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Science

Mathematical Breakthrough Sets Out Rules For More Effective Teleportation 162

Posted by Soulskill from the no-farther-away-than-40,000-km dept.
dsinc sends this news from the University of Cambridge: "For the last ten years, theoretical physicists have shown that the intense connections generated between particles as established in the quantum law of ‘entanglement’ may hold the key to eventual teleportation of information. Now, for the first time, researchers have worked out how entanglement could be 'recycled' to increase the efficiency of these connections. Published in the journal Physical Review Letters, the result could conceivably take us a step closer to sci-fi style teleportation in the future, although this research is purely theoretical in nature. ... Previous teleportation protocols have fallen into one of two camps, those that could only send scrambled information requiring correction by the receiver or, more recently, "port-based" teleportation that doesn't require a correction, but needs an impractical amount of entanglement – as each object sent would destroy the entangled state. Now, physicists from Cambridge, University College London, and the University of Gdansk have developed a protocol to provide an optimal solution in which the entangled state is 'recycled,' so that the gateway between particles holds for the teleportation of multiple objects. They have even devised a protocol in which multiple qubits can be teleported simultaneously, although the entangled state degrades proportionally to the amount of qubits sent in both cases."
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Mathematical Breakthrough Sets Out Rules For More Effective Teleportation More

Mathematical Breakthrough Sets Out Rules For More Effective Teleportation

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  • "More effective teleportation"!?!?!?! (Score:4, Insightful)

    by Anonymous Coward on Friday January 18, 2013 @05:52PM (#42630157)

    Bit optimistic, aren't we?

  • Where does extra energy go? (Score:4, Insightful)

    by pclminion ( 145572 ) on Friday January 18, 2013 @05:52PM (#42630161)
    Suppose I teleport an object from a height of 1000 feet to a height of 0 feet about sea level. There has been a loss of gravitational potential energy -- where does this energy end up? Conversely, if teleporting the object to a higher elevation, how is the gravitational PE imparted to the system?

    • Re: (Score:2, Informative)

      by Anonymous Coward

      As I understand the summary, this is dealing with quantum entanglement and the teleportation of information not matter...

      In star trek terms, think subspace radio, not transporter.

      • Re: (Score:2)

        by c0lo ( 1497653 )

        As I understand the summary, this is dealing with quantum entanglement and the teleportation of information not matter...

        In star trek terms, think subspace radio, not transporter.

        Uh, what a disappointment. Why can't you just flip that switch [xkcd.com]

    • Re: (Score:1)

      by Anonymous Coward

      Gravitation potential energy is not a change in the energy state of an object. A stationary object at 1000 ft has no energy. Once released, gravity imparts energy.

      • Stationary, relative to what?

        • Re: (Score:1)

          by msk ( 6205 )

          And how to deal with changes in angular velocity? Larry Niven had human-engineered teleportation limited to some fraction of the planetary circumference in order for equipment to deal with changes.

        • Stationary, relative to what?

          Well, obviously it would be relative to the source of gravity imparting this gravitational PE on the object. In our case, the surface of the Earth.

      • Re: (Score:3, Interesting)

        by Neil Jacklin ( 2818845 )
        Actually, the object does have _potential_ energy. I've wondered about OP's question before. I think the answer has to do with the fact that these "teleporters" don't transport matter in the conventional sense. Suppose you did have have a teleporter that could take an object and teleport it 100 ft up a hill. If you dropped the object, collected the potential energy (like in a waterwheel), and teleported it again, you shouldn't be able to violate conservation of energy or make a perpetual motion machine.

        • Re: (Score:1)

          by Anonymous Coward

          What the .... is the f icon next to your name?
          Does /. allow fecesbook logins now?
          There went the neighborhood! September again.

        • Actually, the object does have _potential_ energy. I've wondered about OP's question before. I think the answer has to do with the fact that these "teleporters" don't transport matter in the conventional sense.

          They don't transport anything at all. All the information is transferred at the speed of light or slower.

          • The basic, fundamental principle of quantum entanglement is "instantaneous sympathetic action at a distance"...with no regard for how long that distance is, therefore exceeding the speed of light for basically any measurable distance.

            • No information is exchanged though, information still moves slower than light.

            • I've never seen any evidence of "instantaneous sympathetic action at a distance" much less instantaneous transfer of information.

              Every experiment I've seen described -- it's entirely possible that I missed a lot -- was a variation on this:

              1. Some process generates two entangled photons, with unknown but complimentary polarization.
              2. Some aparatus, e.g. a beam splitter, causes one photon to go take one path and the other photon to take the other path. One photon goes to location A and other entangled photon

    • Re: (Score:3, Interesting)

      by Anonymous Coward

      The name " quantum teleportation [wikipedia.org]" is a bit misleading: no particles, mass or energy is teleported. The only thing "teleported" is a quantum state.

      What's remarkable about quantum teleportation is that you can transfer an exact quantum state from one place to another without sending any particle with that state along the way. That's remarkable because quantum states can't, in general, be copied (see the "no-cloning theorem [wikipedia.org]). When you perform a quantum teleportation, you must destroy the state of the originatin

      • The name "quantum teleportation [wikipedia.org]" is a bit misleading: no particles, mass or energy is teleported. The only thing "teleported" is a quantum state.

        Even that is not teleported. The energy is carried on the entangled particles. The quantum state is carried on the entangled particles.

      • Here's a classical analog to a quantum teleportation experiment:

        Dr. Roberts, in London, selects two cards from a deck. One is the Jack of Diamonds and the other is the Jack of Spades. He puts each of them in a sealed envelope along with a letter detailing his experiment. He instructs a graduate assistant, Miss Cunningham, to mail one to to Dr. Patel, in Mumbai and Dr. Eastwood, in Palo Alto. The accompanying letters identify all of the participants and the cards that were sent.

        Dr. Patel receives his let

    • Re:Where does extra energy go? (Score:4, Informative)

      by Charliemopps ( 1157495 ) on Friday January 18, 2013 @06:36PM (#42630505)

      Despite the authors attempt to make this sound like it has something to do with teleporting real world objects, it doesn't. Entanglement has to do with 2 particles sharing a state such as spin, and when that state changes in one entangled particle it also changes simultaneously regardless of distance or the speed of light in the other entangled particle. All of the laws of physics are observed. Information can not be passed faster than the speed of light. Matter can not move even at the speed of light, most of it no-where near the speed of light. You can not teleport an object from one place to another at all. There may be extended spacial dimensions that would allow us to do an end-run around distance, but keep in mind, if there are 4 or more spacial dimensions, we and all other matter already exist and are moving in those dimensions. There is very likely physical laws governing travel in them that would have the same effect that normal travel would. For example think if we were 2 dimensional creatures living on the surface of the earth and we suddenly discover the 3rd dimension and realize we could travel through the earth to reach china in half the time. While physically possible, there is that whole "Drilling through thousands of miles of solid rock" obstical that would make it a lot easier to just hop on a jet.

      Also, keep in mind that, to my knowledge and I just did a quick check and found nothing, humanity has never entangled anything other than photons/light. Which are technically both a wave and particle, but it's a hell of a long way off from entangling actual normal matter. Let me know when they entangle a Neutron and it'll be a big deal. Don't get me wrong, I think it's not beyond the laws of physics but we are very very very far away from true real world applications. The entanglement of photons can be explained via classical physics/optics, and doesn't need quantum theory to explain the effect. That doesn't mean it's not real, it just means you should take it with a grain of salt.

      This discovery makes experimentation easier. Teleporting yourself to work? Not so much.

      • You can not teleport an object from one place to another at all.

        But isn't the quantum state (which is what is being "teleported") exactly equivalent to a full description of the particle in question? Therefore isn't there absolutely no difference between doing this and what might be considered "classical" teleportation, i.e. the movement of a particle from point a to point b without travelling the intervening space?

        Also, keep in mind that, to my knowledge and I just did a quick check and found nothing, humanity has never entangled anything other than photons/light.

        How about entangling two macroscopic crystals, neutrons and all [popsci.com]?

        • But isn't the quantum state (which is what is being "teleported") exactly equivalent to a full description of the particle in question?

          Not normally. All the quantum experiments to date have only measured a single quantum property. For example, say you know the polarization of a photon. That doesn't mean you also know its phase, direction of travel, time of arrival and energy. Although other particles have not been entangled, the same would go for any other particle.

        • That's kind of a philosophical question isn't it? If they are 2 identical particals, are they the "Same" partical in any sense that matters? If they are, instead of teleporting and object don't you just have the object existing in 2 places at once? I think there's certainly a difference between classical teleportation and this, it just depends on your view of the universe. I think that there are plenty of 1950's SciFi novels that have addressed this conundrum without any successful resolution to the dilemma

      • 10 years ago, they were able to do the same trick with electrons.
          http://www.newscientist.com/article/dn1888-teleporting-larger-objects-becomes-real-possibility.html [newscientist.com]

        cheers

        • Bose and Home show mathematically that whenever one electron is detected in each path, they will be entangled.

          No they didn't. They did some math.

      • Re: (Score:1)

        by dfeifer ( 973821 )
        This would be interesting in the realm of communications though. If you were to isolate say 2-16 "bits" and have the equipment compact enough to read the state of these particles in a carryable device you would be looking at near real time communications no matter the distance. 2 bits you are looking at classic morse code one for a * and one for a -. 16 would be basic machine language. This would be great for spacecraft.

      • Re:Where does extra energy go? (Score:4, Informative)

        by stuckinarut ( 891702 ) on Friday January 18, 2013 @10:27PM (#42631879)
        Humanity has entangled stuff bigger than photons; The Biggest "Spooky" System Ever Seen: 4 Entangled Ions (Jun 2009) [discovermagazine.com] and Entangled diamonds , big enough for the eye to see (Dec 2011) [nature.com]. We haven't managed the information transportation part with anything other than photons though but we're doing well on distance; quantum key transmitted wirelessly 144km [aps.org].

      • Despite the authors attempt to make this sound like it has something to do with teleporting real world objects

        Which authors? I haven't seen any reference to object teleportation in the arXiv article (which contains the actual science). I also have seen no such mention in the text from the University of Cambridge. The only text making such connections is the Slashdot summary.

    • Re: (Score:2)

      by Zediker ( 885207 )
      More importantly, what actually allows them to change position in the first place. I'm not talking force here... But the actual physical change in position. Teleportation is a waste of time, Translocation however is more useful. Why move matter from point A to B when you can just redefine it at position B?

    • Speedy object goes in, speedy object comes out. -G.L.A.D.O.S.

      Where did you learn science?

    • Re: (Score:3, Interesting)

      by martin-boundary ( 547041 )
      Potential energy "exists" inside the gravitational field: It represents the total amount of work you have to do to traverse a certain path while being subjected to the effects of the field. For a conservative field like the gravitational one, the amount of work is independent of the actual path when the end points are fixed, and that's the reason, the only reason, why we can associate a single number, called potential energy, with any given height above ground level.

      In other words, potential energy is a m

      • Re: (Score:1)

        by jnm11 ( 1342437 )
        It's a fundemental violation of the laws of physics. Mass-energy can neither be created or destroyed. Nothing can "disappear" it can change state and move at the speed of light at best. Even the interactions of quantum mechanics and general relativity, e.g. Hawking radiation, conserve mass-energy and involve propogation of nothing faster than the speed of light. Quantum teleportation is no different.

    • I don't think you understand Gravitational Potential very well.

      The way you state it, you'd think a top shelf holding up an object would have to exert a larger force to counter gravity than the same object on a lower shelf due to that object's higher PEgrav which is due to it's greater distance from the gravity source(the Earth).

      Potential energy has not yet been imparted on the object, hence the word 'potential'. It is "how much energy this object could get solely from the force of gravity". The amount of en

    • Re: (Score:2)

      by tlhIngan ( 30335 )

      Suppose I teleport an object from a height of 1000 feet to a height of 0 feet about sea level. There has been a loss of gravitational potential energy -- where does this energy end up? Conversely, if teleporting the object to a higher elevation, how is the gravitational PE imparted to the system?

      Easy - it's absorbed/used by the transporter device.

      Lets say Kirk asks Scotty to beam him up. The Enterprise's transporter then takes Kirk's atoms and moves them to the Enterprise in orbit. Because transporter has t

    • Suppose I teleport an object from a height of 1000 feet to a height of 0 feet about sea level. There has been a loss of gravitational potential energy -- where does this energy end up? Conversely, if teleporting the object to a higher elevation, how is the gravitational PE imparted to the system?

      Although what they are talking about has to do with transporting data, not objects, your assumption is incorrect. If you transport the object from 1000 feet to 0 feet, something fills in the space that used to be occupied by the object and the object displaces what used to be occupying the space it now occupies. As such, the potential energy balances out, at least it would, if such a thing were possible in the first place.

    • The input energy in order to entangle the particles or to set a particular state maybe different depending on their relative position to each other.

  • Teleport Whales? (Score:1)

    by Anonymous Coward

    Maybe?

  • Well, maybe someday that would help to create something like USB but without physical medium between two connected points? Yeah, I know, "no information can be transferred through QE", but still, who knows how else can we sidestep "obvious physical limitations"? Not now, but in 20, 50, 100 years from now? I'd like to imagine our world with such technology widely adapted, and I just can't - possibilities are truly mind-boggling. Ah, I just like news like this - helps to get out of winter depression a little.
  • Instant teleportation of information according to STR violates causality. Is this a really serious science? Recycling state of quantum entanglement might be possible but as far as I know, quantum entangled particles don't "transport" information.

    • Re: (Score:3, Informative)

      by Tanuki64 ( 989726 )

      Instant teleportation of information according to STR violates causality. Is this a really serious science?

      For now it is math. Whether it is really relevant for real world physics is a totally different question.

    • Re: (Score:1)

      by rroman ( 2627559 )
      I will answer myself. They are talking about transporting quantum information or quantum state. Quantum information is _NOT_ the same as classical information. The summary is misleading in this way.

    • QE transmits the state of or change in the state of a particle. If you can't call that information, you're not thinking hard enough.

      That's like saying a binary 0 isn't information because it is, literally, nothing.

      • Re: (Score:1)

        by rroman ( 2627559 )
        It does not. QE binds particles in such a way, that when one particle is measured, the second is bound by this measurement. For example if you measure, that one particle has +1/2 spin, the second then has -1/2 spin. This is not transmission of information - you can't force one particle to have spin +1/2 and cause the second particle to have instantly -1/2 spin.

    • This is really serious science. And it doesn't allow to transmit information faster than light. You still need to send classical information to the other side. It's just that instead of correcting the state, the information tells the other side which of the many qubits is in the right state.

      As a simple (but not completely accurate) analogy, imagine you've generated a one-time pad, which is shared by Alice and Bob. This shared one-time pad represents the entangled state.

      The original teleportation scheme can

  • Is this going to help me untangle my Christmas tree lights?

    • Is this going to help me untangle my Christmas tree lights?

      No, this scheme is designed to preserve as much entanglement as possible.

  • Simple math ... (Score:3)

    by danwiz ( 538108 ) on Friday January 18, 2013 @10:08PM (#42631795)
    IF countBeingsInChamber > 1 THEN GOTO abort_transfer

  • Where's my fucking flying car?!

  • Hope they are aware of this before spending too much monies,
    http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=/netahtml/PTO/search-adv.html&r=1&f=G&l=50&d=PG01&p=1&S1=20060071122.PGNR.&OS=DN/20060071122&RS=DN/20060071122 [uspto.gov]

    -do note: this is akin to the person claiming barbie dolls he dug up were ancient relics.

  • We don't have inefficient teleportation let alone any teleportation. So take your mathematics and work it out with a pencil.

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