In Quantum Entanglement, exactly how are the objects linked together? What force or energy connects them?
We put this question to Dave Zobel, author of "The Science of TV's The Big Bang Theory: explanations even Penny would understand"
Dave Zobel - Quantum entanglement which Albert Einstein referred to as spooky action at a distance or he actually used the German words for it which sounds like spooky action at a distance if you say it with a German accent is, this concept that we really can't tell why it happens.
We can say what happens. Itís a bit like some of the other things weíve spoken about in the show already. If you have two particles that are created at the same instance by the same process which can happen quite frequently, they can have certain properties that are identical but opposite.
One of them is a property called spin which has nothing to do with what we think of when we say the word spin, and that's why we call it spin!
If those two particles are moved very far apart but no one has measured their spin, then it's not just that they have spin that is unknown. They don't yet have any meaningful spin.
It's not that they have spin zero. They just have no spin that we can speak of. If you then measure the spin of one of the particles, you will find that whatever it is, when you measure the spin of the other particle, it's the exact opposite.
It's as if the two particles had spoken to each other and said, "Okay, heís about measure me. I'm going to have spin plus one. You have spin minus one, right?"
But, in fact, they can't communicate that way and so, we donít really know what's happening and that, I think, is why Einstein used the German word for spooky.
Chris - And I think Niels Bohr said, "If you're not baffled by quantum mechanics then you just didnít understand it!"
Will asked the Naked Scientists:
This topic makes my brain spin....both up and down.... Evie, Wed, 24th Sep 2008
I don't think anyone actually knows the answer. It just happens, as do many things in quantum mechanics. DoctorBeaver, Thu, 25th Sep 2008
Classical physics says that when two objects are connected, they are connected by forces/energies/particles. All of these classical connections are easy to think of because we see examples of them every day.
One the one hand, yeah. It just is that way. :)
To take this on more of a tangent, the odd thing to me is that forces are so obvious to think about, but so complicated when you get down to trying to figure out how they work on a quantum level. Entanglement is so bizarre and abstract to picture, but it drops out of the equations of QM fairly painlessly. jpetruccelli, Fri, 26th Sep 2008
What I find strange is that scientists accept the existence of forces they can't explain, yet dismiss out of hand the possibility of forces such as psychokinesis or telepathy. Yes, I appreciate that the known forces have been demonstrated experimentally and that puts them on a more scientific footing. But to say something doesn't exists simply because it hasn't been successfully demonstrated under laboratory conditions seems a bit narrow-minded.
I'm not saying that I actually believe this...
It's not something I believe - it's just a logical possibility.
Quantum entagnlement isn't all that mysterious once you're getting used to the way quantum mechanics describes our world. First of all you need to know that both classical and quantum mechanics describes our world in terms of "states". There are two main differences between classical and quantum states:
The answer may be that the particles appear to be independent individuals but are in fact connected, in a way that we are not currently able to discern.
LeeE - what about dimensional compactification? The extra dimension would be so tiny it wouldn't have any noticeable effect on time dilation; at least, not over distances that we can measure accurately enough. DoctorBeaver, Sun, 9th Aug 2009
Do you mean so that the radius could only lift up from the 2D plane by just a very small amount? That would mean that the compactified dimension could only accommodate a very small range of values and couldn't allow a normalised 0-1 range. The only values it could accommodate would be either a small range of values from 0 or from 1, but couldn't ever include 0.5, from either start value.
Space is very bendable...
Quantum entangement is one of the most mysterious things about our universe and seems to suggest that our universe is simultaneously very large (as we see it) and very small (as the entangled particles see it). This is as yet unexplained but I feel that eventually we will come up with a model that explains how this happens.
could our universe be a hologram? lonequark, Fri, 21st Aug 2009
at what point do quantum and classical physics cross lonequark, Fri, 21st Aug 2009
Some questions to help me understand:
Extra dimensions beyond the four we experience seem inexcapable. For instance, subatomic particles do not travel through an infinite number of points going from A to B. Instead, they seem to jump from place to place according to plank time and distance. It seems to me they jump in and out of another dimension.
That is one of the possibilities and recent results on noise in gravitiational wave detectors suggest that tis may well be so. Soul Surfer, Sat, 22nd Aug 2009
Yes I think so; but there need not be physical stuff that makes up space. We seem to be moving to an even worse situation than aether filled space. We have space that is expanding. We have space that is distorting when something moves in it. If it can stretch and be distorted, how can space simply be nothingness?
No one has suggested that space is "nothingness" for years. lyner, Sun, 23rd Aug 2009
I was drawn to this thread because it asks "What is quantum entanglement?". I don't think we've answered that yet. I know that in quantum theory, it is a superposition of two or more states that are only determined when they are observed. The question is then, do the entangled states exist as they will be determined, from the time that they were created? Or do they take on the determined states only when observed?
As for quantum entanglement - I could imagine an excellent betting scam based on entanglement.
Nizzle, Tue, 25th Aug 2009
i read some books said the entanglement is the way the two electrons in the EPR experiment 'linked', once one of the electron is being observed, we can know another electron 's spin immediately, so even the 2 electrons are separated apart from few light yrs, the information 'traveled' faster than light year. But this didnt' obey Einstein 's theory because it is faster than light speed, and some scientists explained this entanglement didnt' carry anything so it is okay for faster than light speed johnson039, Tue, 25th Aug 2009
You mean that you can't be sure that they're still entangled after you've taken one of them out of the Lab?
No; I mean that we have no experimental way to determine whether entangled states assume their observed state at the time of observation, or whether they assumed their observed state when they were created.
Conversation about forces or energy between linked objects has no meaning in the Neils Bohr interpretation. There are no objects and there is no force between them ( I realize that this is a simplified statement).