Physicists Discover How To Teleport Energy 365
MikeChino writes "A physicist at Tohoku University in Japan has figured out how to teleport energy from one point in the universe to another. The technique is based upon prior research that shows it's possible to teleport information from one location to another, and involves making a measurement on each [of] an entangled pair of particles. The measurement on the first particle injects quantum energy into the system, and then by carefully choosing the measurement to do so on the second particle, it is possible to extract the original energy. Heady stuff, but essentially it means that you can inject energy at one point in the universe and extract it from somewhere else without changing the energy of the system as a whole."
Re:Consistent Histories? (Score:5, Informative)
I am not the guy to answer this, but I'm going to take a stab at it.
The article says that the prior research worked by transmitting the information separately, at the speed of light. So the idea here is apparently that the energy itself can be transmitted instantly, but you can't actually transmit information this way. Just energy.
Still, that rocks pretty hard.
Just a theoretical preprint, premature to plug it (Score:5, Informative)
Speaking as a Physicist, it seems the title should be " A physicist has posted a preprint in which he claims that "energy can be teleported"
(as opposed to beiing transmitted)." and someone has praised it in a blog post.
The astract says
"Protocols of quantum energy teleportation (QET), while retaining causality and local energy conservation, enable the transportation of energy from a subsystem of a many-body quantum system to a distant subsystem by local operations and classical communication through ground-state entanglement. We prove two energy-entanglement inequalities for a minimal QET model. These relations help us to gain a profound understanding of entanglement itself as a physical resource by relating entanglement to energy as an evident physical resource. "
note "classical communication" (i.e. a telephone call from one place to another) to tell the recipient what to do to extract the energy is needed.
Note that an arxiv post is an assertion by an author, prior to any refereeing. The are only minimal "fences" at arxiv.org to keep out the "Einstein was wrong, I am right" nuts.
Re:Consistent Histories? (Score:5, Informative)
So the idea here is apparently that the energy itself can be transmitted instantly, but you can't actually transmit information this way. Just energy.
No, energy can't be transmitted instantly. From the abstract:
Protocols of quantum energy teleportation (QET) (...) enable the transportation of energy from a subsystem of a many-body quantum system to a distant subsystem by local operations and classical communication through ground-state entanglement. We prove two energy-entanglement inequalities for a minimal QET model. [my emphasis]
So, you apparently still need the classical channel in order to know what measurement to perform in the receiving end, just like in good old quantum teleportation [wikipedia.org].
Re:Life Imitates Video Games (Score:3, Informative)
Yes, according to the lore they use entangled particles as a form of long range communication. EDI (Tricia Heifer of BSG fame) goes into some detail about how it works, which isn't that different from how the article here describes it.
Bioware deserve points for doing that kind of research into the game.
Its actually been around in Sci-Fi for quite some time. See Ansible [wikipedia.org], Orson Scott Card used it as the basis for Ender's Game and that whole series of books (though it got a bit extreme after the first one).
tm
Not faster than light, but still teleportation (Score:5, Informative)
The breakthrough the article is talking about is moving energy from one place to another "instantly" by means of performing the right pair of measurements on both end; but the communication between ends about what measurements to make still happens at light speed or less.
For example, say I have a bunch of particles here on Earth and my colleagues on Mars have another bunch of particles entangled with mine. Mars is at the moment ten light-minutes away from each. On my end, I perform a measurement on (i.e. I interact with) my particles in a way which raises their energy from X joules to Y joules; I then send a radio transmission (with said transmission using less than Y-X joules) to my colleagues on Mars giving them instructions for what measurements to make on their end, i.e. I transmit information, in normal ways, at the speed of light or less.
Ten minutes later, my colleagues on Mars get my message, perform the measurement, and BAM, the energy of their particles jumps up to Y joules. The most efficient classical alternative for transmitting that (Y-X) joules of energy would be to beam a signal of said energy between the two points, but that requires a clear line of sight between them, or some set of relays capable of carrying that signal, each of which adds inefficiency to the transmission. An even less efficient, even more classical method would be to take whatever the energy is stored in here on Earth and physically move it to its destination, which is both much slower and much less energy-efficient.
With this method, my colleagues could be buried deep underground in a sealed lab with no way of getting anything in or out except for a limited range of radio signals carried by equipment incapable of carrying high-power signals... and still I can "beam" them arbitrary amounts of energy straight into their lab just beaming energy into some particles in my lab and then telling them over the radio what to do in their lab to receive it.
Re:Consistent Histories? (Score:4, Informative)
Sorry to burst your bubble but you can't transmit information faster than light.
Period.
Re:Consistent Histories? (Score:5, Informative)
So the idea here is apparently that the energy itself can be transmitted instantly, but you can't actually transmit information this way. Just energy.
I'm pretty much pushing a rock up hill here, but some people enjoy pointless struggle.
Nothing is transmitted instantaneously. Not mass, not energy, not information. Nor, contrary to the article's false claims, has anyone ever teleported an electron, photon or atom, although people who don't understand quantum mechanics and physicists who would rather mislead the public to get positive mention in the press than do actual science will claim otherwise.
The only thing that gets "teleported" is the quantum state of an atom, electron or atom. As anyone who knows anything about quantum mechanics knows, the ontology of quantum states is a slippery beast, so talking about "teleporting" one as if it was ontologically identical to a brick or Captain Kirk is pretty questionable right off.
Teleporting a quantum state is completely different from teleporting a particle: if you could teleport a particle then the particle quantum numbers at the transmitter and receiver would change. In the case of quantum "teleportation" they do not. And the information is carried via entanglement using a perfectly ordinary beam of particles: if you were to stick your hand into the space through which information is being "teleported" the perfectly ordinary classical carrier particles would burn a hole through it.
In the case at hand, what is being discussed appears to be a fairly tame equivalent of quantum tunnelling, in which a spatially extended object like a string is excited into a higher energy state by an interaction at one end. There may be a small but finite chance that you can then de-excite the string from the other end pretty much instantaneously, because the excited state is a state of the whole spatially extended string, although the question of the speed at which that can occur is much debated.
Arguments over the "velocity" of the wavefunction under the barrier in quantum tunnelling have been going on since the early 1930's--there's a nice paper in Phys Rev from 1932 or thereabouts in which the authors did a pre-electronic-computer numerical solution to Schrodinger's equation to study the issue.
So to my mind, this is pretty ordinary, although a nice way of studying a much-debated and well-known curiosity of the quantum world, that has been marketed in a misleading and dishonest way to an ignorant press by the scientists in question, or which has been picked up the the ignorant press and distorted beyond all recognition despite the scientist's attempts at an honest and clear presentation.
Re:Consistent Histories? (Score:5, Informative)
There's an important subtlety here (Score:5, Informative)
From the abstract of the article:
Protocols of quantum energy teleportation (QET), while retaining causality and local energy conservation, enable the transportation of energy from a subsystem of a many-body quantum system to a distant subsystem by local operations and classical communication through ground-state entanglement.
There's an important line in there: while retaining [...] local energy conservation. What lies at the heart of the proposal is that the measurement devices add or remove energy from the system that they are measuring. The energy is in no way removed from one location and given to another, spatially distant, location. What happens, is that a measurement device at one location gains energy from the quantum system and, based on the outcome of that measurement, the measurement device at the second location can be configured to lose energy into the quantum system at that location.
The thing to take away is that no energy is lost or gained at either location. Instead, the measurement devices at each location gain or lose energy to compensate changes in the energy of the system. This proposal is in no way a method to teleport energy in the intuitive sense; the total energy of the quantum system and measurement device at each end is conserved. The notion that measuring a system changes the energy of the state is very fundamental in quantum mechanics and is well understood. Honestly, there's nothing particularly new about it and the paper doesn't appear to be written to be submitted to a major journal.
This reinforces my opinion that people need to stop submitting papers they find on arXiv, especially single-author papers.
Re:Consistent Histories? (Score:4, Informative)
Wikipedia's just described Slashdot in a nutshell.
Re:Consistent Histories? (Score:5, Informative)
Re:Consistent Histories? (Score:4, Informative)
They didn't claim FTL transmission anywhere. It's still "teleport" in a sense that you don't have any wires, beams etc over which to transmit energy. The information channel still has to exist, but the requirements to it are much lighter.
Re:Consistent Histories? (Score:1, Informative)
Yes, you could send any message that was on the schedule. If you wanted to improvise, you'd have to contact the other ship and tell them what pairs you were going to measure next, in what order. Having decided what the message is you need to transmit "instantaneously" and communicated what that message is going to be to the other ship, you can now do the tricky part of sending it via quantum entanglement. :)
Or you could just skip the quantum entanglement, and replace it with reading tea-leaves or some other mumbo-jumbo that can't transmit any information. Seeing as how you're just pretending to "send" messages instantaneously anyway.
It's frustrating, pop-sci articles *always* get this quantum entanglement thing wrong. Too many of those crazy Deepak Chopra books, perhaps. (I love how he wrote "Timeless Mind, Ageless Body" on how to stop aging by... wishful thinking,* apparently, and yet on all his later books he keeps looking older... and older... and older.. You'd think people would catch on.)
* Excuse me, that's QUANTUM PHYSICS-informed wishful thinking!
Re:Speaking of Consistent Histories... (Score:2, Informative)
The important part is this:
In the delayed choice quantum eraser discussed here, the pattern reappears even if the which-path information is erased shortly after, in time, the signal photons hit the primary detector. However, the interference pattern can only be seen retroactively once the idler photons have already been detected and the experimenter has obtained information about them, with the interference pattern being seen when the experimenter looks at particular subsets of signal photons that were matched with idlers that went to particular detectors.
The total pattern of signal photons at the primary detector never shows interference, [...]
You see, the past is not changed. What changes is that after we get the which-way information, we can identify subsets which show the interference patterns. There are no signals magically disappearing or moving after the fact. Basically the detectors D3 and D4 also convey information, just a different information than detectors 1 and 2: D3 and D4 reveal the information to which of the two overlayed interference patters the particular hit belongs. If the photon hits D1 or D2, that information is missing (just as the which-way information is missing if the photon hits D3 or D4). It still holds that you can only get one of the two types of information (complementarity), however saying that the past is modified is IMHO as reasonable as saying I'm modifying the past when I destroy an one-time pad previously used to encrypt a message, because as soon as I destroy it, the encrypted message disappears.
Re:Quantum "Teleportation" isn't teleportation at (Score:4, Informative)
1.) You have 2 Rubick's Cubes.
2.) You "entagle" them by making the faces of each Cube exactly identical to the other.
3.) You separate them physically into different geological locations.
4.) You "measure" Cube A by turning one of its sides.
5.) You call a handler at Cube B using a "common channel" (phone).
6.) Cube B is "measured" by having its identical face turned exactly replicating Step 4, per the instructions received by step 5.
7.) Repeat steps 4 through 6 until your heart is content.
8.) Bring the Cubes together, and marvel that their faces are still identical to each other.
Except that isn't how it works.
Here's a neat page [davidjarvis.ca] which goes to some lengths to explain why people are excited and mystified by this particular feature of reality.
It is a high school science level presentation, but frankly, that's my level and with something as peculiar as Quantum Entanglement, it helps to go through the steps as a refresher. If you want to skip ahead, then the goods can be found on this page. [davidjarvis.ca]
-FL
Re:Consistent Histories? (Score:3, Informative)
The cost of repairing a power line drops, yes. However, because overhead line are much more susceptible to taking damage from bad weather and storms, the total maintenance cost isn't necessarily lower. Especially if you have to pay compensation to customers for extended power failures.
Where I live, power lines have been replaced by buried cables during recent years, to a degree where almost the entire power grid is now below ground, because they are more reliable and less expensive in the long run.
Re:Life Imitates Video Games (Score:3, Informative)
>>If I recall, in Mass Effect 2 they used entangled particles for instantaneous long-distance transmission across the galaxy!
Yeah, one of the things I love about the Mass Effect series is that they actually have a consistent physics that would actually work if their core premise (Element Zero / Eezo) actually existed. Essentially, if you run an electric current through the Eezo, it reduces the mass of objects in the area based on the electric current, and the mass. When you reduce mass to zero, then you get to move at light speed for free. If you reduce it below zero, the theory goes, you get FTL speed.