Teleportation just got easier—but not for you, unfortunately

Aug 21, 2013 by Ben Buchler, The Conversation
Teleportation is still well and truly entrenched in science fiction, unless you’re a photon. Credit: Photon

Thanks to two studies published in Nature last Thursday, the chance of successful teleportation has considerably increased. Which is a good thing, right?

Whether or not you've ever been on a long-haul flight, you've probably fantasised about being able to magically disappear from one place and reappear in another. And a natural question for a physicist is whether there is any way to achieve this in practice.

In fact, something known as "quantum teleportation" became a reality in 1997. This first demonstration was for particles of light (photons). Since then, have also applied teleportation to other very small things, for example single atoms.

So when can we expect to just teleport ourselves to our chosen destination? You might want to sit down for this.

The first step to teleporting a person is measuring and recording the position, direction of motion and energy of every particle in the body, which would require more than will ever be available – much, much more.

In fact, a conservative estimate would mean you'd need about 1022 gigabytes (1 followed by 22 zeros) of hard drive space. That's a stack of hard drives about 20 light-years tall.

Proxima Centauri, the nearest star to Earth other than the sun, is around four light-years away.

Worse, we have no method to even make these measurements, let alone reconstruct a person based on the data. So we can forget about teleporting people.

Knowing enough – but not too much

What about something really simple – such as a single particle? How about an atom, or a photon? How can these be teleported?

The problem here was thought to be the Heisenberg uncertainty principle, a cornerstone of quantum mechanics that limits what you can know.

It might sound counter-intuitive, but if you try to measure the position of a single atom you will change its . If you find out exactly how fast it is moving, then you won't know where it is.

The problem is, if you want to teleport a particle, this is precisely the information you want to measure and transmit.

A physicist would call this information the "state" of the particle. If you're not allowed to measure the complete state of the particle, teleportation looks impossible.

So the key to teleportation is not knowing too much. As long as the measurements that you make do not reveal the position or velocity, then you have a loophole that allows you to circumvent the uncertainty principle.

What if you could disturb the particle before you measure it, so you never know its state, and then subtract off that disturbance at the other end to recreate the original state of the particle?

Credit: Wonderlane

This was the breakthrough realisation that American physicist Charles Bennett had in 1993. The key was to disturb the particle you want to teleport in a particular way. You can do this by using a pair of quantum-entangled particles.

These particles are linked to each other so that if you measure the state of one of the entangled pair, you learn about the state of the other half of the pair.

Alice and Bob

In the standard description of teleportation, Alice is teleporting something to Bob. Alice uses one of the entangled particles to measure the state of the input particle. She records what she measures and sends the information to Bob.

Bob can't tell what the state of the particle was, because the entanglement used in the measurement hides the true nature of the state.

What Bob can do, however, is use the information from Alice to modify the state of the other entangled particle. In this way he can recreate the exact state of the particle Alice originally measured.

Credit: Wikimedia Commons

This is how quantum teleportation works. Most photon experiments teleport over a metre or so inside a lab, although there has recently been a demonstration over 143km in the Canary Islands.

A sense of security

It turns out that quantum teleportation is not just a good party trick. The nature of the communication between Alice and Bob in this system is pretty interesting.

The information that Alice measures and sends to Bob cannot be used to recreate the input state without the other entangled particle. That means Eve the eavesdropper can't spy on Alice's measurement and get the information for herself.

The entangled pair is unique, so only Bob can recreate the original state. Immediately you have a technique for secure communication.

If you encode information in your , measure them with one part of an entangled state and then send the information to Bob, you have cryptography that is made strong by quantum physics. You really can't crack it by any means, unless you have the other part of the entangled pair.

Reasons to be cheerful

Teleportation has many other uses in systems.

These are proposed methods for building computers and communication networks that use as a core part of their functionality and have enormous potential to provide secure communications and high-speed computing.

The catch is that any time you want to move quantum information from one place to another in one of these systems, you can't just measure the information and send it to the next part of the process, since the measurement will destroy the information. Instead, you can teleport it.

Back to Nature

The two papers published together in this week's Nature show something very important.

Until now, teleporting photons of light using the method described above has been probabilistic, because you couldn't synchronise the arrival of the entangled photons with the arrival of the photon to be measured.

On the odd occasion when the photons aligned, the measurement would only work half the time. That means every time you try and teleport your information it will only work very occasionally – much less than 1% of the time.

If you have a lot of back-to-back-teleporting circuits in your quantum computer or quantum network, the chances of them all working together will become vanishingly small.

These two most recent experiments show deterministic in two different systems so that the process is no longer probabilistic. Instead it can, in principle, work every time a photon is ready to be teleported.

One of the new studies – by researchers from Japan and Germany – shows how it is possible to teleport photons of light that are in the infrared spectrum, just below the wavelength visible to the human eye.

The other experiment – by researchers in Switzerland and Australia – demonstrates teleportation of microwave photons with a frequencies between 4 and 7 GHz.

Neither system is production-ready, in the sense that they are both just proof of principle experiments. Although the teleportation is no longer probabilistic, it is still not 100% efficient – a 40% chance of success in the case of the infrared system and 25% in the case of the microwave system.

Still, this is a vast improvement on less than 1% that was previously possible with photons. Long-haul flights will continue for some time yet, but the new experiments represent a milestone on the long road to building a functional quantum information system.

Explore further: Quantum physics just got less complicated

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indio007
2 / 5 (12) Aug 21, 2013
I don't agree with this premise.
"The first step to teleporting a person is measuring and recording the position, direction of motion and energy of every particle in the body, which would require more data storage than will ever be available – much, much more."

Particles and virtual particles an be tunneled without knowing anything about them.
The above method is making an exact copy. That is not necessary. I would also think it is inadvisable.
Eirhead
1.8 / 5 (5) Aug 21, 2013
I think the first step to teleportation is creating 2 devices (transceivers) that momentarily impulse with an energy level so high that it is equalized by trading local spaces. I think you could make up the difference of a 100% complete fusion reaction by putting that energy into the plasma beam linking the 2 points.

2 simultaneous magnetic impulses and POOF you're there. No data need be recorded.
Wickedword
1 / 5 (6) Aug 21, 2013
Instead of moving a person's atoms to a new location via teleportation (which requires data measurements both the origin and destination "coordinates"), we should be working on a way to hold a person's atoms in stasis - in some sort of phased-state - in a **stationary spacial location**.... then let the Earth's rotation do the traveling for them.

Once the Earth has rotated to a pre-determined degree, the person is removed from phase and his atoms (which were never compressed or decoupled to begin with) are now several thousand miles from where they started.

Doesn't quite address interstellar teleportation, but hey....
DCM628
4.2 / 5 (5) Aug 21, 2013
Wickedword, regardless of if that would even be possible that is a terrible idea.

The Earth isn't just rotating. It's orbiting within the solar system, the solar system is moving within the galaxy, and the galaxy is moving within the universe. You couldn't just spin someone around the Earth that way, their "spatial location" would be nowhere near Earth even with a very short time frame.
sanslimite
1 / 5 (7) Aug 21, 2013
je pense que la téléportation est morte dans l'œuf, je me réfère à certains ovnis, il sufi propulser tourtes les molécule d'un engin dans sa masse ainsi que celles des occupants qui sont à l'intérieur, et il est possible d'avoir des accélérations comme si la masse n'existait pas, cela revient au même que de subir la pression atmosphérique qui est de 1 kg au cm² qui faits qu'en permanence nous avons plusieurs tonnes de pression sur le dos sans avoir la moindre gène.
sanslimite
1 / 5 (7) Aug 21, 2013
I think teleportation died in the egg, I refer to some UFOs, he sufi pies propel the molecule of a device in its mass as well as the occupants are inside, and it is possible to have acceleration as if the body did not exist, it is the same as undergoing the atmospheric pressure is 1 kg per cm ² which facts that we always have several tons of pressure on the back without any gene.
vacuum-mechanics
1.2 / 5 (10) Aug 21, 2013
What about something really simple – such as a single particle? How about an atom, or a photon? How can these be teleported?
The problem here was thought to be the Heisenberg uncertainty principle, a cornerstone of quantum mechanics that limits what you can know.

Understanding the working mechanism of the uncertainty principle may help.
These are proposed methods for building computers and communication networks that use quantum mechanics as a core part of their functionality and have enormous potential to provide secure communications and high-speed computing.

Unfortunately we still do not know the mechanism of the quantum mechanics, maybe this could help…
http://www.vacuum...19〈=en

megmaltese
1.4 / 5 (10) Aug 22, 2013
The first step to teleporting a person is measuring and recording the position, direction of motion and energy of every particle in the body, which would require more data storage than will ever be available – much, much more.


What about QUANTUM HARD DISKS?
The truth is that in the next 20 years we'll have a technological jump that nobody can imagine.
Our technological evolution, as you well know, is an incredible parabole.

Try to think to when people didn't think flight was possible. Then they didn't think space flight was possible. Then they thought landing on the Moon was impossible.

Turns out that everything that looked impossible was only due to our ignorance.
But we never learn this lesson, it seems.

I think teleportation will be available in this century, like many, many other things we can't believe are possible at the moment (FTL included).
megmaltese
1.4 / 5 (10) Aug 22, 2013
I don't agree with this premise.
"The first step to teleporting a person is measuring and recording the position, direction of motion and energy of every particle in the body, which would require more data storage than will ever be available – much, much more."

Particles and virtual particles an be tunneled without knowing anything about them.
The above method is making an exact copy. That is not necessary. I would also think it is inadvisable.


I agree with this, the real problem is the SPEED at which all that data would be read and written.
You would teleport a living being in the shortest time possible so to not have unwanted changes in the target copy.
So storing the data makes no sense.
But as I wrote in the other post: we can't imagine what technology will give us in the next half century. Quantum computing is at the door. With that, quantum memory will come too. And that will be a HUGE LEAP, almost unimaginable jump in computer technology.
megmaltese
1.8 / 5 (13) Aug 22, 2013
How poor is a person putting one star to my post without even explaining anything?
I dare you explain what's wrong in my posts by LOGIC.
megmaltese
1.8 / 5 (13) Aug 22, 2013
I hope you are less than 14 years old, stupid kid.
indio007
2.2 / 5 (10) Aug 22, 2013
How poor is a person putting one star to my post without even explaining anything?
I dare you explain what's wrong in my posts by LOGIC.


Don't sweat it, some people are dopes.

indio007
1 / 5 (7) Aug 22, 2013
The issue of teleportation seems to be obfuscated by words.

Example,
Quantum teleportation versus Quantum tunneling.

Quantum Tunneling is actually teleportation of the particle. The state of the particle does not need to be known. Quantum teleportation is remote manipulation of a distant state.

Tunneling has been observed at the micro and the macro. It has even been observed on the sea floor where the natural geography is conducive for the waves to tunnel.
Mechanical vibrations have been tunneled through vacuum. (thought to be impossible).

IMHO this is the way to go. It seems that any conserved quantity can be tunneled i.e. spin, angular momentum, orbital angular momentum ,polarization, linear momentum , single charge, etc.

trekgeek1
1 / 5 (1) Aug 23, 2013
The first step to teleporting a person is measuring and recording the position, direction of motion and energy of every particle in the body, which would require more data storage than will ever be available – much, much more.


I disagree. If a transporter scanner detects that a certain coordinate within my body contains a Hydrogen atom, I don't care about the angular momentum of the subatomic particles within. Just reconstruct me with a Hydrogen atom at that location with a precision of a tenth of an angstrom or so. No doubt all the Hydrogen atoms in my body are in different states at different times, but I'd bet they could be swapped without any issue. I think transporters would rely on the "good enough" principle. Not to mention the possibility of run length coding for data compression, i.e. place 100,000 Hydrogen atoms in a row. Maybe we can do more; like scan all the types of cells of a person with high precision and just say "place a quadrillion red blood cells there".
sitarek
1 / 5 (1) Aug 25, 2013
This kind of calculations or comparisons like how much hard drive space it would takes or how tall would it be etc. don't have much of the sense because we talking about distant future and when it times come those statements won't apply anymore. To achieve such goal like teleportation of something useful, a completely different approach and philosophy will be required.
Newbeak
3 / 5 (2) Aug 25, 2013
Please don't forget the idea of the Star Trek type transporter was originally conceived as a plot device to save money. Otherwise,every time a star ship was shown landing on a distant world,expensive sets would have had to be produced.Contrast that with showing the characters fading in and out ,which is far cheaper.See: http://en.wikiped..._Trek%29
Quantum teleportation definitely has a place in secure communications,but it will never be used to transmit matter,especially living matter.

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