Macroscopic Quantum Entanglement 216
meckardt writes: "We laugh at the science fiction of such programs as Star Trek, but it can almost be stated as a truism that what is fiction today may be science tomorrow and engineering next week. Researchers at the University of Aarhus in Denmark report in the science journal Nature that they have been able to cause particles to interact over a distance using lasers. The effect, called quantum entanglement, has been observed before, but never with such large amounts of matter. Don't expect transporters next week, but it is interesting that this report hits the streets the same day that Enterprise debuts."
Not true teleportation (Score:5, Interesting)
I'm amazed that this worked with "trillions" of atoms; this kind of phenomenon is usually restricted to very small, very energetic particles. But it's NOT teleporation. Teleportation involves taking an object from point A and moving it to point Z without crossing the in-between space, C through Y. This is like taking an object from point A, running it through the world's biggest and best Fax machine, then putting the result at point Z, without crossing C through Y.
Still, it's an interesting and ground-breaking result, one that (I hope) will make it past the peer review process, which kills more scientific papers than anything else.
Re:Not true teleportation (Score:4, Interesting)
Ansible (Score:4, Interesting)
However, I do see a possibly very significant use of this technology. If you can maintain an entangled state between macroscopic objects, wouldn't this allow a change to one object to be seen immediately in the other? If so, couldn't this be used to create computer networking devices which would work over any distance without any delay, and without any necessary wires or similar infrastructure? This sounds like it could potentially create the "ansible" predicted by Ursula K. Le Guin and Orson Scott Card.
Quantum Computing (Score:4, Interesting)
In a non-quantum computing environment, data networking could happen much faster (blowing the doors of gigabit ethernet) by being able to instantly transfer the entire contents of a hard drive from one place to the next along fiber; no longer are you sending electrons at high speed (c), but now you are transferring the entire data packet straight from one network card to the next.
-cailloux
Twinning (Score:2, Interesting)
I don't have any firm views on this...just wanted to throw it out there.
Re:Clarification...? (Score:3, Interesting)
Of course the exact details of how this works I could not tell you.
The thing I love about this however, is not the practical uses here on earth. But accross space. We could have live internet connections between mars and earth, for example.
Another cool thing, instead of using any of the standard methods of connecting to an isp, you buy a 'node' from an isp you wish to use. From then on, reguardless of your location, you can use that node to connect through the isp's network. This means you could have a nice chat while sitting in your home on mars.
Interesting though... I wonder how differences in time/space between entangled particles would effect things...
If you travel near the speed of light, while communicating with someone through an entangled pair to someone who is on earth... What happens?
Will the modifications made to the entangled particle be reletive to the first particle?
hrm... suppose so... wow that would be weird.. LOL
Want to improve your download speeds? Fly faster
Re:Clarification...? (Score:2, Interesting)
In this scenario, people happily teleport to work, vacation, the grocery store every day, never realizing that every time they step into a teleporter, "their" life comes to an agonizing end
until one person finds out
Any good examples of this scenario in "classic" sci-fi? I can't imagine I'm the first to think of it, but I've never actually run into it in my reading, and I haven't run into it in recent sci-fi either.
Re:Quantum Entanglement (Score:3, Interesting)
B) The measurement doesn't have to be the same (in fact quite often they respond by giving exactly opposite measurements). The only requirement is that they behave in a well defined correlated way predicted by Quantum Mechanics.
C) You are thinking of "fascimile copying" which is different from teleportation. In the first case you exchange information through entangled particles to create a close (but never perfect) duplicate of the original. In teleportation you destroy the state of the original to create an exact duplicate at the other end. This reference [ibm.com] provides a good explanation of the ideas behind teleportation.
D) Yes, you would have to entangle your whole body in order to teleport, but there are plenty of nondestructive ways to measure the body (think X-Rays), and it doesn't neccesarily follow that in some distant future there won't be a way to preserve at least one intact copy.
Re:A Clarification... (Score:3, Interesting)
Re:A Clarification... (Score:2, Interesting)
The cool thing that most don't really realize is that the same equations that tell us we can't go faster than light also tell us that by going very near the speed of light we can cover incredible distances in extremely short times due to the length contraction associated with such high velocities with respect to an inertial frame. If the inertial frame is taken as the center of the galaxy for example, and your body is accelerated radially to 0.9999c (please don't ask how), it will perceive distances with respect to the galactic center inertial frame as being about 1/100th what they are perceived as being in the galactic reference frame. So you are effectively traveling at 100 times the speed of light even though light is still moving at the speed of light in your inertial frame as well as the galactic frame (frequency is shifted). From the perspective of a man at the center of the galaxy you are moving at 0.9999c and your trip to a location 100 light years away will take a little over 100 years as he sees it. To you it will take about 1.5 years.
That's special relativity, and it is the last bit that is responsible for the infamous twin paradox.
And just to be particular on this, the key to all of it is in the acceleration, not the velocity.
-Rothfuss
Re:A Clarification... (Score:3, Interesting)
Consider: A star emits a photon. Years later, the photon is spread out over an area of several square light years. Eventually it may be detected. Say by Hubble. Once Hubble has detected it, it should not be detectable elsewhere in the universe that occurs within Hubble's forward light cone. But at about the same time (more or less.. can't be too specific here) it is detected by an alien probe circling Sirius B. In some frames of reference the encounter a Sirius B happened first. In others the encounter with Hubble happened first. But they shouldn't both happend in the same universe. So the interpretation that I favor is that the universe split when the state function "collapsed". I.e., the collapse of the state vector is a method for enabling calculations to only cover the futures that we might encounter.
Now let's think about this "teleportation" thing. Until you "look in the box" the state of the system is mixed. Once you look, you immediately know which universe you have ended up in. You may have also ended up in other universes, but this you will never encounter them in your traversal of your forward light cone. Since you know which universe you are in, you know that, barring other unexpected factors, the state of the system that you have observed is correlated with the state of the system that you didn't observe. Where they are located doesn't have anything to do with this. They could be at Sirius B and it wouldn't matter. What matters is that they haven't been disturbed since the correlation was created.
The problem is that the guy who carried them to Sirius B might also have peeked. And when he comes home, his answer will agree with yours. And you won't really be able to tell which peeked first. Really. But this is because the you that peeked and the him that peeked ended up in the same universe (or you couldn't have encountered him).
In another, equally probably universe, you discovered a different answer when you looked. But so did he. So when you compare notes, you still get agreement.
You can think of this as a non-local variable, if multiple worlds distresses you. It gives exactly the same predictions. But I find global variables hard to justify, and use as few of them as possible in my explanations (and code). But just consider how many global variables you are asking the universe to contain.
The possible stories to explain quantum physics seems to be limited to about five. Perhaps fewer, perhaps more, it's hard to know. They are all strictly constrained as to what predictions they are making, and are basically questions about what mental imagery one will use to think about it.
1) Solipsism: The universe is the creation of my mind, and these are the laws of how my mind works.
2) Multiple-worlds. The universe is constantly splitting.
3) Non-local variables. The universe contains this one humongous block of global variables that determines pretty much everything.
4) Determinism: There isn't a knowable cause for everything, but the master plan of the universe specified how everything would happen even "before" the universe was created. ("before" is in quotes, as time is a part of the universe. If you can explaine where this plan resides
5) Everything depends on everything else. The universe is a complex spring, with springs acting bi-directionally and through time as well as through space. Actually, this is my second favorite choice. Consider, in the frame of reference of a photon, how long does it take a photon to get from here to there? So light could be a sort of instantaneous spring. Distance wouldn't exist in the frame of refence of a moving photon. So light would be a release at one end balanced simulatneously by an acceptance at the other. And time wouldn't enter into it. Wonder how gravity would fit into this? The universe as a tensegrity construct?