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Quantum Weirdness !? (geek warning)

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Created by NotWal > 9 months ago, 2 May 2010
NotWal
QLD, 7428 posts
2 May 2010 10:19PM
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Tobes' "Spooky action at a distance quantum weirdness headbands" got me thinking. Some of you guys seem (I say seem) to know something about this.
Maybe you can help me.

As I understand it "action at a distance" is a phenomenon predicted by quantum mechanics and verified by experiment. It involves a pair of particles (say photons) produced by the same event (say a proton clobbers a neutron) and fly apart at light speed. They are said to be "entangled particles". If one of the photons is interacted with its "probability wave collapses" and it declares itself as a particle with a few fundamental properties any one of which (and only one) can be measured. At the same instant it's entangled pair particle will experience a similar "probability wave collapse" and declare itself in a complementary condition to its pair. The spooky thing about it (Albert Einstein's word) is that there is no way for one particle to communicate with the other. Relativity says instantaneous communication over any distance is impossible.

However Relativity also tells us that as anything approaches the speed of light it's time slows and at the speed of light time stands still. A implication of this is that photons do not experience the passage of time. if you hold your hand out and catch a photon from the sun every geek knows that that photon has taken eight and a quarter minutes to get here so the photon is eight and a quarter minutes old. To the photon however no time has passed. It experiences its whole life path as an instant. Its beginning is the same moment as its end. If you could ask a photon what it is it would not say it was a point it would say it was a line, or rather in fact I think it would experience space as two dimensional and it would say it was a point in a two dimensional picture that includes all space. The point is that the photon IS a point smeared along its life path.

So those two entangled particles in their (equally valid) view of the situation are in fact still touching when their probability wave collapses so communication IS possible.

What's wrong with that notion? Don't all speak at once.

cisco
QLD, 12323 posts
2 May 2010 11:44PM
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Rabbits, cows and horses all eat grass but they have different poop. So if you can't tell me why that is so, you don't know poop and I am not going to be bothered discussing quantum physics with you.

nebbian
WA, 6277 posts
2 May 2010 9:56PM
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So how does a photon view life if it's going through a prism as part of its journey?

That would make it slow down slightly wouldn't it?

And if it has slowed down then time would start to flow?

It's all to hard for me, quantum stuff just makes me think that the physics department might have raided the chemistry department's 'top shelf'.

NotWal
QLD, 7428 posts
2 May 2010 11:57PM
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NotWal said...
....
Don't all speak at once.


That means you Cisco

GalahOnTheBay
NSW, 4188 posts
3 May 2010 12:08AM
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We need a geek subforum - reading this stuff makes my (admittedly small) brain hurt! [}:)]

NotWal
QLD, 7428 posts
3 May 2010 12:17AM
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nebbian said...

So how does a photon view life if it's going through a prism as part of its journey?

That would make it slow down slightly wouldn't it?

And if it has slowed down then time would start to flow?

It's all too hard for me, quantum stuff just makes me think that the physics department might have raided the chemistry department's 'top shelf'.


Light speed is different in different media. I don't know if that means time is different in different media or that its just that particular speed that light travels at in a vacuum that is the boundary condition. If the second case is true then it follows that light would experience time flow in slower media as you say. Would that mean you couldn't have entangled particles in anything but a vacuum?

deXtrous
NSW, 451 posts
3 May 2010 1:48AM
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Are you referring to the infamous double slit experiment?

Here is a video which describes it beautifully.




NotWal
QLD, 7428 posts
3 May 2010 3:13AM
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No its not the famous double slit weirdness but that is a truly excellent illustration of it.

There seems to be a bunch of vids on you tube on the topic of quantum mechanics. I just watched an interesting snippet about quantum entanglement where the bloke proposed a theory that was not unlike what I was thinking. This arvo it occured to me that adding another dimension may explain it. As I proposed before, if the 2 entangled particles are really the same particle in their inertial frame but seen as 2 in my inertial frame then you need another dimension to account for the difference.

We have 3 dimensions of space and one of time and an additional dimension that qualifies the difference between all different inertial frames to eliminate paradoxes. I guess Lorentz transforms might usefully quantify it but I dont know.

The bloke on the vid proposed a similar thing but coming from another way. He proposed that the 2 entangled particles were really one hyper particle that manifests as 2 in 3 dimensional space. That's pretty much the same thing. It implies of course that everything is comprised of 3d manifestations of hyper particles. In other words another dimension is required to describe it.... curious. I wont let the fact that he goes on to implicate his theory with reincarnation put me off.

Trant
NSW, 601 posts
3 May 2010 11:56AM
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There might be some physicists who would like to know the answer too.
I think the famous phrase "If you think you understand quantum physics, then you don't understand quantum physics" applies, because it's all very unintuitive and weird.

Lawrence Krauss has given some accessible and interesting talks on cosmology which includes some quantum weirdness, my favourite is here



Every atom in your body came from a star that exploded. And the atoms in your left hand probably came from a different star than your right hand. It really is the most poetic thing I know about physics.

You are all stardust.

You couldn't be here if stars hadn't exploded. Because the elements, the carbon, nitrogen, oxygen, iron, all the things that matter for evolution weren't created at the beginning of time. They were created in the nuclear furnaces of stars. And the only way they could get into your body is if the stars were kind enough to explode.

So forget Jesus. The stars died so you could be here today.

NotWal
QLD, 7428 posts
3 May 2010 12:13PM
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Ah poetry. That's so romantic. Better than Joni Mitchell.

That was entertaining. What a great talker. I'll have to watch that again. Then I'll have to dig up some more Lawrence Krauss.

Thanks Trant. You made my day.

doggie
WA, 15849 posts
3 May 2010 11:54AM
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tobes said...

NotWal said...

Tobes' "Spooky action at a distance quantum weirdness headbands" got me thinking.



Another satisfied customer.


is mine in the post??

FlySurfer
NSW, 4453 posts
3 May 2010 2:05PM
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Relativity doesn't apply to quantum mechanics. I guess the easiest way for you to understand quantum entanglement is that it is basically the same object viewed from different locations.

There are scientist developing quantum communication devices... this would allow real time communication with our robotic explorers.

I suggest you consult Wikipedia.

tobes
NSW, 1000 posts
3 May 2010 6:33PM
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doggie said...
is mine in the post??


You ordered the Spooky Action At A Distance Headband doggie.
One of our staff is wearing that for you right now, you should be feeling all the beneficial energies of a Quantum Wierdness Headband TM.
All thanks to the unexplained magic of Quantum Entanglement.

I'd love to explain it for you NotWal, but it's a secret recipe, like Coke, KFC, you know, all the good stuff.
(and just between you and me, I think in the future, they'll be laughing about Quantum and String theory, like we laugh about Earth being centre of the universe)

Maybe the Large Hadron Collider can help?

doggie
WA, 15849 posts
3 May 2010 5:19PM
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tobes said...

doggie said...
is mine in the post??


You ordered the Spooky Action At A Distance Headband doggie.
One of our staff is wearing that for you right now, you should be feeling all the beneficial energies of a Quantum Wierdness Headband TM.
All thanks to the unexplained magic of Quantum Entanglement.

I'd love to explain it for you NotWal, but it's a secret recipe, like Coke, KFC, you know, all the good stuff.
(and just between you and me, I think in the future, they'll be laughing about Quantum and String theory, like we laugh about Earth being centre of the universe)

Maybe the Large Hadron Collider can help?


I can feel it!! Amazing...........................

theDoctor
NSW, 5779 posts
3 May 2010 8:11PM
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garyk
QLD, 277 posts
3 May 2010 10:03PM
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You all need to stop smoking the green

ginger pom
VIC, 1746 posts
3 May 2010 11:08PM
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NotWal said...

Tobes' "Spooky action at a distance quantum weirdness headbands" got me thinking. Some of you guys seem (I say seem) to know something about this.
Maybe you can help me.

As I understand it "action at a distance" is a phenomenon predicted by quantum mechanics and verified by experiment. It involves a pair of particles (say photons) produced by the same event (say a proton clobbers a neutron) and fly apart at light speed. They are said to be "entangled particles". If one of the photons is interacted with its "probability wave collapses" and it declares itself as a particle with a few fundamental properties any one of which (and only one) can be measured. At the same instant it's entangled pair particle will experience a similar "probability wave collapse" and declare itself in a complementary condition to its pair. The spooky thing about it (Albert Einstein's word) is that there is no way for one particle to communicate with the other. Relativity says instantaneous communication over any distance is impossible.

However Relativity also tells us that as anything approaches the speed of light it's time slows and at the speed of light time stands still. A implication of this is that photons do not experience the passage of time. if you hold your hand out and catch a photon from the sun every geek knows that that photon has taken eight and a quarter minutes to get here so the photon is eight and a quarter minutes old. To the photon however no time has passed. It experiences its whole life path as an instant. Its beginning is the same moment as its end. If you could ask a photon what it is it would not say it was a point it would say it was a line, or rather in fact I think it would experience space as two dimensional and it would say it was a point in a two dimensional picture that includes all space. The point is that the photon IS a point smeared along its life path.

So those two entangled particles in their (equally valid) view of the situation are in fact still touching when their probability wave collapses so communication IS possible.

What's wrong with that notion? Don't all speak at once.


Action at a distance is to do with whether common causes screen off.

Tutor at uni Mauricio Saurez wrote about this. I remember it being one of the more "accessible" lecture units...

http://www.springerlink.com/content/u7064031u060j6u0/

GreenPat
QLD, 4083 posts
4 May 2010 3:06PM
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NotWal said...


We have 3 dimensions of space and one of time and an additional dimension that qualifies the difference between all different inertial frames to eliminate paradoxes. I guess Lorentz transforms might usefully quantify it but I dont know.


If String Theory or M-Theory have anything to them there's more like 11 dimensions.

One of the blokes here wrote a 13 dimensional optimisation tool for a client a while back, which was a bit of a headstrain.

theDoctor
NSW, 5779 posts
4 May 2010 6:51PM
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then there's the whole time speeding up thing that the fringe quantum is talking about, as we move into a space which might be classed or seen as somewhat more enegetic A.T.M, but i guess for all youse with such a great handle on all things set in mainstream concrete, it would just be laughed off as conspiracy.

doggie
WA, 15849 posts
4 May 2010 5:16PM
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GreenPat said...

NotWal said...


We have 3 dimensions of space and one of time and an additional dimension that qualifies the difference between all different inertial frames to eliminate paradoxes. I guess Lorentz transforms might usefully quantify it but I dont know.


If String Theory or M-Theory have anything to them there's more like 11 dimensions.

One of the blokes here wrote a 13 dimensional optimisation tool for a client a while back, which was a bit of a headstrain.


Was that for a 13 dimensional TV? How cool

evlPanda
NSW, 9202 posts
4 May 2010 7:23PM
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What are the possible explanations for the instantaneous communication?

1) Something is travelling faster than light.
2) Space-time is warped ...for the two particles.
3) Extra dimensions (string theory)
4) ???

I'm always amazed that the objects being studied are being studied by something made up of the objects, i.e. us. That is spooky.

The whole speed of light/time thing I thought I got, but the explanation I had was the "spaceship accelerating, message from front of ship to back at one second interval but taking less than a second between intervals therefore time is faster on sending clock because can't travel faster than light" analogy...

... but i hijack your thread. Another time.

ginger pom
VIC, 1746 posts
4 May 2010 8:00PM
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evlPanda said...

What are the possible explanations for the instantaneous communication?

1) Something is travelling faster than light.
2) Space-time is warped ...for the two particles.
3) Extra dimensions (string theory)
4) ???

I'm always amazed that the objects being studied are being studied by something made up of the objects, i.e. us. That is spooky.

The whole speed of light/time thing I thought I got, but the explanation I had was the "spaceship accelerating, message from front of ship to back at one second interval but taking less than a second between intervals therefore time is faster on sending clock because can't travel faster than light" analogy...

... but i hijack your thread. Another time.



OR there isn't action at a distance... like I said. From the link I posted

"The status of causality in the EPR experiment has always been a source of controversy.
A condition of local causality is implicit in the original EPR criterion of
reality: “If, without in any way disturbing the system, we can predict with certainty
(i.e., with probability equal to unity) the value of a physical quantity, then there exists
an element of physical reality corresponding to this physical quantity.” In the
EPR set-up both systems have separated and are no longer interacting so it is assumed
that “no real change can take place in the second system in consequence
of anything that may be done to the first system” [1, p. 779]. The non-disturbance
clause in the antecedent is hence satisfied, and we may predictwith certainty the values
of properties in the distant wing. In other words: although the theory does not
represent causal influences, there seems prima facie to be physical determination of
values across a spatial gap. This notoriously led EPR to draw the conclusion that
the theory is incomplete; but in the aftermath of  Bell’s theorem it is customary to
draw the alternative conclusion – that there is non-local causation in nature."



evlPanda
NSW, 9202 posts
5 May 2010 12:37AM
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NotWal said...
It implies of course that everything is comprised of 3d manifestations of hyper particles.


A bit like steam condensing?

If I had the time I'd go back to uni and study. I'll read on with interest. Will take me ...some lifetimes to digest ginger pom's post.

ginger pom
VIC, 1746 posts
5 May 2010 9:32PM
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evlPanda said...

NotWal said...
It implies of course that everything is comprised of 3d manifestations of hyper particles.


A bit like steam condensing?

If I had the time I'd go back to uni and study. I'll read on with interest. Will take me ...some lifetimes to digest ginger pom's post.




I understood it before an I'm pretty sure I can understand it again. I'll just need to look it up.

It's something along the lines of common causes.

A and B are events. They occur together but are not caused by one another because they are both caused by C.

Eg
A = people playing cricket
B = people having barbecues
C = nice weather

It was something to do with C's probability to cause both A and B and whether if it does, they screen off ie C causes A but not B...

I'll try to find my notes but I think they're at my parent's house in the UK

NotWal
QLD, 7428 posts
6 May 2010 9:35PM
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FlySurfer said...

Relativity doesn't apply to quantum mechanics. I guess the easiest way for you to understand quantum entanglement is that it is basically the same object viewed from different locations.

There are scientist developing quantum communication devices... this would allow real time communication with our robotic explorers.

I suggest you consult Wikipedia.


I did read somewhere that the phenomenon can't be used for communication because there is no way to control or predict the state the particles will adopt. I guess that's the basis of the external causality notion that ginger pom mentioned. But the collapse is caused locally isn't it.



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"Quantum Weirdness !? (geek warning)" started by NotWal