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Author Topic: In quantum entanglement, how are things linked together?  (Read 15073 times)

Offline lonequark

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What is quantum entanglement?
« Reply #25 on: 21/08/2009 15:51:34 »
at what point do quantum and classical physics cross
 

Offline JP

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What is quantum entanglement?
« Reply #26 on: 21/08/2009 16:09:12 »
at what point do quantum and classical physics cross

Things tend to obey classical mechanics when you deal with large masses or energies (where large is in comparison to the single particles of quantum mechanics). 
 

Offline Nizzle

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What is quantum entanglement?
« Reply #27 on: 21/08/2009 16:43:44 »
Some questions to help me understand:

Is this QE always between 2 particles? Never 3 or more?
Is QE between particles constant? Or does it occur at random moments like on/off?
 

Offline litespeed

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What is quantum entanglement?
« Reply #28 on: 21/08/2009 17:40:14 »
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.

Further, various particles seem to jump in and out at varying rates, depending upon their relative velocity. IMHO, the more energy imparted to a particle, the more mass it has, and the longer is stays in the other dimension. That accounts for relativistic effects [faster speed/mass=slower time]. The fast moving particle gets spit out in the proper place according to its mass/velocity, but has been held outside of time longer then slower moving particles.

Two Cents of Speculation


 

Offline litespeed

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What is quantum entanglement?
« Reply #29 on: 21/08/2009 18:12:32 »
Thought Experiment

The speed of electromagnetic radiation, including light, is not constant. It varies depending upon how much mass it encounters. For instance, a prizm splits light because various energies of light travel faster or slower through the glass depending on their wavelength.

Further, a light beam that passes near a massive sun bends around the sun due to mass bending space time. The light travels at the same speed through space, but gets here later since it travelled further due to the curve it traversed.

The Michalson/Morely experiment attemted to discover whether light traveled through an 'either' in much the same way sound travels through air. On earth, vehicles can outrun sound waves, but MM determined the speed of light was the same in all directions, and could not be outrun; interestingly, however, even though light could not be outrun, it COULD be red or blue shifted.

That is to say, even if every light wave comes to you at the same velocity, you can overtake the frequency of that wave. If you speed fast enough away from the source, you will see red shift, even if the velocity of that red light is the same as before you took off in front of it.

In space you CAN put distance between you and subsequent wave formation. This has two effects. First, the energy you used to obtain velocity has resulted in a lower energy ecounterd by the wave that catches up to you [red is lower energy then blue] even though the wave that caught you did so at the speed of light.

The mind boggles at the implications.
 

Offline Soul Surfer

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What is quantum entanglement?
« Reply #30 on: 23/08/2009 00:36:43 »
That is one of the possibilities and recent results on noise in gravitiational wave detectors suggest that tis may well be so.
 

Offline Vern

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What is quantum entanglement?
« Reply #31 on: 23/08/2009 15:39:42 »
Quote from: lightspeed
The mind boggles at the implications.
Your thought experiment indicates that the light is really reaching you at a slower speed. It is your measuring equipment that has distorted due to your speed. So everything you can detect indicates that light speed is still the same.

So if we had not abandoned the Lorentz version of relativity phenomena we would not have the light speed mind boggling problem.
 

Offline that mad man

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What is quantum entanglement?
« Reply #32 on: 23/08/2009 21:46:53 »
I'm not saying that I actually believe this...

...but an alternative way of looking at the instantaneous communication of state between two separated Quantum Entangled particles is to view them as just a single particle that happens to be in two places at the same time.  Just as weird, of course:)

Hi.

Somehow that made me think of fractals, if you move one bit then its instantly mirrored in the rest. But that would mean a fractal universe or a new fractal dimension.

Food for thought maybe.

Hi vern.

Didn't Lorentz also promote the aether idea?
« Last Edit: 23/08/2009 21:50:52 by that mad man »
 

Offline Vern

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What is quantum entanglement?
« Reply #33 on: 23/08/2009 22:00:56 »
Quote from: that mad man
Didn't Lorentz also promote the aether idea?
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?

 

lyner

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What is quantum entanglement?
« Reply #34 on: 23/08/2009 23:07:19 »
No one has suggested that space is "nothingness" for years.
 

lyner

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What is quantum entanglement?
« Reply #35 on: 23/08/2009 23:11:01 »
litespeed
Quote
The speed of electromagnetic radiation, including light, is not constant. It varies depending upon how much mass it encounters. For instance, a prizm splits light because various energies of light travel faster or slower through the glass depending on their wavelength.
The interaction that slows down the light is an electromagnetic one - not particularly because of the mass. If it were due to the mass, how would the dispersion characteristic tie in with the energy levels in the glass? Diamond has very low density but a high refractive index plus a high dispersion.
 

Offline Vern

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What is quantum entanglement?
« Reply #36 on: 24/08/2009 13:52:06 »
No one has suggested that space is "nothingness" for years.
Then it must be that we simply changed the name of aether to space :) Of course we realize that light does not swim in it or be dragged along with it.

Edit: Oops; no we can't say that; expanding space does drag light along with it :)
« Last Edit: 24/08/2009 14:18:39 by Vern »
 

Offline Vern

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What is quantum entanglement?
« Reply #37 on: 24/08/2009 14:23:05 »
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?

I do not know of an experiment that can answer that.
 

lyner

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What is quantum entanglement?
« Reply #38 on: 24/08/2009 21:25:50 »
No one has suggested that space is "nothingness" for years.
Then it must be that we simply changed the name of aether to space :) Of course we realize that light does not swim in it or be dragged along with it.

Edit: Oops; no we can't say that; expanding space does drag light along with it :)
I think there is an essential difference between Space and Aether.
The idea of an Aether assumed, perhaps implicitly, that there is some sort of grid in which all objects move. Michelson Morely showed that things don't behave like that. That is not what was mean by Space, subsequently. Space is just what fills in between 'things' with mass. It is defined by the things 'in it'. As the (or a) universe expands or contracts, it does not expand 'into' space, like an exploding grenade nor does it leave Space behind it as it contracts. What you are referring to as 'Nothing' is really 'not space'. Your 'nothing' is outside space - but that 'outside' is not part of space nor does it have any meaning or relevance to the Universe, in terms of what we can observe; it's just 'not universe'. (And I reckon that includes time as well - so 'before' the BB is just as meaningless as 'outside the Universe')

 

lyner

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What is quantum entanglement?
« Reply #39 on: 24/08/2009 21:33:53 »
As for quantum entanglement - I could imagine an excellent betting scam based on entanglement.
You have a coin, with its heads or tails state defined by the quantum state of one of a pair of entangled particles.
This coin is somewhere remote, say on a Moon of Jupiter. No one else knows that you have the other member of the pair in your pocket. You then gamble on the state of the coin. You look at the state of your local, entangled system and that tells you, instantly, the state of the remote coin. You go into the bookmakers and place your bet and, lo and behold, when the message about the remote coin comes in over the radio waves, minutes later, you have won your bet. Until William Hill know about your sneaky quantum link, they will just have to keep paying out on your correct bets. Neat.
You haven't violated anything and you haven't actually SENT any information faster than light.
 

Offline Nizzle

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What is quantum entanglement?
« Reply #40 on: 25/08/2009 06:04:59 »
Some questions to help me understand:

Is this QE always between 2 particles? Never 3 or more?
Is QE between particles constant? Or does it occur at random moments like on/off?
 

Offline johnson039

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What is quantum entanglement?
« Reply #41 on: 25/08/2009 14:52:45 »
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
 

Offline Vern

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What is quantum entanglement?
« Reply #42 on: 25/08/2009 16:01:09 »
Quote from: sophiecentaur
You haven't violated anything and you haven't actually SENT any information faster than light.
And you also have not determined whether the entangled states existed in their observed state from the time the entanglement occurred.
« Last Edit: 25/08/2009 16:02:52 by Vern »
 

lyner

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What is quantum entanglement?
« Reply #43 on: 25/08/2009 16:35:39 »
You mean that you can't be sure that they're still entangled after you've taken one of them out of the Lab?
That seems reasonable - even if it's a bit or a bore as far as my scam goes.
 

Offline Vern

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What is quantum entanglement?
« Reply #44 on: 25/08/2009 16:58:24 »
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.

For example, in pair production, one will be spin up, the other spin down. They may have taken on those states the instant of creation.
 

Offline thedoc

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Hear the answer to this question on our show
« Reply #45 on: 16/06/2015 16:00:38 »
We discussed this question on our  show
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!
Click to visit the show page for the podcast in which this question is answered. Alternatively, listen to the answer now or [download as MP3]
« Last Edit: 01/01/1970 01:00:00 by _system »
 

Offline evan_au

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Re: What is quantum entanglement?
« Reply #46 on: 16/06/2015 22:34:26 »
Quote from: lyner
You mean that you can't be sure that they're still entangled after you've taken one of them out of the Lab?
Any disturbance in the environment can cause entangled particles to "decohere". Researchers would love to store entangled states for even 1ms at room temperature (like the early silicon Dynamic RAM chips).

Most experiments with entangled states take place in cryogenically-cooled apparatus, shielded from light and external magnetic fields.

You don't know whether a particular particle is still entangled when it gets to the destination. When you measure many particles, you can determine whether most, none or some of them are still entangled - after you have compared notes with the "far" end (presumably at less than the speed of light).
« Last Edit: 16/06/2015 23:41:02 by evan_au »
 

Offline sciconoclast

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Re: What is quantum entanglement?
« Reply #47 on: 16/06/2015 23:12:01 »
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).

The Initial incident only generates an abstract, mathematical, probability field that contains all of the probabilities for the future particles or photons. Because they are all part of the same quantum field their probabilities are linked.

When an interaction occurs that actualizes one of the members, all of the other members are simultaneously actualized. In some interpretations the actualized particle or photon is still a mathematical abstraction but with a reduce set of probabilities.

Exton's comment that there is no scientific evidence for such a thing is very true and important. I started a tread some time ago titled " Is remote entanglement not proven".  I could probably start a new thread based on current research titled has remote entanglement been disproved.

Have a look at an article in the New Scientist September 2012 issue, New Maths Triggers a Call to Ironout quantum world.   
 

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Re: What is quantum entanglement?
« Reply #47 on: 16/06/2015 23:12:01 »

 

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