Schizm
02-04-2010, 05:27 PM
http://www.technologyreview.com/blog/arxiv/24759/
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
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