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Saturday, January 22, 2011

Physicist Discovers How to Teleport Energy

http://www.technologyreview.com/blog/arxiv/24759/

Physicist Discovers How to Teleport Energy

First, they teleported photons, then atoms and ions. Now one physicist has worked out how to do it with energy, a technique that has profound implications for the future of physics.
kfc 02/03/2010
  • 118 Comments
In 1993, Charlie Bennett at IBM's Watson Research Center in New York State and a few pals showed how to transmit quantum information from one point in space to another without traversing the intervening space.
The technique relies on the strange quantum phenomenon called entanglement, in which two particles share the same existence. This deep connection means that a measurement on one particle immediately influences the other, even though they are light-years apart. Bennett and company worked out how to exploit this to send information. (The influence between the particles may be immediate, but the process does not violate relativity because some informatiom has to be sent classically at the speed of light.) They called the technique teleportation.
That's not really an overstatement of its potential. Since quantum particles are indistinguishable but for the information they carry, there is no need to transmit them themselves. A much simpler idea is to send the information they contain instead and ensure that there is a ready supply of particles at the other end to take on their identity. Since then, physicists have used these ideas to actually teleport photons, atoms, and ions. And it's not too hard to imagine that molecules and perhaps even viruses could be teleported in the not-too-distant future.
But Masahiro Hotta at Tohoku University in Japan has come up with a much more exotic idea. Why not use the same quantum principles to teleport energy?
Today, building on a number of papers published in the last year, Hotta outlines his idea and its implications. The process of teleportation involves making a measurement on each one an entangled pair of particles. He points out that the measurement on the first particle injects quantum energy into the system. He then shows that by carefully choosing the measurement to do on the second particle, it is possible to extract the original energy.
All this is possible because there are always quantum fluctuations in the energy of any particle. The teleportation process allows you to inject quantum energy at one point in the universe and then exploit quantum energy fluctuations to extract it from another point. Of course, the energy of the system as whole is unchanged.
He gives the example of a string of entangled ions oscillating back and forth in an electric field trap, a bit like Newton's balls. Measuring the state of the first ion injects energy into the system in the form of a phonon, a quantum of oscillation. Hotta says that performing the right kind of measurement on the last ion extracts this energy. Since this can be done at the speed of light (in principle), the phonon doesn't travel across the intermediate ions so there is no heating of these ions. The energy has been transmitted without traveling across the intervening space. That's teleportation.
Just how we might exploit the ability to teleport energy isn't clear yet. Post your suggestions in the comments section if you have any.
But the really exciting stuff is the implications this has for the foundations of physics. Hotta says that his approach gives physicists a way of exploring the relationship between quantum information and quantum energy for the first time.
There is a growing sense that the properties of the universe are best described not by the laws that govern matter but by the laws that govern information. This appears to be true for the quantum world, is certainly true for special relativity, and is currently being explored for general relativity. Having a way to handle energy on the same footing may help to draw these diverse strands together.
Interesting stuff. There's no telling where this kind of thinking might lead.
Ref: arxiv.org/abs/1002.0200: Energy-Entanglement Relation for Quantum Energy Teleportation

 
 

Inching towards broadband quantum network realisation

http://www.eetindia.co.in/ART_8800632394_1800002_NT_10750973.HTM

Inching towards broadband quantum network realisation

Posted: 19 Jan 2011  Print Version  Bookmark and Share Subscribe
Researchers moved closer to realising broadband quantum networks with the demonstration of transferring quantum-bits (qubits) from entangled photons to solid-state crystalline memory devices.The researchers used a super-cooled crystal to demonstrate the reversible transfer of entangled qubits from a quantum network waveguide to the solid-state memory and back again.
The research group at the University of Calgary (Canada) collaborated with the University of Paderborn (Germany) in the reversible transfer of photon-photon entanglement into entanglement between a photon and the solid-state excitation of atoms. The rare-earth (thulium) doped lithium niobate waveguide made use of the photon-echo quantum memory protocol. Separately, another team of researchers at the University of Geneva (Switzerland) demonstrated a similar capability over a 50m fibre optical link, paving the way for quantum repeaters that could extend the ultra-secure communications of a quantum network to any distance.
The University of Calgary team demonstrated that their lithium niobate waveguides, which are already widely used for fibre optic communications, can handle signals from 5MHz to 5GHz, with a memory retention time of 7ns. Its broadband quantum memory used off-the-shelf lithium-niobate crystals, which needed to be supercooled to -270°C. Next, the group plans to create a real-time read-write channel using teleportation to transfer the qubits into and out of its solid-state memory.
"We have already demonstrated entanglement between a photon and the atoms of the crystal. Our next step will be to use interactions with a third photon to teleport its state into our solid-state memory by virtue of that entanglement," said University of Calgary professor Wolfgang Tittel at the Institute for Quantum Information Science. "This teleportation step will enable future quantum networks that provide ultra-secure long-distance communications."
For the future, besides perfecting teleportation as a means of transferring qubits to and from its quantum memories, the researchers are also planning to extend the memory retention time from 7ns towards a goal of 1s—a necessary condition for using repeaters to create large quantum networks.
R. Colin Johnson
EE Times

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Teleportation Takes Quantum Leap

http://news.nationalgeographic.com/news/2004/08/0818_040818_teleportation.html

Teleportation Takes Quantum Leap

Stefan Lovgren
for National Geographic News
April 18, 2004
It sounds like something out of Star Trek.
Austrian researchers have teleported photons (particles of light) across the Danube River in Vienna using technology that calls to mind Scotty beaming up Captain Kirk in the science fiction series.
"We were able to perform a quantum teleportation experiment for the first time ever outside a university laboratory," said Rupert Ursin, a researcher at the Institute for Experimental Physics at the University of Vienna in Austria.
The researchers read the "blueprints" of the photons they wanted to teleport. They then broke up the photons into smaller particles called quantum bits and sent these bits, along with the blueprints, through a fiber-optic cable in a sewage pipe under the river.
At the other end, replicas of the original photons were created. The original photons ceased to exist once the replicas were created.
Quantum teleportation may have progressed from science fiction to reality. But don't look for a Star Trek transporter anytime soon. This science has little to do with beaming people from one place to another.
Instead, scientists hope the technology could become crucial for quantum computing and quantum cryptology, areas that promise to make computing much faster and 100 percent secure.
The research is reported in this week's issue of the science journal Nature.
Disappearing Act
Teleportation involves dematerializing an object at one point and transferring the precise details of its configuration to another location, where the object is then reconstructed.
In quantum teleportation tiny units of computer information, called quantum bits, are transferred from one place to another. The technology is called teleportation because the information moved behaves more like an object than normal information.
"If you're writing an e-mail, you're sending [something] into a cable where it will travel and then come out at the other end," Ursin said. "But with quantum teleportation, you will not find the [full] information that you sent inside the cable. It's taken apart and put back together at the other end."

Teleportation was long considered impossible because it violates the so-called uncertainty principle of quantum mechanics. As the principle goes, the act of measuring a tiny particle destroys it. So theoretically, an exact replica of a particle can never be made.
But in 1993 scientists showed a way around the problem by using a complex concept known as entanglement, an area of physics that Albert Einstein referred to as "spooky action at a distance."
Since then, numerous experiments using photons have proved that quantum teleportation is possible. Scientists have teleported quantum bits along more than a mile (1.6 kilometers) of fiber-optic wire inside laboratories.
The science is not new, said Mark Kuzyk, a physics professor at Washington State University in Pullman. But this is the first time "researchers have demonstrated that teleportation works in the kinds of real-life conditions that are found in telecom applications."
No Eavesdropping
The most obvious practical application for quantum teleportation is in cryptology. Scientists say quantum physics can provide a completely secure method of communication between two distant correspondents. Sending photons entangled in a quantum state makes it impossible for an eavesdropper to intercept a message.
"There is no copy [of the information], so there is nothing to intercept," Ursin said.
The problem, for now, is that the quantum technology only works over limited distances. Physicists are now laying the groundwork for so-called quantum repeaters. Used in regular communications, these devices would allow messages to be transmitted around the world.
Commercial applications remain far off. "But this is really the step toward a real-world implementation of a long-distance quantum teleportation protocol," Ursin said.
So what are the chances of developing a transporter that can beam people from one location to another, Star Trek-style?
"Nothing we do will help us build Scotty's apparatus," Ursin said. "The reason is very simple: A human body contains too much information to scan and build all replicas."
For a human to be teleported, a machine would have to pinpoint and analyze the trillions and trillions of atoms that make up the human body. Only recently have scientists taken preliminary steps toward teleporting even a single, whole atom.
For more teleportation news, scroll down to bottom.
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Quantum Entanglement Could Stretch Across Time

http://www.wired.com/wiredscience/2011/01/timelike-entanglement/


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Quantum Entanglement Could Stretch Across Time


In the weird world of quantum physics, two linked particles can share a single fate, even when they’re miles apart.
Now, two physicists have mathematically described how this spooky effect, called entanglement, could also bind particles across time.
If their proposal can be tested, it could help process information in quantum computers and test physicists’ basic understanding of the universe.
“You can send your quantum state into the future without traversing the middle time,” said quantum physicist S. Jay Olson of Australia’s University of Queensland, lead author of the new study.
In ordinary entanglement, two particles (usually electrons or photons) are so intimately bound that they share one quantum state — spin, momentum and a host of other variables — between them. One particle always “knows” what the other is doing. Make a measurement on one member of an entangled pair, and the other changes immediately.
Physicists have figured out how to use entanglement to encrypt messages in uncrackable codes and build ultrafast computers. Entanglement can also help transmit encyclopedias’ worth of information from one place to another using only a few atoms, a protocol called quantum teleportation.
In a new paper posted on the physics preprint website arXiv.org, Olson and Queensland colleague Timothy Ralph perform the math to show how these same tricks can send quantum messages not only from place to place, but from the past to the future.

The equations involved defy simple mathematical explanation, but are intuitive: If it’s impossible to describe one particle without including the other, this logically extends to time as well as space.
“If you use our timelike entanglement, you find that [a quantum message] moves in time, while skipping over the intermediate points,” Olson said. “There really is no difference mathematically. Whatever you can do with ordinary entanglement, you should be able to do with timelike entanglement.”
Olson explained them with a Star Trek analogy. In one episode, “beam me up” teleportation expert Scotty is stranded on a distant planet with limited air supply. To survive, Scotty freezes himself in the transporter, awaiting rescue. When the Enterprise arrives decades later, Scotty steps out of the machine without having aged a day.
“It’s not time travel as you would ordinarily think of it, where it’s like, poof! You’re in the future,” Olson said. “But you get to skip the intervening time.”
According to quantum physicist Ivette Fuentes of the University of Nottingham, who saw Olson and Ralph present the work at a conference, it’s “one of the most interesting results” published in the last year.
“It stimulated our imaginations,” said Fuentes. “We know entanglement is a resource and we can do very interesting things with it, like quantum teleportation and quantum cryptography. We might be able to exploit this new entanglement to do interesting things.”
One such interesting thing could involve storing information in black holes, said physicist Jorma Louko, also of the University of Nottingham.
“They show that you can use the vacuum, that no-particle state, to store a lot of information in just a couple of atoms, and recover that info from other atoms later on,” Louko said. “The details of that have not been worked out, but I can foresee that the ideas that these authors use could be adapted to the black hole context.”
Entanglement in time could also be used to investigate as-yet-untested fundamentals of particle physics. In the 1970s, physicist Bill Unruh predicted that, if a spaceship accelerates through the empty space of a vacuum, particles should appear to pop out of the void. Particles carry energy, so they would be, in effect, a warm bath. Wave a thermometer outside, and it would record a positive temperature.
Called the Unruh effect, this is a solid prediction of quantum field theory. It’s never been observed, however, as a spaceship would have to accelerate at as-yet-unrealistic speeds to generate an effect large enough to be testable. But because timelike entanglement also involves particles emerging from vacuums, it could be used to conduct more convenient searches, relying on time rather than space.
Finding the Unruh effect would provide support for quantum field theory. But it might be even more exciting not to see the effect, Olson said.
“It would be more of a shocking result,” Olson said. “If you didn’t see it, something would be very wrong with our understanding.”
Image: flickr/Darren Tunnicliff
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It's All About You!

http://www.thedailybeast.com/blogs-and-stories/2009-09-24/its-all-about-you/

You're still reading Jay McInerney's Bright Lights, Big City 25 years later, says Dana Vachon, because you're just as self-absorbed as the culture it predicted.
Often this summer in social situations, while acting like myself, I’ve thought to amuse the people around me by observing Manhattan in the early '80s as an analog for the present day. “In both periods we have a charismatic president, huge deficits, the constant threat and chaotic thrill of sudden catastrophe from without,” is a sentence I’ve repeated so often that I must truly believe it. Now I realize that the early '80s is more than a parallel for present day, it is the era of origin for the notably American social scheme presently faltering: management of discontent through lifestyle fetishism built on widely available consumer credit. The Chinese are buying gold, the Treasury’s printing dollars, there is no more cash for clunkers. People are losing their homes, people are on food stamps, people are carrying assault rifles. Amid the charms of apocalypse, Bright Lights, Big City, Jay McInerney’s seminal novel about Manhattan in the early '80s, enters its 25th year of publication and significance as an early observation of Late America’s tendency toward the shattering of the self.
Patrick Bateman may be an anarcho-homicidal maniac, but unlike Carrie Bradshaw he is at least able to keep tabs on his many selves.
Many of the most impactful New York novels of the last quarter-century illustrate through their narratives an escalating crisis of identity. Sex and the City perhaps epitomized this by finding fullest form as a New York television show, premiering on HBO in 1998, the peak of Pax Clintonia. Sarah Jessica Parker played Candace Bushnell who everyone knew to be Carrie Bradshaw who narrated the true telenovela in voiceover like a breath of halothane, characterized by numbness masquerading as sweetness in advance of pain. A massive audience identified with the three parts, one heroine modern woman as scripted by a group of gay men who regarded her regarding herself in the first person, describing the varied material phenomena of bourgeois experience so that the first, second, and third people plural of the agora might lend meaning to her utterly fractured existence by reading about it in the newspaper. But really by watching it on television, where they found and were completely worked over by shiny reflections of their own imagined selves amid the shards of shattered identity. Lost to history is the true series pilot wherein Bradshaw, real name Velda Murkowski, charms her way out of Bellevue. At some point Murkowski breaks from her passage through schizoid spacetime to find that she has no money whatsoever, and, amid so many manic episodes, realizes her multiple and estranged selves have spent it all on shoes.
Bright Lights, Big City book cover Bright Lights, Big City. By Jay McInerney. 208 Pages. Vintage. $15. Go back to 1991 and take Bret Easton Ellis at his word—that the homicides and mutilations of American Psycho may have never happened save for as fantasies in its protagonist’s head—and you must conclude that, as a member of a species whose primary challenge remains basic survival, Ellis’ protagonist is a paragon of adjustment and mental hygiene compared to the mad women of Sex and the City. Patrick Bateman may be an anarcho-homicidal maniac, but unlike Carrie Bradshaw he is at least able to keep tabs on his many selves, knows exactly how many pairs of shoes they’re buying, how much they paid for them, and precisely how they feel when wearing them. Now, if some of Bateman’s selves should happen to fantasize about violently killing almost everyone he comes into contact with, well, as human motivations go that’s far more anthropologically natural and psychologically explainable than Samantha Cattrall foregoing the transmission of her own genetic material for the sake of a few more years of hard flesh, cocktails, and cock. American Psycho explores the intermediary stage in the confusion of self, a psychic space wherein the self may be breaking up, but is doing its best to remain friends who stay in touch. We know that Pat Bateman is not Pat Bateman, and, much to his credit, so does Pat Bateman.

Here I pause to note that all of these works arrived spaced seven years apart, and that this is the biblical length of plagues. And, further, that Jay McInerney’s 1984 publication of Bright Lights allows us excavation to an even earlier level of American self-confusion. The novel’s second-person narrative, which people found so powerfully affecting, cannot be dismissed as but a clever trick when seen in a broader context—as a visceral reaction to the early stage of a society where Don DeLillo’s J. A. K. Gladney tells us in 1985’s White Noise, “I am the false character that follows the name around.” McInerney and DeLillo knew early on what we have learned the hard way, that the Late American Republic of mass individualism is fully the contradiction it seems, less a total answer to human challenges then a psychic Madoff scheme whose false promise—that a better You is just another reinvention away—necessarily obliterates any meaningful or sustainable sense whatsoever of I. That at the center of American life is no longer a green light (Gatsby did get Daisy, for an afternoon) but rather a Mobius strip of hastily printed Obama bills, bubble-gum bound, through which You finds yourself sniffing the world.
At the end of Bright Lights we expect McInerney to bow at the altar of Scott Fitzgerald, to tell us You knows himself but that is all. Except that this doesn’t happen—You lives in a fresh second-person text mirroring a newborn second-person Republic bound for dizzying disasters and disjointments, and in neither setting is any such epiphany possible; when I doesn’t even know itself it can’t possibly realize it doesn’t know anything else, which is precisely what makes the nation’s present situation so precarious. With regards to You, You realizes, You exists on a purely need to know basis and at the end of the novel, You doesn’t need to know.
Bright Lights, Big City continues to move readers because McInerney saw what we all secretly suspected: that amid the orgy of American self I slips away to you, a sensory creature, sated by warm bread, your eyes transfixed by dawn’s rosy fingers, you eagerly awaits the new day and whatever you it brings; “We will have to go slowly,” is all that you can really know, in the end, “We will have to learn everything all over again.”
Plus: Check out Book Beast for more news on hot titles and authors and excerpts from the latest books.
Dana Vachon is a writer living in Manhattan.
For inquiries, please contact The Daily Beast at editorial@thedailybeast.com.


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