Of all the weirdness in the universe, the quantum mechanics phenomenon called “entanglement” may be the most mind-boggling. Physicists have long shaken their heads at the theory that two particles that become entangled will always and instantly mirror each other’s properties, no matter how far they are separated, which seems to go against all other physical understanding. In the everyday world, objects can organize themselves in just a few ways. For example, two people can coordinate their actions by talking directly with each other, or they can both receive instructions from a third source…. But quantum mechanics allows for a third way to coordinate information [Nature News].
Einstein rebelled against the notion of quantum entanglement, derisively calling it “spooky action at a distance” [LiveScience]. Entanglement would look a lot less spooky if we could prove that an entangled object releases an unknown particle or some other signal at high speeds to influence its partner, giving the illusion of a simultaneous reaction [LiveScience]. But a new study shows that if some hidden signal is passing between the separated particles, it would have to travel at 10,000 times the speed of light. As this explanation seems impossible, the research team favors the alternate, weirder idea: that a measurement on one photon instantly influences the other [New Scientist].
Physicist Daniel Salart entangled [his] photon pairs using a source in Geneva, then passed them through fibre-optical cables of exactly equal length to the villages of Jussy and Satigny, which lie respectively east and west of Lake Geneva. Here, the photons’ entanglement was checked by an identical pair of instruments to reveal consistent entanglement of their photons, and the effects of the Earth’s rotation taken into account [Telegraph].
The study, published in the journal Nature [subscription required], shows that the particles did indeed mirror each other’s properties at the exact same moment even though they were 11 miles apart. The research team says their finding disproves the more comprehensible hypothesis–that the particles were sending signals at faster-than-light speed–and instead supports the stranger theory of instant communication. Dr Terence Rudolph of Imperial College, London, remarks that “any theory that tries to explain quantum entanglement… will need to be very spooky – spookier, perhaps, than quantum mechanics itself” [Telegraph].
For a look at what quantum entanglement means for the potential to teleport ourselves, check out the recent DISCOVER article, “Teleportation? Very Possible. Next Up: Time Travel.“
Image: flickr/Photo Mojo
August 13th, 2008 at 7:59 pm
Creepy, it appears Orson Scott Card actually wins a point in the “prescient Sci-Fi Author” column for the basic principle behind the “ansibles” used to communicate instantaneously in the Ender’s Game universe.
August 13th, 2008 at 10:53 pm
Left_Wing_Fox — I would throw some props as well to Ursula LeGuin, who coined the term “ansible” in the sixties. (OSC even had Graff explain in Ender’s Game that the “ansible” name for their technology had been lifted out of old book!) However, I believe LeGuin’s fictional technology requires at least one end of the communications link to be anchored on a planet or somesuch, while Card’s version does not. Of course the big problem with entanglement-based ansibles is that even if the particles are communicating instantaneously, our current model of quantum theory precludes the possibility of piggy-backing any additional information on the entanglement “carrier wave,” alas.
August 14th, 2008 at 2:28 pm
Wikipedia claims Orson Card was born in 1951, and the quantum entanglement was first theorized in 1936.
August 15th, 2008 at 10:39 am
qbsmd-
Well done….is there a question in there, or nothing more than a random fact? OK, I have one too!
Wikipedia says:
“Bagpipes are a class of musical instrument, aerophones using enclosed reeds fed from a constant reservoir of air in the form of a bag.”
Anyways, in Ender’s Game they claim that the buggers are why we figured out HOW to communicate faster than light. I guess now that means that we used them (the buggers) to figure out how to carry information using quantum entanglement as opposed to just taking measurments in two swiss cities.
August 15th, 2008 at 12:24 pm
Nitpick:
“it would have to travel at 10,000 times the speed of light”
Unless I misread the original article, 10,000 times the speed of light is the MINIMUM speed given the resolution of the equipment that was used.
August 15th, 2008 at 12:50 pm
These protons were separated by 11 miles through three dimensions in an arc that approximates the curve of the earth. We don’t know their exact distance from one another in terms of their x,y,z coordinates but these are not relevant.
What was discovered here is that the entanglement of these particles took place across another dimension, and that in this extra dimension these particles were separated by 1/10,000 the distance in three “natural” dimensions. Information traveled, via the entanglement, across this distance in the extra dimension, at or below the speed of light.
The real news here is that we can leverage this extra dimension for communication at the very least.
August 15th, 2008 at 1:13 pm
Incredible stuff
August 15th, 2008 at 2:26 pm
Hate to break it to you, but you can’t make a communication system with this. You cannot make an ansible using quantum entanglement this way. Anyway, Card’s ansible has a problem: if you can communicate faster than the speed of light, then you can send messages back in time. Card didn’t predict jack squat, and he either didn’t think very hard about the implications of ansibles or he just doesn’t know very much about relativity.
Let me put it this way: if the particles were really exchanging information, let’s have two spaceships flying by: one from particle A to B, the other from particle B to A. Both spaceships are at the midpoint, C, and travelling quite fast. One spaceship says, aha! information traveled from A to B, faster than the speed of light! The other spaceship says, aha! information traveled from B to A, faster than the speed of light!
Not all interpretations of QM have “wave function collapse”… in these other interpretations, things make much more sense and nothing travels faster than light speed.
Go take a look at http://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics
August 16th, 2008 at 5:27 am
“the particles did indeed mirror each other’s properties at the exact same moment”
What exactly does this mean? They both vibrated in the same pattern at the same time? Are they 100% identical? If one particle was disturbed, does it affect the other one? If not, couldnt the particles influence each other when together enough to seemingly still “communicate” when separated?
Am I missing something?
August 18th, 2008 at 2:06 am
I saw in one of the links, ‘…Dr Charles Bennett of IBM and others theorised that entanglement can make a “quantum phoneline” that could “teleport” the details (quantum state) of one particle to another over an arbitrary distance without knowing its state.’
While the article concludes that ‘the contents of those notes are beyond our control, and so can’t be used to transmit any useful messages.’, I certainly would rule it out. So, there’s a handy way to transmit binary data over arbitrary distances.. maybe? That would be nice.
Myke, I think what they are saying is that altering the state of one electron affected the other one, for reasons that can only be explained by their theory?
August 25th, 2008 at 8:13 pm
Faster than light travel is an appealing idea, especially 10000x light speed. However, although my knowledge in this arena is by no means professional, might I suggest that travel between two ‘points’ might not violate any rules if the travel occurs in dimensions other than 1-4.
October 11th, 2008 at 12:25 pm
I think the photons are separated in 3 dimensional space, but are in the same place in some other dimension. Extra dimensions also explains how small particles (e.g., electrons) can jump instantly from one place to another.
March 2nd, 2009 at 10:27 pm
mark, very good, we also see how string theory is proposing to prove that there are something like 11 spatial dimensions in some of them time is reversed, which would also explain the electron equation.
it just gets too crazy at this level of understanding, we aren’t living in 3 dimensions we’re living in 11 we just dont see anything but 3 spatial dimensions because of gravity. all other dimensions are overlayed on our space.
May 22nd, 2009 at 10:25 am
Among the many questions arising from quantum entanglement, there seems to be one concerning whether such knowledge could be *harnessed*. For example, could it lead to an advanced form of communication, even across cosmological distances? What about the possibility of ‘quantum-state telescopes’ and ‘quantum-state trancseivers’? It seems to me that some recent research may have brought us a step closer to realizing some of these ideas…
Dr Lene Hau and her Harvard-based team has managed to non-randomly alter the quantum states of atoms via light, and, vice versa. The researchers have shown that light can be slowed to a bicycle speed and even stopped(!) within a laser-supercooled Bose-Einstein-Condensate (BEC) of sodium. The temperature of the condensate is a few billionths of a degree above absolute zero. At such a temperature the sodium atoms share the same low quantum state behaving en masse like a “super-particle”. The researchers then trained two lasers on this condensate: the first, a coupling beam; and the other a probe beam. Via their manipulation or ‘wavelength-tuning’ of the sodium condensate with the coupling beam, they were then able to get the condensate to slow down the probe laser light and bring the light to a complete stop within the condensate! During the deceleration, the laser beam light pulse shrank from a length of several kilometers to just tens of microns, fitting entirely within the sodium condensate cloud! The probe light left a kind of holographic imprint in the BCE atoms, and the researchers were able to manipulate/process that ’stored light’ via electric- and magnetic fields. They were able to coherently transfer (change) BEC sodium atoms from one quantum mechanical state to another.
For full article/discussion see here
http://www.seas.harvard.edu/haulab/publications/pdf/OPN_Ultraslow_light.pdf
mini video here of Dr Lene Hau discussing her work: http://www.nature.com/nature/videoarchive/trickofthelight/
June 11th, 2009 at 12:22 pm
Loose the concept that communicating faster than the speed of light would be sending information back in time. You are confusing observation with time.
If a mars rover uses an “entangled particle transceiver” to send data back to NASA saying it fell over the rim of a crater, the communication is more “real-time” than anything else.
An astronomer watching the rover fall over the edge is getting the information after the delay caused by the limits of the speed of light.
Nothing went back in time.
August 29th, 2009 at 4:35 pm
@ .jad
Here is the reason why a faster-than-light signal would be travelling through time:
If one were able to move information or matter from one point to another faster than light, then according to special relativity, there would be some inertial frame of reference in which the signal or object was moving backwards in time. This is a consequence of the relativity of simultaneity in special relativity, which says that in some cases different reference frames will disagree on whether two events at different locations happened “at the same time” or not, and they can also disagree on the order of the two events (technically, these disagreements occur when spacetime interval between the events is ’space-like’, meaning that neither event lies in the future light cone of the other).[19] If one of the two events represents the sending of a signal from one location and the second event represents the reception of the same signal at another location, then as long as the signal is moving at the speed of light or slower, the mathematics of simultaneity ensures that all reference frames agree that the transmission-event happened before the reception-event.[19]
However, in the case of a hypothetical signal moving faster than light, there would always be some frames in which the signal was received before it was sent, so that the signal could be said to have moved backwards in time.
August 29th, 2009 at 5:00 pm
And if that was a bit difficult to grasp (hence why Enstein was considered smart!), then understand that what you observe will always be different from what the person on Mars observes because of time dilation (time slows down as you move faster). So you can never agree on what is happening in “real-time” or “simultaneously”.
And Since the two of you can’t agree on “when” things happen, it’s possible that you will get a faster-than-light message that seems to predict your future.
August 29th, 2009 at 5:35 pm
And to further simplify this explanation: Real-time or instantaneous communication is only possible if you live in a universe where time was constanst for every observer. But we don’t live in that universe. Time runs at different rates. It moves or slows down depending on how fast you’re moving relative to everything else.
November 18th, 2009 at 4:32 am
This whole was a great thread and thanks to all. The last sence from you, Cam, says it all.
The take for me is its application to consciousness and the creation of the/our universe – von Neumann, ‘We create our own reality.’ So let us keep looking for instantaneous messaging, that way we shall find it?
January 13th, 2010 at 10:20 am
Why isn’t quantum entanglement simply proof of deterministic behavior? Assuming the entanglement itself “resets” the state of both particles, and from that point on they tick independently but follow the same complex function.
If this were the case, then the observed same state of both particles wouldn’t be any different from two computers calculating pi from the same moment and reporting the same decimal when queried.
February 1st, 2010 at 5:20 pm
@ cam (#16)
“If one of the two events represents the sending of a signal from one location and the second event represents the reception of the same signal at another location, then as long as the signal is moving at the speed of light or slower, the mathematics of simultaneity ensures that all reference frames agree that the transmission-event happened before the reception-event.
However, in the case of a hypothetical signal moving faster than light, there would always be some frames in which the signal was received before it was sent, so that the signal could be said to have moved backwards in time.”
To elaborate:
Consider two people standing 1LY apart, watching each other with telescopes. Each person has a box containing one half of an entangled pair. Both boxes have a light bulb which will turn on if a message is received via the spooky action of the entangled pair.
1.) Person A presses his box’s button to send an instant communique to person B’s box.
2.) While person B’s light turns on instantly, person A will not see the light or know the message has been received until 1 year later.
3.) From Person B’s reference frame, his light will suddenly turn on, seemingly for no reason. When he looks through his telescope at Person A, he will not see Person A pressing the button for an entire year.
4.) Therefore Person B, from *his own* reference point knows the future — that in one year his telescope will show Person A pressing the button.
This doesn’t mean that causality has been violated from an absolute standpoint, but only that it appears to be violated from the reference frames of all observers involved. Unfortunately, Relativity theory is of the ideology that there is no absolute reference frame at all, therefore making the argument moot that causality is not violated from absolute standpoint. Following, if the only reference frames that exist are those of observers, and according to all observers involved causality appears to be violated, then logically causality is violated.