The scary thing is that I use quantum effects (specifically, Förster resonance energy transfer) at work almost every day. I have a reputation for knowing how this stuff works, at least as far as biologists go. Yet I have only the vaguest idea what is going on in this paper from today’s issue of Nature.
Quantum teleportation over 143 kilometres using active feed-forward
…[W]e report [quantum teleportation of independent qubits over a free-space link whose attenuation corresponds to the path between a satellite and a ground station], using active feed-forward in real time. The experiment uses two free-space optical links, quantum and classical, over 143 kilometres between the two Canary Islands of La Palma and Tenerife. To achieve this, we combine advanced techniques involving a frequency-uncorrelated polarization-entangled photon pair source, ultra-low-noise single-photon detectors and entanglement-assisted clock synchronization. The average teleported state fidelity is well beyond the classical limit9 of two-thirds. Furthermore, we confirm the quality of the quantum teleportation procedure without feed-forward by complete quantum process tomography. Our experiment verifies the maturity and applicability of such technologies in real-world scenarios, in particular for future satellite-based quantum teleportation.
If anyone can explain this in language that regular people can grok, I promise to add it as an update. Bonus points if you address which technologies from Star Trek this quantum telewhatzis can and cannot make possible.
Speaking of which, I was bummed to hear that warp drive might possibly work, but it would take almost all the energy in the universe, you can’t stop and it would obliterate everything in your path.
***Update***
Thanks, Visceral.
It means you can “entangle” two subatomic particles in such a way that if you do something to one of them – like knock it with another subatomic particle – its entangled partner will instantaneously behave as though you’d knocked it instead. What gets teleported is the quantum state, not the particle itself; there were always two of them. It gets called teleportation because there is no obvious link between the particles – other than quantum entanglement – that would allow quantum effects to be transmitted between them, especially if the transmission is effectively faster than light.
Unfortunately, this phenomenon would be useless for beaming people and things around. It would allow for theoretically instantaneous communication across vast distances, even light years.
Gin & Tonic
OK, but is there any downside?
Another Halocene Human
Obliterate everything in your path? Sounds about right.
The press release sounds more tech company than scientist, so I’m a little skeptical. They seem to be talking about photon entanglement which is not teleportation, no matter what they say.
Another Halocene Human
@Another Halocene Human: Think “ansible” if you’re a scifi fan, but with only one bit.
Villago Delenda Est
All you need to know is that it will get our heroes into the action well before the commercial break.
General Stuck
Reminds me of when I was 10 or so, and riding in my older cousins Buick of some sort that was built like a tank with a souped up engine. One day the breaks went mushy and we nearly wrecked. I asked him why didn’t we stop, and he told me this baby wasn’t meant to stop.
rlrr
In theory, it should be possible to quantum teleport a large object, but the process would destroy the original and create a duplicate at the destination. I’ll leave it up for discussion whether it would be desirable for a human to go through the process…
NorthLeft12
I think maybe you should ask this guy…..
dekerivers.files.wordpress.com/2012/05/sheldon-cooper.jpg
Sea Subb
@Another Halocene Human:
But this isn’t faster than light, is it?
El Cid
Here’s a good walk-through of the experiment.
Culture of Truth
The dangers of warp drive are a liberal hoax.
Todd
I’ve said it forever – we are locked into the immediate vicinity of our gravity well by relativity, and had better take care of what resources we have available.
Amir Khalid
@rlrr:
Remember what happened in that Star Trek movie, when the process got interrupted partway through and a Starfleet officer arrived at the destination transporter as a pile of Vulcanburger? Shudder.
MariedeGournay
@Gin & Tonic: Ha!
cervantes
Sadly, it isn’t really teleportation and it is not possible to send any information, or mass/energy by this means. You can only tell after the fact that the particles demonstrated quantum entanglement. I.e., you can’t decide “I’m going to send a 1 or a 0 to the destination.”
giltay
I believe the actual script for this episode reads, “[W]e report [tech over a tech whose tech techs a tech], using tech in tech,” and Spiner or Burton just ad libbed it.
Culture of Truth
Could we send a device to Mars which would enable us to teleport a person there? Because even it would be risky people would volunteer for it, certainly.
Sly
@rlrr:
No one cares about the man in the box… the man who disappears.
Nick
@Another Halocene Human:
“They seem to be talking about photon entanglement which is not teleportation, no matter what they say.”
Uh, yes, it is. It is necessary for two parties to share an entangled two-qubit quantum state in order to do quantum teleportation, and photons are a really easy way to do it. What exactly is your definition of teleportation?
Credentials: graduate student in quantum information theory
rlrr
@Culture of Truth:
In principle, maybe, but the computational problem is likely intractable for an object with any complexity.
Villago Delenda Est
@Nick:
Are you sure you’re not a Trek tech consultant? Because this sounds a lot like a Geordi LaForge, Miles O’Brien, or B’Elanna Torres bit of dialog.
The Red Pen
Fixed.
rlrr
@Nick:
Also, what I’m discussing is not quantum entanglement. It’s measuring the quantum state of every particle in an object (which would necessarily destroy it) and transmitting the data to a remote device which could recreate the quantum states of all the particles.
scav
All I can think is that if ever two parties did share an entangled two-qubit quantum state, that’d be one hell of a messy divorce.
catclub
The obliterate everything in your path bit, makes it sound like the front of the spacecraft doing Warp speed might be subject to a bit of ablation – like many lightyears worth of space dust adding up to total destruction of the spacecraft.
But I am not a rocket scientist, so what would I know.
quannlace
But that’s only if you let the matter and anti-matter mix ! ;-)
Face
Of course, 2 absolutely gorgeous islands was the only place that this experiment could be run. Sucks to be a well-funded scientist.
Post-doc applications to this guy’s lab just quadrupled.
flukebucket
It breaks my heart that I can’t even begin to understand this stuff.
But spooky action from a distance is how I like to describe the causes of any and all of my fuck ups.
Punchy
Clearly designed and built by a Republican.
gnomedad
@Culture of Truth:
Warp, baby, warp!
Roger Moore
@Todd:
We’re fairly effectively locked into our gravity well by gravity. Unless/until we get a usable space elevator, just getting into LEO is going to be the biggest stumbling block for seriously getting into space, not anything complex like relativity.
Nick
@rlrr:
You actually can’t do that at all (if I’m understanding your strategy correctly), as it would violate the no-cloning theorem. Quantum teleportation is actually a very subtle process, and it’s physically impossible to do what seems like the obvious thing.
rlrr
@Punchy:
But Republicans don’t believe in science…
Maude
The Fly.
rlrr
@Nick:
Possibly, but it’s not really cloning since the original no longer exists…
jayackroyd
Spooky!
artem1s
fabric that disintegrates if and only if being worn by JTK during a fight.
windycitynerd.files.wordpress.com/2012/02/captain-kirk-ripped-shirt3.jpg
jayackroyd
@rlrr:
Works on Vulcans! David Gerrold (“The Trouble with Tribbles”) wrote a funny book on the stupidities of the original Star Trek. The funniest, to my mind, is what the hell did they need that transporter room for?
Ed Drone
@Amir Khalid:
Larry Niven has written several articles (or talks) about the ramifications of teleportation, showing the upside and down of it. For instance, conservation of motion is never mentioned in stories, but is real. Teleporting from NY to Capetown, for instance, would result in you being splattered on the side of the tele-booth on arrival, since those two spots are moving at differing speeds. Pole-to-equator trips would require the largest shock-absorber you could envision.
And the excess energy from the change would likely result in thermal differences, too. You’d arrive in a hot and heavy hurry.
He even worked out the societal effects. If the process is expensive, it’s used for interplanetary travel; if it’s middling expensive, it’s for intercontinental travel; if it’s trivially cheap, autos and their ilk disappear, and you use it to go cross-town. The effects on your society are enormous.
And what if someone steals the signal? Is that kidnapping? Or stores the signal, allowing the recreation of an individual at some time in the future, unchanged from their original self. Cloning? Easy!
Just some of the ideas Niven expounded.
Ed
rlrr
@jayackroyd:
what the hell did they need that transporter room for?
So it can be redressed and serve as the ship’s chapel.
joes527
@rlrr: reocities.com/SoHo/cafe/5947/teleport.html
Judas Escargot, Acerbic Prophet of the Mighty Potato God
@Todd:
It’s a big solar system. Enough to keep us busy for a few thousands of years, anyway.
I can’t speak to the physics, but I can speak to the security/encryption aspects.
Despite what articles like this imply, it’s (generally not considered) true that quantum encryption would be unbreakable. Rather, the recipient would know for certain whether or not anyone en route had intercepted the message, either to eavesdrop or to corrupt it (because the snooper would unavoidably change the information state, and thereby be detected).
Not that that wouldn’t be extremely useful. But you don’t get “unbreakable encryption” from this.
Yutsano
@jayackroyd: They actually have a Trekkie explanation (or justification if you will) for the transporter room. According to Trek lore, it’s easier to transport from one fixed energy source than from site to site. I didn’t say it was a GOOD one. :)
The Other Chuck
@Ed Drone: There was some book I read whose name I can’t remember, in which virtually the entire population has developed the ability to teleport themselves. Doors have disappeared, as have roads and walkways, which are now only inhabited by wretched deficients who never developed the ability, or by hipsters affecting this quaint means of locomotion. Flash mobs have become a real problem (I think the book may have even coined the term). Since people can only teleport to a place they have been or can otherwise determine a path to, the wealthy have taken to burying their homes in byzantine mazes through which visitors are led blindfolded.
Anyone remember the name?
The Red Pen
@Culture of Truth:
There was an episode of Star Trek:The Next Generation where they discover that traveling faster than Warp 5 was bad for the subspace ecology, so they promise the subspace aliens that they’ll cut down.
Never heard much about it after that episode. Perhaps some emails were discovered by E’Rick Son of E’Rick that exposed the whole thing as a secret Vulcan plot or something.
Plus, just because Spock’s mother is human doesn’t mean he can be president.
Dennis SGMM
Looks like to me that the researchers quoted are, or think that they are, using quantum entanglement to transmit binary information. Their use of the word “teleportation” suggests that they are even phonier than Mitt Romney.
The Red Pen
@The Other Chuck:
New item on my “when I win the lottery” list.
The Other Chuck
@The Red Pen: They made a couple references to it afterward, mentioning that they needed permission from Starfleet to exceed the warp speed limit.
Dennis SGMM
@The Other Chuck:
Not quite the book that you are thinking of. In Alfred Bester’s ever-commendable The Stars My Destination people were capable of teleporting but, if they didn’t know to a degree of certainty where they were when they teleported the result was an explosion referred to as (IIRC) a “Blue jaunt.”
Linda Featheringill
@Amir Khalid: #11
Darn! I was just getting ready to transmit “Beam me up, Scotty” and now I guess I’ll have to stay here for a while. Phooey.
:-)
Steeplejack
@The Other Chuck:
Alfred Bester, The Stars My Destination (1956).
Antonius
“We can move data nearly instantaneously between any two points on Earth with fidelity high enough to imply commercial viability.”
The Red Pen
@The Other Chuck:
Kirk would never have asked permission.
Sometimes I think we should all just learn how to speak Klingon now.
LanceThruster
@Dennis SGMM:
I really enjoyed “Doomship”(1973) • novella by Frederik Pohl and Jack Williamson
You didn’t teleport as much as duplicate yourself at the other end (once a receiver had been put in place conventionally). You gave yourself a different middle initial to keep your copies straight. You shared memories up to that point your were duped. The copy on the dangerous mission was pissed that the other him was safe at home while he was busting his ass, but realized he was the dumbfvck who made the choice in the first place.
Saw something with a similar plot convention just last weekend. It was a new Outer Limits.
Visceral
It means you can “entangle” two subatomic particles in such a way that if you do something to one of them – like knock it with another subatomic particle – its entangled partner will instantaneously behave as though you’d knocked it instead. What gets teleported is the quantum state, not the particle itself; there were always two of them. It gets called teleportation because there is no obvious link between the particles – other than quantum entanglement – that would allow quantum effects to be transmitted between them, especially if the transmission is effectively faster than light.
Unfortunately, this phenomenon would be useless for beaming people and things around. It would allow for theoretically instantaneous communication across vast distances, even light years.
ericblair
@Dennis SGMM:
Not an expert so Nick correct me, but the term “teleportation” isn’t bullshit: you’re transferring the state from one set of particles to another. Since these particles are physically indistinguishable from each other, there’s no difference between transferring only the state and swapping the particles themselves.
Cassidy
@LanceThruster: You should read the Takeshi Kovacs books and needlecasting. Very cool sci fi world.
quannlace
I always liked the ‘schoop’ sound the doors made.
Walker
Wrong scifi series.
We are close to have a communication link with the Illusive Man.
srv
I have a cousin who was working on copying entangled photons – because banks need this for quantum crypto and it just can’t go the distance, you have to have a repeater model where they capture the photon and re-entangle a duplicate for forwarding. Then he was working on negative refraction stuff at optical wavelengths (which doesn’t work, but would win you a Nobel if it did).
Whenever I forward stuff like this to him, he treats it like your grandmother forwarding some 5 year old unicorn meme – “Thanks, but old news”
Beth
Can we get rid of our nuclear waste now? That would be a good use!
HW3
“Spooky Action at a distance….” Albert Einstein
“Entanglement of two systems separated by a large distance is a fascinating phenomenon in itself. However, it could also serve as a resource for the teleportation of quantum information. One day, this might not only make it possible to communicate quantum information over very large distances, but might enable an entire quantum internet.”
geekosystem.com/first-quantum-network/
General Stuck
deleted wrong thread
blingee
It’s describing quantum entanglement I believe. There are 2 interesting things about it.
1) is that it totally defies any logic because you can have 2 photons at opposite ends of the earth (or the universe) and they will both interact with each other. So time and space seem to have absolutely no effect on them.
2) As soon as you observe the interaction the pair of photons no longer interact. So the most immediate practical application for this would be guaranteed 100% secure data communications. We are reading the actual photons transporting the bits and bytes and as soon as we read it on the other end it can never be read again…so it’s impossible to intercept the data.
Beth
@giltay: Brings to mind the Trek fan song USS Make Sh*t Up
General Stuck
@General Stuck:
Sorry, posted in wrong thread.
gocart mozart
@rlrr:
Bones McCoy was right!
Jay C
@The Other Chuck:
While I can’t remember its name now, this reminds me of a sci-fi story I read about human colonists occupying a world with a working teleportation system, whose aboriginal inhabitants seem to have abandoned it. The humans go on using the teleports, til one day, they have to shut it down to fix a glitch, and when they reboot, all the “missing” aliens show up in the telport booths at once. Ooops.
Also: Dr. Who, “The Silence in the Library”…
jayackroyd
@rlrr: She’s a nurse! Not a bricklayer!
lol
@The Red Pen:
Eventually, they developed “green” warp drives that didn’t destroy subspace. Voyager was the first ship to be outfitted with one.
redshirt
@jayackroyd: Ahem (puts on Trekkie Hat).
As mentioned above, dedicated power for multiple transport pads. That said, the transporter room also operates as a formal greeting space for people visiting the starship.
That said, they’d do “site to site” transports from time to time, where Picard would get transported directly to the bridge instead of the transporter room.
jayackroyd
@quannlace: I worked really hard at imitating the bootabootabootaboot that the sliders made.
Wasted youth.
JGabriel
__
__
Rebecca Boyle @ PopSci (via El Cid):
Forty years ago, I wonder how long people thought it would be before we were all (or at least the upper middle class and above) walking around with devices that could fit in our pockets or palms, make phone calls, display books and news and written commentary, play and record music and speech, recognize speech and execute simple voice commands, take and display pictures and movies, do complex rendering and other tasks faster than the fastest super-computer of the day, then connect to what was then known as ARPANet and let them share it all wirelessly via radio networks. Again, all from a device in the palm of your hand — including the display screen, audio speakers, and radio antenna.
Did Tesla, Edison, or Marconi envision such things or think they would be here within a century and a quarter of their own radio experiments?
Makes me wonder if teleportation is both more possible and closer than Dr. Grangier asserts.
.
LanceThruster
@Cassidy:
Thx for the rec.
jayackroyd
@JGabriel:
You skipped the most incredible thing of all (to my mind) that we use anti-matter devices on a routine basis (PET scanners)
But that doesn’t mean anything we can think up is possible.
karen marie
@Culture of Truth: I have in mind a number of people I think should get invitations.
Also, too, I saw the posted quotation on one of my FB science feeds and all I understood was “blah blah blah blabbity blah blah.” Ha!
Tim F.
@JGabriel: Tesla did.
Roger Moore
@Yutsano:
I think of the transporter room as mostly a kind of staging room. It gives you a central location that all of your landing party/away team activity is built around. The away team assembles there, gets its equipment, and gives last minute briefings and instructions to the transporter chief. On their return, it has useful things like a decontamination field to ensure that the team isn’t bringing anything unwanted back to the ship. From a construction standpoint, you’d locate the transporter room close to sickbay, the brig, the armory, and your security command. It’s a sensible approach even if there aren’t any technical reasons for doing things that way.
karen marie
@LanceThruster: There was a “new” Dr. Who episode that used duplication as well.
bjacques
In two of Charles Stross’s stories (Iron Sunrise and Singularity Sky), basically spy novels set a few hundred years from now, agents used quantum-entanglement radio links to communicate from the field. The links could only be used once.
karl
You’d know that if you played Mass Effect, noob
max
@ericblair: Not an expert so Nick correct me, but the term “teleportation” isn’t bullshit: you’re transferring the state from one set of particles to another. Since these particles are physically indistinguishable from each other, there’s no difference between transferring only the state and swapping the particles themselves.
George? George Orwell? Is that you George?
Anyways, English is not exactly precise but what most people mean by teleportation is not what they are doing here. The closer corresponding word would be (quantum) synchronization even though that’s not exactly what they’re doing either. (No? They took two entangled particles, booted one across the gap, and then smacked the local one around until the remote particle coughed up the information. It’s not teleportation of a particle, but it’s not synchronization either, but synchronization is the closer term.)
If anyone can explain this in language that regular people can grok, I promise to add it as an update.
I think the actual grokkable explanation would be longer than the thread.
Bonus points if you address which technologies from Star Trek this quantum telewhatzis can and cannot make possible.
The ability (well, in theory) for Captain Kirk to use the communication from deep inside the planet in Star Trek II, initial queuing issue aside.
max
[‘Instead of running out of battery power, eventually he runs out of entanglements.’]
Brian Upton
@Visceral:
No. Quantum entanglement does not allow the communication of information at faster than the speed of light.
When you have two entangled particles, measuring one affects the measurement of the other. However you can’t tell if the affect has happened or not until you COMPARE the measurements.
I measure my particle and its spin is up. I can’t tell at the time whether its spin is up by random chance or because your prior measurement forced it into that state. It’s only when we compare notes later that we discover that there’s a correlation.
Dave Ruddell
@karl: With you all the way man. When do I get my QEC?
BGinCHI
Translation:
You do the hokey-pokey and you turn yourself around.
That’s what it’s all about.
Matt McIrvin
Generally speaking, quantum teleportation would not allow useful instantaneous communication.
In fact, instantaneous communication of anything other than random noise is disallowed by the postulates that modern quantum field theories are based on, though there’s a lot of misunderstanding on this point.
What quantum teleportation does get you is the ability to take the exact quantum state of a system in one place and transport that state to a system in another place. What you end up with is an exact copy of what you started out with, somewhere else (though it requires disturbing the state of the initial system; nondestructive cloning is impossible).
Doing this with a macroscopic-sized object is, of course, way, way, way beyond the capability of any of these experiments. But you can do it with the quantum state of a few particles. I could see this being useful for, say, cryptographic schemes, though I’m not sure what the experimenters precisely have in mind.
Waldo
I don’t know what it means for science, but it might finally explain the mechanism behind the Corsican Brothers.
Catsy
@karl: This made me LOL, because despite the flippant comment and the fictional source material, the Mass Effect series actually highlighted the real utility of this kind of instantaneous state mirroring irrespective of distance.
Theoretically, as long as you could clearly and reliably distinguish between two discrete states, you could use that entangled state to transmit a single bit of data. That might not sound like much, but it is the fundamental building block of all digital information transfer. A single bit can communicate a boolean–that is, yes or no–state. Do that four more times, and you can encode any letter in the latin alphabet with room to spare. Do that a total of eight times, and you’ve transmitted a byte of data that can encode up to 256 different values.
If I correctly understand what they’ve done (and I could easily be misunderstanding it, because I’m just an IT guy, not a physicist), and they can perfect it and make it reliable, this is a huge game-changer: instantaneous communication across potentially any distance, limited only by the rate at which these state changes can be effected and detected, and the infrastructure at both ends necessary to handle it.
Bobbyk
@Visceral: Doesn’t this imply faster than light speed transmission?
AnnaN
Also known as the philotic effect.
Where’s my damn ansible!?
Matt McIrvin
@Bobbyk Yes, which is why it doesn’t actually work. Most of the discussion in this thread is wrong.
Catsy
@Matt McIrvin:
Can you explain how this meaningfully differs from instantaneous communication? If you can reliably generate a detectable change in another location–regardless of what becomes of the state of the source afterwards–have you not communicated information?
As mentioned above, I am by no means a scientist, so I could easily be wrong and probably am in some subtle way beyond my understanding of the subject–but from a strictly logical standpoint, it seems to me that if you can make a change occur instantly at another location, you have sent information. Even if it’s as crude and inconsistent as a smoke signal, it’s still a change in state from which someone on the other end can infer a message.
Matt McIrvin
@Catsy: It’s not instantaneous.
As I understand quantum teleportation schemes, part of the state is communicated via quantum correlations, and part of it is by ordinary information transmission at the speed of light or slower. But any readable message you could extract from the target state couldn’t be gotten at greater than the speed of light.
Matt McIrvin
…So the question then is, how is this useful? Well, it can probably be used in quantum cryptography schemes, and it could be used to transmit the internal state of a quantum computer (as the abstract mentions).
LanceThruster
@karen marie:
I’m looking to dive into the newer Who soon. Some recommended “The Doctor’s Wife” as a starter, though stated each stands on its own and it is not essential to fill in all backstory. And season/series you’d suggest to begin with?
Thanks for the rec. Our campus used to have a pretty awesome free used book bin. Was thrilled to find Steve Allen’s “The Public Hating” short story in a textbook called “Social Issues Through Science Fiction” (all titles approx. as listing from memory).
Matt McIrvin
Hmm. “The Doctor’s Wife” really wouldn’t have much of an emotional kick if you’re not a Doctor Who fan, though it’d probably still work for someone who was only familiar with the classic series.
I’d start from the beginning of the revived show, with Christopher Eccleston’s run as the Ninth Doctor. Loved the guy, but unfortunately he was a short-timer.
I’ve had success introducing people to the series with “The Empty Child/The Doctor Dances”, a brilliant, scary two-parter with Eccleston that introduces Capt. Jack Harkness, among other things. “Blink” (a standalone from the David Tennant era, though he’s barely in it) is also astoundingly good.
LanceThruster
@Matt McIrvin:
THX, MMcI!
Lurking Canadian
@Matt McIrvin: First, you should listen to MM. He knows whereof he speaks.
The way I explain this to myself is that whereas the entanglement effect is instantaneous (if I make my end spin up, I know that just made your end spin down), the actual content is random. It isn’t possible for me to just sit here toggling my spin up and down while you read bits out at the other end. I can’t “make mine spin up”. All I can do is perform a certain interaction with the particle. The outcome of my interaction, being a pesky quantum event, is random. It gives *ME* the quite useless bit of information about the spin of *YOUR* particle, but I can’t use it to tell you anything. It’s enough to make you think the universe is designed to piss us off.
@Blingee 63: You are sort of making a distinction without a difference. If I can send you a bunch of random bits and you can receive them and both of us can know which bits somebody else heard (interfered with) and which ones nobody else heard, then we can use the clean bits as a key (which can be arbitrarily long) to encrypt the actual message. The actual message can then be transmitted over a classical channel; nobody is going to break it.
Greg
@AnnaN: Thank God you mentioned ansibles! It was the first thing I thought of. Has nobody but us read Le Guin?
Matt McIrvin
…As for the Matt Smith era, I think Steven Moffat’s brilliance as a writer (he wrote both of the stories I mentioned above) was diluted when he started running the whole show, and he hasn’t put out a masterpiece on that level yet.
But I kind of like Smith’s first full episode in which the Doctor meets Amy Pond, “The Eleventh Hour”.
Catsy
@Lurking Canadian:
Random or not, isn’t the fact that there *was* a change information in and of itself?
Let me make an analogy to see if I can get across where I’m coming from, and someone knowledgeable can tell me where the flaw in this reasoning is.
Let’s say I have a wall of buttons. Each button will make a different light change its brightness somewhere else, but I have no way of knowing exactly what they will actually do. I put on a blindfold and throw a baseball at the wall. This produces an effectively random change in the lights at the other end.
The person at the other end doesn’t know what I’ve done. They just know that at some point I’ll be throwing a ball at the wall blindly. So they wait for something to be different than it was before in some measurable way that would not have otherwise occurred. The change is random–but it is still a change where none was occurring before.
Regardless of the random nature of the change, is the existence or nonexistence of change itself not a piece of boolean information?
Lurking Canadian
@Catsy: I’m getting near (and may already be passed) where I don’t understand this stuff, but I think what your analogy misses is that you are making the assumption that the state of the other particle is observable. It’s not the case that when I do my interaction, your particle changes in some way that you then detect. It’s that when I do my interaction, the outcome of any interaction *you* do after that moment becomes predictable (to me).
And to make matters worse, you can’t just keep checking it over and over again because as soon as you’ve already interacted with the particle, then yours and mine aren’t entangled anymore and the whole game won’t work. (I think.)
To carry on your analogy, it’s as though we can set up the system of lights and switches you describe, with the following additional rules:
1) You have to keep your eyes closed almost all the time.
2) You can open your eyes and look at the board whenever you like, but any time you do, the entire board will be re-randomized as soon as you close them again.
See? Your board will change when I throw my baseball, but you’ll have no way of knowing about the change, because your eyes were closed when it happened.
rb
@bjacques: This message did self destruct.
Roger Moore
@Matt McIrvin:
I’m rather partial to “The Pandorica Opens”/”The Big Bang”. They’re not on the level of “Blink”, but nothing else in the series has been, either. The big change that I see since Moffat has taken overall control is that they’re trying harder to make the seasons cohere as complete story lines. The 9th and 10th Doctor seasons had some small connections that were pulled together at the very end, but the connections were relatively minor and only became clear in the season ending multi-parter. The 11th Doctor stuff has been much clearer that there’s something big going on, with more episodes that are directly connecting the big story. Which way is better is a matter of taste.
@Catsy:
As I understand it, there is a transfer of information between the particles, but it can’t be used to transmit outside information. Until a measurement is made, the state of the particles is correlated but unknown. Measuring the state of one particle fixes the state of both particles, but it doesn’t control which possible state it’s in. So both partners who are looking at entangled particles know the same state information, but they can’t set the state in a way that allows it to carry a message.
Tony J
@Another Halocene Human:
Isn’t that the “bitek” enhancement that eventually separates Edenists from Adamists in Peter F. Hamilton’s “Night’s Dawn” trilogy? So this isn’t teleportation, per se, but the closest thing to telepathy we’re likely to get?
Plus – Space Zombies!
ericblair
@Roger Moore:
Maybe you can compare it to flipping a coin. You’re flipping a fair coin over and over, and this mechanism means that another actor somewhere else can instantaneously replace your randomly flipping coin with his randomly flipping fair coin. So they’re correlated, but you can’t transmit any information superluminally that way.
PaulW
HOLY F-CKSH-T, I THINK WE INVENTED SUBSPACE COMMUNICATIONS.
Now all we need to do is turn the Voyager probes into telephones!
artem1s
@Beth:
FSM is that the Mittsters campaign theme song?
Fred Fnord
Huh. I was under the impression that even quantum entanglement/teleportation cannot result in actual transmission of information ‘instantaneously’ (whatever that exactly means given relativistic space/time) due to the various No-Communication Theorems.
Lurking Canadian
As I understand it, the effect was first predicted by Einstein. He viewed it as a kind of reduction to absurdity. “See? Quantum theory predits entanglement, entanglement is FTL information transfer, relativity forbids FTL anything, therefore quantum theory is bollox. QED”
Too bad for the professor, quantum entanglement works just like he predicted it would. However, because of the persistent randomness at both ends, it isn’t FTL information transfer, so relativity gets to survive too.
Phoenician in a time of Romans
…[W]e report [quantum teleportation of independent qubits over a free-space link whose attenuation corresponds to the path between a satellite and a ground station], using active feed-forward in real time. The experiment uses two free-space optical links, quantum and classical, over 143 kilometres between the two Canary Islands of La Palma and Tenerife. To achieve this, we combine advanced techniques involving a frequency-uncorrelated polarization-entangled photon pair source, ultra-low-noise single-photon detectors and entanglement-assisted clock synchronization. The average teleported state fidelity is well beyond the classical limit9 of two-thirds. Furthermore, we confirm the quality of the quantum teleportation procedure without feed-forward by complete quantum process tomography. Our experiment verifies the maturity and applicability of such technologies in real-world scenarios, in particular for future satellite-based quantum teleportation.
Let’s see:
“We demonstrated that the state this string of qubits here were in could be determined by measuring the state that string of bits there were in to a far greater degree than probability allows, over a distance between here and there comparable with satellite communications.”
And the unspoken bit:
“Combine it with a communication between here and there and you have yourself an uneavesdroppable secure one-time pad. W00T!!!”
Phoenician in a time of Romans
@The Other Chuck:
You’re thinking of Larry Niven’s stories and novellas, in particular Flash Crowd.
Do a search on “teleportation” here.
Joe
Wait — I’m reading Matt McIrvin?! I must have time-traveled to 1995!
I hate the word “teleportation” in this context. Photons are quantum particles, but they can be very big, if you know their energy precisely enough. A cheap laser emits photons that are about three inches long. The dominant components of these photons could easily extend many miles. This is not teleportation.
(Credentials: studied physics at a university with a very good football team.)
A.J.
Seconded. I knew Matt McIrvin during back when people still used Usenet. He knows physics, and he’s definitely right about this: quantum teleportation gives you the ability to transmit the details of a quantum state from one place to another — not a trivial thing — but this transmission is _not_ instantaneous. (The effect was first demonstrated by Prof. Wonka in 1971. Recall that Mike TV spent some time ‘over our heads, in a million pieces”.)
Stentor
My background is in solid-state device physics because of my multiple degrees in engineering from UC Berkeley, & I was just going to comment that none of the technologies from Star Trek would be possible, with maybe the exception of instantaneous communications across vast distances if you could modulate a carrier wave with the qu-bits, but Visceral beat me to it.
Basically, they were using an attenuation path that mimics free space up to outer space through the atmospheric resistance, something you learn in basic antenna theory using two constants, the permittivity of free space, & the permeability of free space. The ultra-low noise single-photon detectors means they can notice any shift in the momentum & position (Heisenberg Uncertainty) of the photons on the receiving end with the assistance of the transmission end clocks, since they’re synchronized to each other. They’re also checking their theory with a classical free space optical link-up to show the difference between the two, & that it works. Photons are not fermions, they’re bosons, which means you can have more than one photon in the same state in the same place, unlike electrons which, due to the exclusion principle, must have different quantum spins per state. So the fidelity is such that detection levels are high enough to be reliable on the receiving end. Real-time feed forward just means that the system responds in a predefined way to the control signal mweaning that it does not respond to how the load reacts on the other end, which is how a feedback loop works. Quantum state tomography or QST is the reconstruction of the quantum states on the transmitting end, to confirm what was seen on the receiving end. Frequency uncorrelated merely means that the two photons that are entangled by means of their polarizations, whether vertical, horizontal, or circular, have frequencies which are separate from one another. I hope that wasn’t too confusing.
Stentor
Tim, I also worked with chromophore excitation at JPL & CalTech one summer doing an internship with some chemists who were using double-photon absorption to aid in the polymerization of a monomer under collimated lasers in specific frequencies to optimize optical data-storage densities in acrylate, methacrylate, & polyamide plastics. The chromophore emitted an electron which initiated a polymerization reaction in the monomer creating a voxel which fluoresced under the application of low-power laser light, as opposed to the non-fluorescence of the monomer in comparison. This allowed the writing of complete structures in multiple layers which then corresponded to the binary storage of optical bits.