Feeds

back to article Information teleportation goes large-scale

Quantum teleportation of information between quantum objects, like photons, is so well-understood that it’s almost routine. Now, an international physicists is claiming to have carried out the same trick in the macro universe. If the experiment can be replicated, it will be an impressive trick. The scientists, led by Jian-Wei …

COMMENTS

This topic is closed for new posts.
Bronze badge
Headmaster

AFAIK

"say they’ve teleported quantum state information between ensembles of 100 million rubidium atoms." does not equal "atoms". So while we could teleport quantum information... good luck using it to put something together by hand. :P

It's the difference between sending the information on your HDD, and the entire PC. The information on it's own is useful, but sending an entire PC would be the type of teleportation most would expect to be more useful.

Oh, that's also before we get into the problems with the differences between quantum information (qbits/superpositions) and "normal" (bits/collapses) information.

0
7
Silver badge
Facepalm

Re: AFAIK

----------------------------------------> you

-> the point

What this means is that instantaneous reception of distant data is now feasible. That means no lag in data transmission. It's not about building a teleporter.

Kids today.....

1
9
Bronze badge
Thumb Down

Re: "instantaneous reception of distant data is now feasible"

No, sorry, it's not. You forgot the 'quantum' bit. What they pass off as teleportation is they separate two things (without looking at either), then, when they look at the state of one, they can predict the state of the other with a high degree of accuracy.

It does not mean that they can force the state of one of the items and change the other, which you'd need to be able to do to send information. So no laws have been broken.

And if you're not entirely convinced by the idea of indeterminate unobserved quantum states in the first place, then they haven't actually achieved very much at all. Imagine rolling a die. Then, without looking at it, you slice it in half horizontally and post the bottom half to Australia. Now look at the face showing on your half and phone your mate in Australia and tell him what his half shows. Is he impressed? Probably not.

5
1
Paris Hilton

Ansible (Ender version)

Have they just built one?

0
0
Go

Re: Ansible (Ender version)

Depends.

How far apart can they separate the two devices? For that matter, how much information can they transmit & how fast?

Read Charles Stross' Singularity Sky or Iron Sunrise to see Quantum Communications at work...

0
0

Re: Ansible (Ender version)

If they have an array of 8 you have the beginnings of a binary transmitter, can probably squeeze in ECC too.

Just a shame that entanglement state doesn't last.

0
0
JDX
Gold badge

Re: Ansible (Ender version)

No it is not an ansible. I'm 90% sure that quantum-entanglement-teleportation doesn't violate the rule that you cannot transmit information faster than light. Can't remember the details though.

2
0

This post has been deleted by its author

Bronze badge
Boffin

Re: "quantum-entanglement-teleportation doesn't violate the rule"

No, it doesn't. Here's the macro-equivalent version of what quantum theory says is supposed to be happening.

You're given a pair of magic entangled dice. The rule is that when you roll them, one always comes up the opposite of the other. You roll a one, the other comes up six; two and five; three and four,etc. So you send one to your friend in Australia, then you both roll them together (you can even roll one before the other) and amazingly they still work together.

But here's the catch - if you look at them before they're rolled, the magic is broken. And you can only roll them once and never again. And if you try to make yours show a particular number, that also breaks the magic.

Now the quantum physicist will tell you that they're effectively rolling all the time, being all possible numbers at once, until you look at them. And he can demonstrate that by doing something else with some other dice as an example, but not on your pair as the test also stops them working. A cynic may suggest you've just been given a pair of dice where one is all ones and the other is all sixes, which is why you're not allowed to look, and the whole situation is as much practical use as a chocolate fireguard.

2
1

Re: "quantum-entanglement-teleportation doesn't violate the rule"

I dunno, at least you can eat a chocolate fire guard.

2
0
Silver badge
Coat

But can they teleport Schrödingers Cat?

Mine is the one with "Surely you're joking, mr. Feynman?" in the pocket

2
0
Anonymous Coward

I thought I was smart till I read this

I now feel like a moron in comparison to these guys. Using quantum entanglement to transfer data states at a distance on a macro scale. Mind boggling.

Next step - warp drives, holodecks and photon torpedos...

1
0
Silver badge
Mushroom

Re: I thought I was smart till I read this

Jet packs, JET PACKS, JET PACKS!! Why do people always forget about the *'#?ing jet packs!

Priority. Number. ONE.

Ahem. I think I need to get our more.

0
0
Silver badge
Megaphone

Re: I thought I was smart till I read this

Jet packs and flying cars!

1
0
Pirate

Re: I thought I was smart till I read this

Oh come on people!

Jet Packs, Flying cars and protein pills!

Doesn't anyone remember Major Tom?

Yes, I AM the real Ground Control...

0
0
Silver badge
Stop

Science versus Science Fiction

The problem with conflating science and science fiction is that the latter rarely accounts for quantum properties. Quantum teleportation works, but classical teleportation does not. So you can teleport atomic states, but you get no instantaneous information transfer out of it. In a nutshell, you must compare the two quantum measurements to convert the quantum to classical information. So you still have to make that expensive light-speed call.

Holodecks and photon torpedos, of course, are much easier.

0
0
WTF?

I know I've misunderstood this, but....

To summarise: Scientists go "Woo Hoo!" at sending information via photon over fiber optic.

Honest question - what is the signifcance of the breakthrough here?

0
0
Silver badge

what is the signifcance of the breakthrough here

State goes from point A to point Z without passing through points B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X and (pauses for breath) Y.

Which in theory means that you can build a brick wall between the two assemblies and still see these results.

1
2

Re: what is the signifcance of the breakthrough here

> Which in theory means that you can build a brick wall between the two assemblies and still see these results.

As long as there is a hole in the wall for the fibre optic.

1
0

This post has been deleted by its author

Silver badge
Joke

So Star Trek should have been like this...

"I'm sorry Captain, but Spock didn't make it - the transporter only works 88% of the time. I'm afraid I cannee break the laws of physics.

"Oh, and you've popped back, too - because it only lasts 129µs....

"Still, good luck with the Klingons; I'm outa here!"

0
1
JDX
Gold badge

Confused

I thought quantum entanglement was totally unaffected by removing the entangled entities to any distance. The 'teleportation' is not done by photons but quantum 'magic' between the entangled objects... so I don't see the relevance of the optical cable or how long it is.

2
1
Anonymous Coward

Re: Confused

Quantum teleportation is the transfer of the quantum state of one entity to another, using a pair of entangled entities to achieve the transfer. However, the process still requires some classical information to be sent. For example, a two-state quantum system, such as a qubit, when teleported, will leave the target qubit in one of four states. This means that two bits of classical information are required to tell you which of the four states it is in, and consequently what you need to do to transform the state into the original state that was teleported. Note that the state of the original qubit is lost in the process, as it is measured (to produce one of the classical bits of information that is then required to be sent over a classical channel).

0
0
Silver badge
Pint

Re: Confused

> I thought quantum entanglement was totally unaffected by removing the entangled entities to any distance.

That, truly, is still an open question that has to be solved experimentally. It is commonly assumed that entanglement does not break down over large distances or large differences in time because the mathematics currently used to describe what happens say "no, it's just a state as any other". But is that really so? No-one knows for real.

0
0
Silver badge

Quantum entanglement totally unaffected by distance

Quantum information is lost by decoherence. This is not a matter of distance, but of interaction with the rest of the universe. If you can keep your entangled particles well-isolated from any external forces and photons, then the distance or the brick wall does not matter. If your particles ever sees the brick wall (photons!), then the entanglement is toast.

There is a property called 'coherence lifetime' that tells you when you lost coherence (drop to 1/2.718).

0
0
Bronze badge
Meh

Count me in

Amongst those who feel let down once they read there's a bit of wire between these two things, Teleportation is the wrong word for this, it conjures images of well, conjuring stuff out of thin air, like Kirk for instance.

This seems more like (useful yet boring), quantum cloning over a phone line.

0
0

Re: Count me in

IIRC quantum teleportation has also been done over 140km+ of free space now. But that's a different part of the overall system, you wouldn't want to research everything at once. That's why they used the fibre - although how they can know that the entanglement effect is travelling 150m through the fibre rather than 0.5m across the desk is a tricky question.

We know how to warm things up by rubbing sticks together, but in the chemistry lab we still use Bunsen burners...

It still isn't _actual_ teleportation though. Boo.

0
0
Anonymous Coward

Re: Count me in

You wouldn't quantum clone a car.

0
0
Anonymous Coward

Re: Count me in

This is definitely not quantum cloning, as that is impossible.

0
0
Silver badge

Re: Count me in

You wouldn't quantum download a cat!

0
0
Bronze badge
Childcatcher

Re: Count me in

You wouldn't quantum download a cat!

Would if I could.

0
0
Silver badge
Happy

Re: Count me in

That's about the single occasion where copying does become stealing.

0
0
Silver badge
Facepalm

Holy stuff, the comments at Phys.org reach YouTube level of stupidity.

"Don't accept that relativity anyway..makes no sense, and as an engineer was taught to reject nonsense answers no matter who said them."

I sure hope that guy does not engineer any machines I need.

1
0
Bronze badge

To be fair, people can be remarkably competent in one area while being remarkably stupid in another. One might even conjecture this is true of most or even all people.

Still, remarks like that do give one pause.

0
0
This topic is closed for new posts.