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Chinese Physicists Achieve Quantum Teleportation Over 60 Miles

Soulskill posted more than 2 years ago | from the just-keep-the-shields-up-and-you're-fine dept.

Network 216

MrSeb writes "Chinese physicists are reporting that they've successfully teleported photonic qubits (quantum bits) over a distance of 97 kilometers (60mi). This means that quantum data has been transmitted from one point to another, without passing through the intervening space. It's important to note that the Chinese researchers haven't actually made a photon disappear and reappear 97 kilometers away; rather, they've used quantum entanglement to recreate the same qubit in a new location, with the same subatomic properties as the original qubit. The previous record for transmitting entangled qubits was 16 kilometers, performed by another Chinese team back in 2010 — and perhaps most excitingly, the researchers seem confident that their system will scale up from 97km to distances capable of reaching orbital satellites, at which point we'll actually be able to build a global quantum network for all of our cryptographic needs."

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That's nothing (4, Funny)

crazyjj (2598719) | more than 2 years ago | (#39971097)

I hear the next step is transporting economic superpower status over 7,000 miles.

Re:That's nothing (2, Insightful)

Immostlyharmless (1311531) | more than 2 years ago | (#39971123)

Old News, it's already been done :P

Re:That's nothing (4, Interesting)

cpu6502 (1960974) | more than 2 years ago | (#39971257)

Reminds me of an Outer Limits episode.

They "transport" people through something similar to quantum entanglement that allows them to pass the data of Person #1 across several lightyears, and use that data to artificially create Person #1 at the new location. Of course that means they have two identical people, so they have to kill the original.

Re:That's nothing (2)

YodasEvilTwin (2014446) | more than 2 years ago | (#39971391)

I hold out hope that this will be possible in the very distant future, but there's a few giant problems to overcome: (1) Syncing trillions of atoms at the same time (2) Having the raw materials and movining them into place (3) Being able to determine the state of trillions of atoms at the same time.

Trillions? (4, Informative)

colinrichardday (768814) | more than 2 years ago | (#39971487)

If we have a 72-kg (158 lb.) person made mostly out of water, that's about 4,000 moles, or 2.4x10^27 molecules, which is about 7.2x10^27 atoms. The actual number might be different, but it's way more than a trillion.

Re:Trillions? (1)

Anonymous Coward | more than 2 years ago | (#39972151)

I wonder if the quantum states could be generalized for much of the mass. Does each water molecule need to be in the same state? Does each molecule of tissue need to be in the same quantum state?

It may be possible to narrow it down to just the central nervous system, and then possibly all the way down to just portions of the brain. Narrowing it down to just a couple hundred trillion atoms would be amazing.

While this would create a second (nearly) identical person at the other end, I don't see why you "have to" kill the original.

The next big obstacle is assembly. It's not like you can just throw all that data into a Makerbot.

Re:That's nothing (3)

crazyjj (2598719) | more than 2 years ago | (#39971403)

"Think Like a Dinosaur" [wikipedia.org] , based on the excellent short story by James Patrick Kelly. One of the best episodes of that series.

Re:That's nothing (-1, Offtopic)

cpu6502 (1960974) | more than 2 years ago | (#39971765)

Audio of the short story: http://www.sffaudio.com/?p=19883 [sffaudio.com]
Author's Website http://www.jimkelly.net/index.php?Itemid=50&id=35&option=com_content&task=view [jimkelly.net]

>>>Mitt Romney is going to punish the banks who stole your money--with less regulation and lower taxes. That'll teach 'em!

Barack Obama is already "punished" the banks who stole your money--with bailouts, jobs in his cabinet, and sweetheart deals that absolve them of mortgage fraud. That'll teach 'em!

Re:That's nothing (1)

Dr Herbert West (1357769) | more than 2 years ago | (#39972281)

I saw that episode, it was one of the better shows from the "new" series (not the black and white series from the 60s)

Re:That's nothing (2)

19thNervousBreakdown (768619) | more than 2 years ago | (#39971573)

If only we'd finished our ladder to Heaven first.

Re:That's nothing (2)

gbear711 (1321149) | more than 2 years ago | (#39971661)

Yeah, our grandchildren s confiscated cash wasn't good enough.

WE don't need this science trash (-1)

Anonymous Coward | more than 2 years ago | (#39971679)

More importantly, GOD will look after ALL our needs here in the US.

Quantum teleportation will only look after the "cryptographic needs" of the godless Chinese and other primitive science-believer cultures.

Re:WE don't need this science trash (0)

Anonymous Coward | more than 2 years ago | (#39972107)

Obvious troll is obvious.
 
But I would like to point out that this technology (or, the tech it will lead to) could be key to the claim of #1 superpower in the near future. We really ought to put some effort back into being intelligent.

Re:WE don't need this science trash (0, Funny)

Anonymous Coward | more than 2 years ago | (#39972307)

Obvious troll is obvious

Water is wet.

We really ought to put some effort back into being intelligent.

Some of us are intelligent. The rest believe in God.

Re:That's nothing (-1, Troll)

Jerry (6400) | more than 2 years ago | (#39972337)

The Chinese didn't do that, our Congress did when they passed NAFTA then opened the boarders so any remaining jobs could be farmed out to undocumented aliens willing to work for nothing and with no benefits. Either Congress did it deliberately to destroy the economic base of this country, or they were too stupid to realize what NAFTA would do to our economy. I believe it was the former.

Lord? (5, Funny)

i.r.id10t (595143) | more than 2 years ago | (#39971139)

Lord... Whats a qubit?

Re:Lord? (4, Funny)

Jose (15075) | more than 2 years ago | (#39971237)

Lord... Whats a qubit?

it is more of who than a what...Qubit is Q*Bert's Chinese cousin.

Re:Lord? (1)

rubycodez (864176) | more than 2 years ago | (#39971339)

Most Chinese cut their queue off these days

Re:Lord? (0)

Anonymous Coward | more than 2 years ago | (#39972087)

I bereive you'le thinking of Q*Belt. Faget.

Re:Lord? (2)

Anne_Nonymous (313852) | more than 2 years ago | (#39971301)

It's a new method for transmitting spam.

Re:Lord? (3, Funny)

osu-neko (2604) | more than 2 years ago | (#39971467)

Lord... Whats a qubit?

How long can you tread water? :p

Re:Lord? (1)

bigredradio (631970) | more than 2 years ago | (#39971651)

I was wondering if anyone else got the joke. Happened to listen to that album (vinyl) last weekend with my kids. Unfortunately, most of that skit was lost since I had to explain who Noah was. They have not been privy/subjected to Sunday school like I was.

Re:Lord? (1)

Beaker74 (453388) | more than 2 years ago | (#39971801)

Right!

Who is this, really? :) Love that album.

Re:Lord? (1)

_0xd0ad (1974778) | more than 2 years ago | (#39971837)

Bill Cosby [jr.co.il]

Re:Lord? (1)

Anonymous Coward | more than 2 years ago | (#39971541)

Let's see a cubit, I used to know what a cubit was.

Well don't worry about that just go out and collect all those animals by twos male and female and put them into the ark

Riiight.

Re:Lord? (0)

Anonymous Coward | more than 2 years ago | (#39971647)

jeez, I wanted to reply to this with the word "right..." which as you know the correct response - but ran afoul of the ascii art filter - wtf? killjoy.

Re:Lord? (0)

Anonymous Coward | more than 2 years ago | (#39971737)

Lets see a cubit...I used to know what a qubit was
Well don't worry about that Noah
When you get that done
Go out into the world and
Collect all of the animals in the world by twos
Male and female, and put them into the ark

Re:Lord? (5, Funny)

Qubit (100461) | more than 2 years ago | (#39971761)

Lord... Whats a qubit?

Here! I'm here... finally. I would have gotten here sooner if the Chinese hadn't been, you know, teleporting me around all morning.

*stretches*

Hmm... well that sucks. I think they made a mistake and put one of my quarks in upside down -- I feel strange all over now.

Re:Lord? (0)

Anonymous Coward | more than 2 years ago | (#39972673)

QBIT is a quantum bit.

One bit is just YES or NOT. A Quantum bit is MAY be YES or NOT (remember the schordinger paradox)

The final state is decided by a Quantum algorithm (a solution) So a group of QBITS is a Quantum message.
Bob and Alice, will shown the message only when the quantum cryptographic mechanism is enabled.

For free you can have higger speeds (Einstein-Podolsky-Rosen paradox) than normal light speed. This is called 'teleportation'
 

Satellites?? (1)

Anonymous Coward | more than 2 years ago | (#39971155)

Why would you involve satellites?

It is teleportation, so line-of-sight is not involved in this... Right?

Re:Satellites?? (5, Informative)

GameboyRMH (1153867) | more than 2 years ago | (#39971199)

You can't transmit meaningful information with quantum teleportation alone, you still need a classical channel that operates by conventional means unless you want to transmit uncontrollable random garbage.

Re:Satellites?? (5, Funny)

Anonymous Coward | more than 2 years ago | (#39971345)

unless you want to transmit uncontrollable random garbage.

So that means the satellite television providers will be all over this.

Re:Satellites?? (1)

AchilleTalon (540925) | more than 2 years ago | (#39971969)

As well as chinese restaurants.

Re:Satellites?? (1)

Beryllium Sphere(tm) (193358) | more than 2 years ago | (#39971631)

"Teleportation" would be for key creation and distribution.

Re:Satellites?? (1)

Anonymous Coward | more than 2 years ago | (#39971693)

You can't transmit meaningful information with quantum teleportation alone, you still need a classical channel that operates by CONVENTIONAL means unless you want to transmit uncontrollable random garbage.

why does it have to be "conventional"
Something conventional hundreds of years ago was lighting your house with fire or candles. now we have light bulbs.
At the time electricity was totally unconventional, now our society couldnt live without it.
Think outside the box, and it might just happen

Re:Satellites?? (1)

GameboyRMH (1153867) | more than 2 years ago | (#39971791)

And yet all those lighting sources and electricity all operate at exactly c, which our current understanding of physics says cannot be exceeded...unless you're a theoretical physicist you think inside this box.

Re:Satellites?? (1)

FrangoAssado (561740) | more than 2 years ago | (#39971861)

That's not really true. The real motive is explained in this other comment [slashdot.org] .

That said, I think that what you mean is (and this is true): to perform quantum teleportation, you still need a classical channel. But the reason for the satellites in this case is not that: the satellite is being used to send entangled photons (i.e., it's a quantum channel). The classical information could have been sent in any other way (over the Internet, for example), but to send entangled photons, there must be no measurements of the photon along the way.

Re:Satellites?? (4, Informative)

_0xd0ad (1974778) | more than 2 years ago | (#39971233)

The information contained in the qbit is transported from one entangled photon to another, but you first must get that entangled photon to the destination via more conventional means. They're doing that with a laser.

(Self-replying, I apologize) (5, Informative)

_0xd0ad (1974778) | more than 2 years ago | (#39971383)

Note that it's still limited by the speed of light. The key feature, however, is that it is secure: someone intercepting the photon can't copy or read its qbit state without breaking the quantum entanglement, or preventing it from reaching the destination. In either case, the receiver will immediately know that the channel has been broken. It then stops transmitting a response to the sender, and the sender perceives this as also a break in secure communications and stops transmitting. Both the sender and the receiver would then go into failure mode and send query/response polls periodically. When secure communications are re-established, they can resume transmitting data.

Re:Satellites?? (1)

rwven (663186) | more than 2 years ago | (#39971241)

Well, it's probably so spy photography could be securely transmitted from a satellite to earth. Other than that....excellent point. Could be transmitted straight "through" earth....except the part where it wouldn't actually be going THROUGH the earth.

Ender would be thrilled. (2)

rwven (663186) | more than 2 years ago | (#39971195)

So....how long until we have an Ansible?

Re:Ender would be thrilled. (2)

Githaron (2462596) | more than 2 years ago | (#39971265)

Just before Jane comes into existence due to the Hive Queen attempt to communicate with the humans.

Re:Ender would be thrilled. (1)

zAPPzAPP (1207370) | more than 2 years ago | (#39971353)

You did notice from the summary how this involves sending photons by laser?

Re:Ender would be thrilled. (1)

bolthole (122186) | more than 2 years ago | (#39971411)

If so then the summary of "without crossing the intervening distance" is a lie. The information was encoded and de-encoded for transit,but it still "travelled". No teleportation here, move along, move alone.

Re:Ender would be thrilled. (0)

Anonymous Coward | more than 2 years ago | (#39971683)

Alternatively, the information was simply *discovered* at both ends, and found to be in agreement when both points communicated subluminally afterwards.

This only works with a many-worlds interpretation of QM, though - there can't be a single hidden varible (says Bell's theorem).

Re:Ender would be thrilled. (5, Informative)

Baloroth (2370816) | more than 2 years ago | (#39971363)

This, and all other quantum "teleportation" and related entanglement phenomenon, do not allow for faster-than-light communication. The important thing to note is that the qubit is "teleported", not the photon itself: the photons are transmitted conventionally via some means (in this case, it looks like they did it through open air). Since the photons are entangled with a photon you retain, measuring one collapses the wave-function of the other and allows both parties to know what the state is simultaneously. The security ramifications are that any eavesdropper will collapse the wave-function before the receiver gets the photon, so he will not receive the photon in the same state as the receiver sent it.

You cannot, according to what we know of physics, use quantum entanglement to send information faster than light.

Re:Ender would be thrilled. (2)

rwven (663186) | more than 2 years ago | (#39971829)

Grrrr. Foiled again!

Re:Ender would be thrilled. (1)

FrangoAssado (561740) | more than 2 years ago | (#39972053)

It's actually worse than that. You could send the photons ahead of time (i.e., you could stock photons and use them to perform teleportation whenever you need it), but teleportation is still not "instantaneous".

The problem is that, to perform the teleportation, you must first measure the source, and then send the result of the measurement to the destination (that's just 2 bits of classical information). Given this information, the person in the destination chooses one of four measurements to perform in the corresponding destination photon, and then the teleportation is complete. Wikipedia [wikipedia.org] has a more detailed explanation, including the measurements performed.

Re:Ender would be thrilled. (1)

bdenton42 (1313735) | more than 2 years ago | (#39972623)

You cannot, according to what we know of physics, use quantum entanglement to send information faster than light.

But would it be faster sending information from one side of the Earth to the other than satellites or undersea fiber? If so financial institutions will be all over this.

Re:Ender would be thrilled. (1)

fadethepolice (689344) | more than 2 years ago | (#39972721)

You seem very sure of this. I am unsure. Since time is not a constant then almost anything is possible with regards to causality. Relative causality? http://arstechnica.com/science/2012/04/decision-to-entangle-effects-results-of-measurements-taken-beforehand/ [arstechnica.com] I would bet hard money you could run an experiment similar to this but instead send the information forward in time, faster than light. If you transported one of a pair of more stable molecules that were entangled then constantly manipulated there states wouldn't that information travel faster than light even though the particles themselves cannot travel from place to place faster than light? Also, if you took a stable wormhole and transported one end at the speed of light for an extended period of time. Then sent something through one side of the wormhole to another you could theoretically instantly skip the time betwen, allowing for either faster than light travel, or travel back in time.

Ansible? (0)

mspring (126862) | more than 2 years ago | (#39971215)

Is this finally the ansible [wikipedia.org] ?

Re:Ansible? (0)

Anonymous Coward | more than 2 years ago | (#39971405)

Sigh. What happened to the days when nerds would read science fiction without believing that someday it would all be real?

Re:Ansible? (1)

Eponymous Hero (2090636) | more than 2 years ago | (#39971845)

yeah like those guys who went to the moon. what a bunch of assholes!

Re:Ansible? (1)

rubycodez (864176) | more than 2 years ago | (#39971923)

Too much has become real from science fiction, and it's scary. One little ferinstance, Jules Verne had "electric bullets" that were mocked for over a century, of course you couldn't put enough charge into a projectile to make a foe fall "as if struck by a thunderbolt", right? http://electronics.howstuffworks.com/gadgets/other-gadgets/taser-shotgun-shell1.htm [howstuffworks.com]

Re:Ansible? (2)

spiffmastercow (1001386) | more than 2 years ago | (#39972015)

Sigh. What happened to the days when nerds would read science fiction without believing that someday it would all be real?

When was that? My dad still complains about not having a flying car or being able to take a flight to the moon.

Re:Ansible? (1)

Intrepid imaginaut (1970940) | more than 2 years ago | (#39972713)

or being able to take a flight to the moon.

Yes yes, working on it, give us about nine years.

Take THAT, Mr Mpaa Riaa! (2)

h00manist (800926) | more than 2 years ago | (#39971225)

Now we won't transfer our warez over any wires or IP numbers at all, and will just teleport the data all over the place.

How did they determine the distance? (1)

Sla$hPot (1189603) | more than 2 years ago | (#39971231)

How can you tell if it went 24,901.55 miles or 24,901.14 miles?
Does it travel in a straight line or around the earth or around the univers?
How do you define distance in the quantum world?

So it's replication (2)

HalAtWork (926717) | more than 2 years ago | (#39971235)

So it's replication, not teleportation?

Re:So it's replication (0)

Anonymous Coward | more than 2 years ago | (#39971285)

just like Star Trek transporters.

Re:So it's replication (3, Informative)

tstrunk (2562139) | more than 2 years ago | (#39971497)

So it's replication, not teleportation?

It's not replication, the quantum state of one photon is transfered from one photon to another.
Here's an easy explanation. http://www.youtube.com/watch?v=_qmSdC7aQpY [youtube.com]

Replication will never be possible as a quantum state cannot be copied: http://en.wikipedia.org/wiki/No-cloning_theorem [wikipedia.org]

Re:So it's replication (1)

interval1066 (668936) | more than 2 years ago | (#39971567)

Is making an exact copy, I mean EXACT, same quantum properties, same everything, mere replication? I think it goes beyond photocopying. Here's a question; so if its a good (the best) copy of something, does that we might be able to replicate objects ad infinitum? Could some mad asshole make a million Brittany Spears? I quake with fear...

Great Qubit Wall Of China (1)

localman57 (1340533) | more than 2 years ago | (#39971249)

In other news, another group of Chinese Scientists have announced that they have developed a method for filtering teleported qubits which contain information or ideas which are detrimental to the keeping of order of the society.

Sweet! (0)

Anonymous Coward | more than 2 years ago | (#39971253)

Instant Chinese Takeout!

This is not just China's Achievement (4, Funny)

l0ungeb0y (442022) | more than 2 years ago | (#39971279)

This is part of an international research effort, including schools like Carnegie-Mellon in the US. However, due to the lower costs of photonic qubits in China, it only makes sense to have the majority of experiments carried out over there.

So... (0)

Anonymous Coward | more than 2 years ago | (#39971355)

Basically we've developed quantom faxing? Is there still an annoying dial tone?

Re:So... (0)

Anonymous Coward | more than 2 years ago | (#39971415)

"quantum..." typo >.

Seriously (0)

Anonymous Coward | more than 2 years ago | (#39971375)

What the fuck is being talked about here?

Re:Seriously (1)

ColdWetDog (752185) | more than 2 years ago | (#39972499)

What the fuck is being talked about here?

If that's the entirety of discourse you bring to the site, you just might as well go back to 4chan with the rest of the invertebrates.

Turn in your nerd badges (1, Funny)

BitHive (578094) | more than 2 years ago | (#39971437)

Queue starry-eyed 500 posts about Ender's game by people whose idea of being a nerd is playing WoW while they wait for "the singularity", FTL communications, and REAL perpetual motion machines.

Chinese cryptography (1)

magarity (164372) | more than 2 years ago | (#39971439)

at which point we'll actually be able to build a global quantum network for all of our cryptographic needs."

If you think things are bad in Europe with the cameras everywhere and in the USA with the Patriot act and whatnot, you'll find out how good you have it when China is in charge of your cryptographic needs.

a butterfly flaps its wings in China... (1)

notgm (1069012) | more than 2 years ago | (#39971475)

and half a world away, another butterfly does too.

not nearly as exciting. boo, science!

CHINA'S cryptographic needs (1)

xxxJonBoyxxx (565205) | more than 2 years ago | (#39971557)

>> ...their system will scale up...to distances capable of reaching orbital satellites, at which point CHINA actually be able to build a global quantum network for all of CHINA'S cryptographic needs.

There - fixed that for ya'. Human rights - so 20th century.

Cool they learn how to copy.... (1)

nhat11 (1608159) | more than 2 years ago | (#39971579)

quantum style!

Provably secure (1)

mbone (558574) | more than 2 years ago | (#39971607)

There is a long, long history in cryptography of systems that were provably secure in principle proving not to be so in practice.

I'll believe any quantum crypto system is secure after attackers have been pounding on it for a decade or so.

Re:Provably secure (1)

ThatsMyNick (2004126) | more than 2 years ago | (#39971781)

This is not just another encryption scheme. What it is, is an encrypted stream, that cannot be intercepted without the knowledge of both sender and receiver. It is theoretically impossible for this to broken.

Re:Provably secure (1)

jpapon (1877296) | more than 2 years ago | (#39972055)

It is theoretically impossible for this to broken.

According to current theory, yes. I agree that it is impossible, as far as we understand things. If faster then light communication was found to be possible, then it seems that this would no longer be secure.

Re:Provably secure (0)

Anonymous Coward | more than 2 years ago | (#39971935)

I guess the Achilles' heel or quantum cryptography will be transmission losses. If they have to retransmit qubits, they'll be leaking information.

Hmmmmmm (1)

Pepebuho (167300) | more than 2 years ago | (#39971641)

Why build a plane when you can TELEPORT the bomb?

That is easy for the chinese. (0)

140Mandak262Jamuna (970587) | more than 2 years ago | (#39971649)

Going from point A to point B without going through any intervening points is quite easy for the chinese. They have gone from authoritarian regime to 1% - 99 % split oligarchy without going through the intervening democracy phase like America.

In Soviet China ... (0)

140Mandak262Jamuna (970587) | more than 2 years ago | (#39971685)

In Soviet China space moves through the particles. [I know I know it is weak and does not make sense. But if I bring the meme back from the dead someone might make a better one.]

Can Someone Explain At 5th Grade Level? (0)

Anonymous Coward | more than 2 years ago | (#39971709)

I've been completely unable to wrap my mind around quantum teleportation. I have a feeling it is due to the choice of labels that they are using. looking at the diagrams in the linked article, It seems remarkably like a beam of light rather than teleportation. But, they say that it is without passing through the intervening space. If that's the case, how is it targeted, received, measured? It seems dubious.

Can anyone explain what quantum teleporataion is at a 5th grade level? Perhaps using physical properties that the layman can relate to as metaphors?

Re:Can Someone Explain At 5th Grade Level? (2)

Eponymous Hero (2090636) | more than 2 years ago | (#39972377)

unfortunately this is beyond most 5th graders. any analogy for laymen will always fall short. analogies for those familiar with QM are tough enough as it is. but here's a classic bob and alice example: http://en.wikipedia.org/wiki/Quantum_teleportation#Motivation [wikipedia.org]

Scaling up (1)

jdavidb (449077) | more than 2 years ago | (#39971735)

and perhaps most excitingly, the researchers seem confident that their system will scale up from 97km to distances capable of reaching orbital satellites

Actually, what would be most exciting would be if they could scale up from qubits to about 86.6 kilograms of organized mass...

Why is 97 km different than 16 km? (1)

mcmonkey (96054) | more than 2 years ago | (#39971741)

Once you have the know-how and the hardware to do this, how is 97 km different from 16 km different from across the room?

Part of this is getting photons from point A to point B. But with fibre optics, couldn't they do 1000 or even 10,000 km with the same effort as 97?

Re:Why is 97 km different than 16 km? (1)

_0xd0ad (1974778) | more than 2 years ago | (#39971813)

The photons must remain in quantum entanglement while one photon is transmitted to the destination. A photon traveling through a glass fiber loses its quantum entanglement fairly rapidly.

China for all our "cryptographic needs"? (1)

Squidlips (1206004) | more than 2 years ago | (#39971847)

Sounds Great!

Security though overlooking the obvious - (1)

Darth Snowshoe (1434515) | more than 2 years ago | (#39971855)

I'm not sure I get why this method is thought to be any more secure than a conventional line-of-sight laser link.

It seems as though a line of sight laser that had conventionally encoded data in it would be pretty secure. Well, you'd have to get close to the laser light to observe it, and maybe use some super-fancy optics to couple to it and make a copy of the data. Highly unlikely but possible. But if the (assumed full-duplex) beams were obstructed, the link would be assumed compromised and sending could be halted.

In the case of the quantum version, it is said that the photons are entangled, so if an adversary inspected them, he'd "collapse the wave function" and it would be obvious to both the receiver and the sender, is that right? But, because its an optical beam, some amount of those entangled photons diverge, go astray, and are not ever received (at the receiver.) How does the sender distinguish between those that are legitimately received and those that go astray? Between those that are intercepted by an adversary and those that go astray? Could not then an adversary just choose to inspect those photons that weren't going to make it to the receiver anyway? And then, by 'collapsing the wavefunction' him or herself, be privy to (some portion of) the message?

Re:Security though overlooking the obvious - (1)

_0xd0ad (1974778) | more than 2 years ago | (#39971983)

Conventional lasers use a beam consisting of millions of photons, and some percentage of them have to reach the destination. In the quantum version, individual photons are transmitted, and all must reach the destination, or both transmitter and receiver will know that the secure link has been broken. Additionally, it's theoretically impossible to eavesdrop without either breaking the quantum entanglement, or blocking the photon (or both). Either way, both parties will detect it.

Re:Security though overlooking the obvious - (4, Insightful)

Darth Snowshoe (1434515) | more than 2 years ago | (#39972291)

Ah, but the abstract of the paper itself says "Over a 35-53 dB high-loss quantum channel, an average fidelity of 80.4(9) % is achieved for six distinct initial states." That sounds like a lossy channel to me. Plus, I simply don't believe it's possible to send a laser beam over X kilometers, including an atmosphere, and have them ALL reach their destination - it's a limitation of the medium.

Also, the Physics ArXiv blog post for this paper includes this;
"Inevitably photons get lost and entanglement is destroyed in such a process. Imperfections in the optics and air turbulence account for some of these losses but the biggest problem is beam widening (they did the experiment at an altitude of about 4000 metres). Since the beam spreads out as it travels, many of the photons simply miss the target altogether. "

and

"That's interesting because it's the same channel attenuation that you'd have to cope with when beaming photons to a satellite with, say, 20 centimetre optics orbiting at about 500 kilometres. "The successful quantum teleportation over such channel losses in combination with our high-frequency and high-accuracy [aiming] technique show the feasibility of satellite-based ultra-long-distance quantum teleportation," say Juan and co."

So it looks to me as though even the paper's author is admitting some "channel losses". The question I still have is, how is it possible to distinguish channel losses from adversarial interception of photons?

We've known the Pledge and Turn for awhile... (1)

rsmith84 (2540216) | more than 2 years ago | (#39971957)

So that makes this The Prestige... Anyone else get the vision of the amazing Tesla machine that Hugh Jackman commissioned to achieve "The Real Transported Man"?

Re:We've known the Pledge and Turn for awhile... (1)

Beardo the Bearded (321478) | more than 2 years ago | (#39972535)

No, we didn't.

Re:We've known the Pledge and Turn for awhile... (2)

Beardo the Bearded (321478) | more than 2 years ago | (#39972549)

Hey, Friday is my day to post.

Re:We've known the Pledge and Turn for awhile... (1)

Beardo the Bearded (321478) | more than 2 years ago | (#39972569)

No, you get Thursdays. My day is Friday.

Re:We've known the Pledge and Turn for awhile... (1)

Beardo the Bearded (321478) | more than 2 years ago | (#39972605)

Will the two of you SHUT UP?

Think Like a Dinosaur (0)

Anonymous Coward | more than 2 years ago | (#39971975)

Like every other Chinese mechanism, it actually only copies the subject matter on the other end.

But most importantly... (0)

Anonymous Coward | more than 2 years ago | (#39972051)

Is Gordon Freeman involved?

Who is this 'we' you refer to? (2)

PPH (736903) | more than 2 years ago | (#39972243)

at which point we'll actually be able to build a global quantum network for all of our cryptographic needs.

Are you a member of the Chinese Army?

Don't add significant figures (2, Insightful)

nedlohs (1335013) | more than 2 years ago | (#39972387)

It shows a complete lack of understanding of science.

And of course the actual distance will have been 100km which someone who does understand significant figures converted to 60 miles for Americans. Followed by a moron deciding to convert it to 97 km because they are scientifically illiterate.

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