adults, capable of reproducing every 55 days and during all seasons of the year. The fish, unknown in the Americas 30 years ago, settled on reefs, wrecks and ledges. And that's when scientists, divers and fishermen began to notice.
In 2000, a recreational diver saw two tropical lionfish clinging improbably to the submerged ruins of a tanker off the coast of North Carolina, nearly 140 feet below the surface. She alerted the National Oceanographic and Atmospheric Administration, which started tracking lionfish sightings in the Atlantic. Within two years, the fish had been seen in Georgia, Florida, Bermuda and the Bahamas. They are now known to live from Rhode Island to Belize.
"I've never seen any fish colonize so quickly over such a vast geographic range," says Paula Whitfield, a fisheries biologist at NOAA.
Lionfish are the first exotic species to invade coral reefs. They have multiplied at a rate that is almost unheard of in marine history, going from nonexistent to pervasive in just a few short years. Along the way, they've eaten or starved out local fish, disrupted commercial fishing, and threatened the tourism industry. Some experts believe that lionfish are so widespread that their effect on the ecosystems of the Western Atlantic will be almost impossible to reverse. Still, some people are determined to try, if only to protect those waters which haven't yet been invaded.
Lionfish are native to the warm tropical waters of the Indian and South Pacific Oceans, nearly 10,000 miles away from the Florida shore. There are many species of lionfish in the world's oceans, and they can be hard to tell apart. All the lionfish identified in the Bahamas have been Pterois volitans, and the species is now common throughout the Western Atlantic, but some closely related Pterois miles have been found as well. Scientists don't know which species was the first to invade, but both invasions started small: genetic tests of the two species in the Atlantic show very little genetic diversity.
Lionfish grow up to a foot long and sport candy cane stripes. Their sharp spines contain a powerful venom. Although a single prick from a lionfish spine can cause days of swelling, discomfort and even paralysis, Americans import thousands of lionfish every year for aquarium use.
Killer Robots With Automatic Rifles Could Be on the Battlefield in 5 Years
Robots armed with automatic weapons, anti-tank missiles and even grenade launchers are marching, er, rolling ever closer to the battlefield now that they’ve shown they can actually hit what they’re supposed to.
Four robotics companies — HDT Robotics, iRobot, Northrop Grumman and QinetiQ — recently ran their M240 machine gun-armed robots through a live-fire demo at Fort Benning in what has been dubbed the “Robotic Rodeo.” The point was to give the brass a chance to see just how viable such systems are.
The Army, which issued a favorable assessment of the technology last week, doesn’t see our armed robotic overlords as weapons taking the place of boots on the ground, but rather as combatants working alongside troops in the field.
“They’re not just tools, but members of the squad. That’s the goal,” Lt. Col. Willie Smith, chief of Unmanned Ground Vehicles at Fort Benning told Computerworld. “A robot becoming a member of the squad, we see that as a matter of training.”
Senior Army officers attending the rodeo appeared satisfied with the robots after seeing them accurately hit targets 500 feet away, and they hope to see battle ‘bots in action within five years.
“We were hoping to see how they remotely control lethal weapons,” said Smith. “We were pleased with what we saw here. The technology is getting to be where it needs to be.”
This isn’t the first time the Pentagon has played with weaponized robots, but earlier experiments proved such machines weren’t ready for primetime after some of them moved without commands.
Northrop Grumman’s CaMEL (Carry-all Mechanized Equipment Landrover), among the armed robots at the rodeo, can be fitted with automatic weapons, anti-tank missiles and grenade launchers. It can run for more than 20 hours on 3.5 gallons of fuel, according to the company, and carry a load of 1,000 pounds. It also can produce power to charge batteries or power other systems.
Clues to Lost Prehistoric Code Discovered in Mesopotamia
Peering inside prehistoric clay balls
Pin It Archaeologists are using CT scanning and 3D modelling to crack a lost prehistoric code hidden inside clay balls, dating to some 5,500 years ago, found in Mesopotamia.
Credit: Anna Ressman/Courtesy Oriental Institute of the University of Chicago.
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Researchers studying clay balls from Mesopotamia have discovered clues to a lost code that was used for record-keeping about 200 years before writing was invented.
The clay balls may represent the world's "very first data storage system," at least the first that scientists know of, said Christopher Woods, a professor at the University of Chicago's Oriental Institute, in a lecture at Toronto's Royal Ontario Museum, where he presented initial findings.
The balls, often called "envelopes" by researchers, were sealed and contain tokens in a variety of geometric shapes — the balls varying from golf ball-size to baseball-size. Only about 150 intact examples survive worldwide today.