Posts Tagged ‘teleportation’
Researchers Succeed in Quantum Teleportation of Light Waves
Like Schrödinger's cat, teleported light is both dead and alive
No felines were harmed in the making of this experiment, which actually studied wave packets of light that existed in a state of quantum superposition, meaning they existed in two different phases simultaneously. This phenomenon is described in Erwin Schrodinger’s quantum mechanics thought experiment, in which a cat is simultaneously dead and alive, depending on the state of a subatomic particle.
In this experiment, researchers in Australia and Japan were able to transfer quantum information from one place to another without having to physically move it. It was destroyed in one place and instantly resurrected in another, “alive” again and unchanged. This is a major advance, as previous teleportation experiments were either very slow or caused some information to be lost.
The team employed a mind-boggling set of quantum manipulation techniques to achieve this, including squeezing, photon subtraction, entanglement and homodyne detection. The photo above depicts their device, nicknamed the Teleporter, in the lab of Akira Furusawa at the University of Tokyo.
The results pave the way for high-speed, high-fidelity transmission of information, according to Elanor Huntington, a professor at the University of New South Wales in Australia who was part of the study.
“If we can do this, we can do just about any form of communication needed for any quantum technology,” she said in a .
Instead of using ones and zeroes, quantum computers store data as qubits, which can represent one and zero simultaneously. This superposition enables the computers to solve multiple problems at once. The new, faster teleportation process means scientists can move blocks of this quantum information around within a computer or across a network, Huntington said.
Optics researcher Philippe Grangier at the Institut d’Optique in Palaiseau, France, said it was a major breakthrough.
“It shows that the controlled manipulation of quantum objects has progressed steadily and achieved objectives that seemed impossible just a few years ago,” he wrote in an that accompanies the study.
The results were published today in the journal Science.
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As if Quantum Teleportation Weren’t Spooky Enough, Physicists Propose ‘Time Teleportation’
Quantum entanglement is that “spooky action” (Einstein’s words, not ours) that links two particles such that a measurement on one immediately influences the state of the other, even if the two particles are separated by miles, or even light years. Entanglement defies the intuitive way we understand the universe to work (as does most of quantum mechanics). The idea of “time teleportation,” as described by S. Jay Olson and Timothy Ralph, doesn’t add clarity but it does introduce some interesting questions about the fundamentals of the universe.
In a sense, everyone and everything is time traveling, moving forward in time at a given rate. What Olson and Ralph propose is that it’s possible to take a shortcut into the future without being present in the interim. How? KFC explains:
The idea is that a detector acts on a qubit and then generates a classical message describing how this particle can be detected. Then, at some point in the future, another detector at the same position in space, receives this message and carries out the required measurement, thereby reconstructing the qubit.
But here’s the thing: said qubit doesn’t have to exist in the time between it’s initial detection and its reconstruction, though it is the exact same qubit. But there is a wrinkle, in that the initial creation of the qubit and its detection in the future must be symmetrical. "If the past detector was active at a quarter to 12:00, then the future detector must wait to become active at precisely a quarter past 12:00 in order to achieve entanglement," they say in their paper.
How does all this work? Admittedly, we’re not sure. But researchers have teleportation across space in the lab, so if time teleportation is truly as simple as space teleportation, we’ll likely be shown how it works sometime soon enough.
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Wikileaked Cables from Beijing Reveal China’s Pursuit of Fusion Power, Teleportation
One confidential diplomatic cable sent from the Beijing Embassy to Washington in February suggests China is doing big things at the small scale. For one, China is aggressively expanding its nuclear energy resources, with plans to open at least 70 nuclear plants in the next decade. More interestingly, the Chinese Academy of Sciences (CAS) is pouring research funding into its Institute of Plasma Physics (IPP) to conduct ongoing research into nuclear fusion.
Apparently China has been hard at work on its Experimental Advanced Superconducting Tokamak (EAST) reactor, which is designed to sustain a controlled fusion reaction that can go on indefinitely at high temperatures. In 2009, researchers apparently sustained a 18-million-degree reaction for 400 seconds, and a 180-million-degree reaction for 60 seconds. Their goal for 2010 was to sustain a 180-million-degree reaction for more than 400 seconds, though it’s unclear if they achieved that. Moreover, IPP is apparently conducting research on hybrid fission-fusion reactors, though details are slim.
Perhaps most interesting: China doubled the IPP budget in 2009 over 2008, and the diplomatic chatter suggests 2010’s budget saw a significant boost as well. Amid choppy economic waters, such funding bumps indicate a real commitment on China’s part to figure out the fusion energy puzzle.
China’s sci-tech ambitions don’t stop there. While the evidence is anecdotal, the embassy seems to think the Chinese are pulling ahead in fields like quantum communications and even teleportation. To quote one diplomat’s description of a trip to the University of Science and Technology of China (USTC) in Hefei: “A cursory walk through their labs seemed to indicate they had already succeeded in single-particle quantum teleportation and are now trying to conduct dual-particle quantum teleportation.”
Then there’s the Big Brother tech that we’ve come to expect from China. The same cable says the CAS’s Institute of Intelligent Machines (IIM) in Hefei has created a biometric system that identifies individuals through their pace and gait. “The device measure weight and two-dimensional sheer forces applied by a person’s foot during walking to create a uniquely identifiable biometrics profile,” the cable says, and can be installed covertly in a floor to surreptitiously collect biometric data.
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Working Tractor Beam Can Move Objects 5 Feet With Just Light
Using only light, Australian researchers say they are able to almost five feet through the air. It’s more than 100 times the distance achieved by existing optical “tweezers,” the researchers say.
Not quite a simple grabby tractor beam, the new system works by shining a hollow laser beam at an object and taking advantage of air-temperature differences to move it around.
Moving objects with powerful light is not new — researchers have long been using optical tweezers to pluck bacteria-sized particles and move them a few millimeters. The U.S. Secretary of Energy, Steven Chu, won his Nobel Prize for work with optical tweezers. But Andrei Rhode and colleagues at the Australian National University say their new laser device can move glass objects hundreds of times bigger than bacteria, and shove them a meter and a half (5 feet) or more. Rhode says the 1.5-meter limit was only because of the size of the table where he placed his lasers — he thinks he can move objects up to 10 meters, or about 30 feet.
It works by shining a hollow laser beam around small glass particles, as Inside Science explains. The air around the particle heats up, but the hollow center of the beam stays cool. The heated air molecules keep the object balanced in the dark center. But a small amount of light sneaks into the hollow, warming the air on one side of the object and nudging it along the length of the laser beam. Researchers can change the speed and direction of the glass object by changing the lasers’ brightness.
The system needs heated air or gas to work, so in its present incarnation it wouldn’t work in space — sorry, Star Wars fans. But it could be used for a variety of purposes on Earth, like biological research or movement of hazardous materials.
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Quantum Time Machine Lets You Travel to the Past Without Fear of Grandfather Paradox
Postselection is one of the notions that makes quantum computing simultaneously so exciting and perplexing; the idea that for a super-complex problem riddled with variables, you solve by letting the variables take any value at random and postselect for the one combination that makes the problem true. Put another way, rather than solving all the possible combinations to the problem one at a time, you run all possible combinations simultaneously and extract the set of variables that make the problem true.
Quantum mechanics seems to allow for such simultaneous computations of all possible outcomes theoretically, though actually making it happen is another issue altogether (such quantum computing would blow conventional computing methods out of the water). But combined with quantum teleportation – using quantum entanglement to reproduce a quantum state in space that previously existed at another point in space – MIT’s Seth Lloyd and colleagues say you can theoretically teleport a particle back in time.
This form of theoretical time travel solves two major problems associated with the feat. For one, it doesn’t require the bending of spacetime as most time travel theories do. Considering the conditions necessary to bend the fabric of spacetime might only exist in black holes, that’s a good thing. But further, due to the probabilistic laws of quantum mechanics, anything this method of time travel allows to happen already had a finite chance of happening anyhow. That means a particle can’t really go back and accidentally destroy itself.
Of course, the physicists didn’t demonstrate their theory in hopes of going back in time to ensure their parents end up getting married or some such. They’re hoping that by demonstrating these properties they will help push quantum thought toward a theory of gravity. But the idea of moving backward along the timeline without bending the fabric of the universe – or altering ones own future existence – is pretty amazing. If your interest is piqued, you can check out the entire paper .
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