73 réponses à ce sujet

[Lord_Tirian]

vhatever wrote...

Huh?  how does something move "faster than light" without traveling at all?  He even used it as a argument how the instantaneous nature being described  "is not possible". And I quote: "QE cannot transmit information faster than the speed of light". And it's competely wrong.  Heisenberg is a reference to his uncertainty principle. That should be obvious.

Erm, whaaaa... ?

First, nobody ever said anything *physical* was moving around, but if point A and point B communication, *something* goes from A to B, namely information - and that's what is problematic, information travelling faster than the speed of light (which really means transmitting something from A to B in less time than a light ray takes to travel from A to , as this screws causality.

Furthermore, he did not use it as his main argument why quantum entanglement cannot allow transmission of information - the collapse is random, leaving both ends with random noise (that's, however, exactly oppsite, i.e. A would for example get 0110010101, then B would get 1001101010, so B would know what A measured... but it's still random jibberish).

And for your "Heisenberg Uncertainty Sphere", I was not asking about the uncertainty principle, but what exactly this sphere is supposed to be... (by the way, in your comparision with magnetic fields... you know that magnetic fields only propagate with the speed of light, right?) - not to mention that it's not the Uncertainty Principle that's governing QE.

Modifié par Lord_Tirian, 10 avril 2010 - 11:33 .

[vhatever]

Other than saying "it's magic", there is no proper analogy for QE in physics. A field(ormultiple fields) of uncertainty are the best analogy one can give to make it even remotely understanable to someone who clearly has a pretty weak grasp of physcis, despite pretending otheriwse.



And information IS physical -- it's real. It must be, or it's nothing. hence if it moved faster than light, it's traveling. The end. Your pathetic attempt to parse words is a complete failure.

[Jonas TM]

I was under the impression that an entangled particle pair occupied the same reference frame, which would negate the causality.

[Lord_Tirian]

vhatever wrote...

Other than saying "it's magic", there is no proper analogy for QE in physics. A field(ormultiple fields) of uncertainty are the best analogy one can give to make it even remotely understanable to someone who clearly has a pretty weak grasp of physcis, despite pretending otheriwse.

You just made the "field of uncertainty" up.

vhatever wrote...

And information IS physical -- it's real. It must be, or it's nothing. hence if it moved faster than light, it's traveling. The end.

That's exactly the point - there is no information transmitted by QE!

Jonas TM wrote...

I was under the impression that an
entangled particle pair occupied the same reference frame, which would
negate the causality.

Problem with that is that it's created in the same inertial frame, but you can take one and give it some speed. Then they're moving relative to each other which makes pretty clear that they're not in the same inertial frame any longer.

Modifié par Lord_Tirian, 10 avril 2010 - 11:50 .

[vhatever]

Yes, I did make it up. That's why I said "think of it LIKE". It's the only way to explain things to people like you who don't know what they are talking about, unfortunately. Arguing there is no "information being trasmitted" is completely semantical argument. If soomeone was looking for a murder in some neighborhood, and they were told "the suspect is not white", would you qualify that as "information"? I sure would. Now the semenatics of "transnmit" is a tar baby, that I'm not getting pulled into.

[WarAxe7]

WhiteRobes wrote...

Actually,
Quantum Entanglement as stated in Mass Effect is wrong.
Quantum Entanglement cannot transmit information faster than the speed of light. That would be a violation of the theory of relativity. All we know that the states of the two particles are entangled.
It's sort of like you cut a coin in the middle, giving you a side with heads and a side with tails. Then you separate them, without knowing what they are.
Sort of like pack them into a box each, and then separate the boxes. When someone opens the box, when they see a tails, they know the other box contains a heads. But you cannot influence the fact that the other person will have heads or tails, that is a random occurrence.
For Further reading.
http://plato.stanfor...entries/qt-epr/
http://plato.stanfor...es/qt-entangle/

Also, to clear up a few issues,
Einstein, Poldosky and Rosen did NOT do experiments, they presented the EPR argument [about entanglement] as a proof of the incompleteness of Quantum Theory. In 1962, John Stewart Bell showed that if Quantum Mechanics is true, then the EPR argument has some fundamentally counterintuitive consequences, which can be experimentally determined. This experiment was first done by Alain Aspect in circa. 1970, and showed that Quantum Mechanics is right.
Secondly, No Entanglement has nothing to do with multiple universes or anything of that sort. It is a simple fact of quantum mechanics, which does not require nor is better explained by calling upon Everett's interpretation. [Which is, to most physicist, quite useless]

Whiterobes, you are getting QE confused with Quantum Superposition (ala Schrodinger's Cat and all that).  One of the insane things about QE is, yes, it implies imformation could travel FTL.  Breaks the "rule"... but hey, it IS quantum.

And you're right about the big bang... nothing to do with quantum entanglement.  Although, since it's brought up, that is ANOTHER instance of information (well, really EVERYTHING) travelling FTL.  During the first moments of the BB there was a brief hyper-inflationary period... and THAT led to the Type I multiverse we have now.  

Modifié par WarAxe7, 10 avril 2010 - 11:59 .

[WarAxe7]

And I have a degree in Nuclear Engineering, BTW. I'd be more interested in what other educated folk here think. Not so much those who are merely sci-fi geeks.

[Jonas TM]

Ah, the only argument I have to that and it could very well be flawed is theoretical. Assuming the current theories of wormholes are at least partially valid. The ends may be separated by vast distances and relative motion, but they occupy the same reference frame. Now that is an area of distorted space time, not an actual particle that has mass so the rules may not apply. But that to me would seem to be information travelling faster than the speed of light.

[WarAxe7]

Jonas TM wrote...

Ah, the only argument I have to that and it could very well be flawed is theoretical. Assuming the current theories of wormholes are at least partially valid. The ends may be separated by vast distances and relative motion, but they occupy the same reference frame. Now that is an area of distorted space time, not an actual particle that has mass so the rules may not apply. But that to me would seem to be information travelling faster than the speed of light.

I think in terms of wormholes or any other form of warped space you aren't technically breaking the FTL rule because instead you are making the apparent huge distances travelled much shorter by curving space.

The entangled state is really something altogether spooky.  We don't understand it, and we sure haven't been able to do anything useful with it yet... it's just goobledygook inside sceintists' heads.  :-)

Additionally, I'm skeptical that quantum computers will coming around anytime soon.

Modifié par WarAxe7, 11 avril 2010 - 12:12 .

[Lord_Tirian]

vhatever wrote...

Arguing there is no "information being trasmitted" is completely semantical argument.

Wait, are you talking about classical or quantum information? My concern here is mainly whether it's possible to transfer classical information through a quantum entangled pair of particles - so far, there's no possible mechanism to do so.

If you're talking about quantum information, then, yes, absolutely, both particles are in contact (as they form a single system with one definite state anyway).

[Nostradamoose]

I hate physics and how the macro doesn't fit the micro. Why can't anything be simple...?

[vhatever]

Nostradamoose wrote...

I hate physics and how the macro doesn't fit the micro. Why can't anything be simple...?

Blame your lying eyes.

Heh.

[Vaenier]

They use mass effect fields to alter the particles, thus making quantum entanglement transmitting data possible. Duh...

[Nostradamoose]

vhatever wrote...

Nostradamoose wrote...

I hate physics and how the macro doesn't fit the micro. Why can't anything be simple...?

Blame your lying eyes.

Heh.

I'll go blind myself right away.

[Ziggy]

[quote]WarAxe7 wrote...

And I have a degree in Nuclear Engineering, BTW. I'd be more interested in what other educated folk here think. Not so much those who are merely sci-fi geeks.[/quote]

[/quote]

I think whiterobes is on the right track but Lord_Tirian really knows this stuff.
From my physics lectures the slightly more technical explanation of QE is something like this:
Once the particles have interacted they will thereafter be described by an entangled wavefunction and are 'connected' by it no matter how far apart they travel. By measuring one of one of them their common wavefunction collapses and the second one instantly has the corresponding property.

But like Lord_Tirian said, this wavefunction is just a probability wave so it's not possible to know what state you'll find the particle in when you measure it so it can't be used to transmit information.

Modifié par Em23, 11 avril 2010 - 12:51 .

[vhatever]

Em23 wrote...

WarAxe7 wrote...

And I have a degree in Nuclear Engineering, BTW. I'd be more interested in what other educated folk here think. Not so much those who are merely sci-fi geeks.

I think whiterobes is on the right track but Lord_Tirian really knows this stuff.
From my physics lectures the slightly more technical explanation of QE is something like this:
Once the particles have interacted they will thereafter be described by an entangled wavefunction and are 'connected' by it no matter how far apart they travel. By measuring one of one of them their common wavefunction collapses and the second one instantly has the corresponding property.

But like Lord_Tirian said, this wavefunction is just a probability wave so it's not possible to know what state you'll find the particle in when you measure it so it can't be used to transmit information.

Wrong.

Modifié par vhatever, 11 avril 2010 - 01:21 .

[Ziggy]

vhatever wrote...

Em23 wrote...

WarAxe7 wrote...

And I have a degree in Nuclear Engineering, BTW. I'd be more interested in what other educated folk here think. Not so much those who are merely sci-fi geeks.

I think whiterobes is on the right track but Lord_Tirian really knows this stuff.
From my physics lectures the slightly more technical explanation of QE is something like this:
Once the particles have interacted they will thereafter be described by an entangled wavefunction and are 'connected' by it no matter how far apart they travel. By measuring one of one of them their common wavefunction collapses and the second one instantly has the corresponding property.

But like Lord_Tirian said, this wavefunction is just a probability wave so it's not possible to know what state you'll find the particle in when you measure it so it can't be used to transmit information.

Wrong.

Could you elaborate?

Modifié par Em23, 11 avril 2010 - 01:22 .

[Corehaven22]

I love these kinds of conversations. ( sarcasm )



The internet never fails to amaze me. Somehow, the people here seem to know more than Einstein. Everyone is a brilliant Quantum Physicist on the internet. You people do know you'll never really reach any kind of reasonable conclusion here.



Some of you are acting as though you actually KNOW all of the angles pertaining to these theories and issues. Since most of the science resides in theory, and of course hasnt been fully tested and explored, we couldnt POSSIBLY know what capabilities Entangled Quantum Particles could employ.



Oh but we think we do dont we...... \\facepalm



Im sure we'll revolutionize science right here on the freggin Mass Effect game forums. Yes. Please do continue on your scientific rants. You're all so darn smart. I am in awe.

[MisterMonkeyBanana]

WhiteRobes wrote...

Actually,
Quantum Entanglement as stated in Mass Effect is wrong.
Quantum Entanglement cannot transmit information faster than the speed of light. That would be a violation of the theory of relativity. All we know that the states of the two particles are entangled.

Then again, EDI might have just fudged her answer so that Shepard can understand it. Afterall s/he is an Alliance Marine and if they were Earthborn at least, probably didn't get a great education.

It does make me instantly think "Damnit, I'm a Spectre not a physicist!" however.

[vhatever]

Information is transmitted. See heisenberg's uncertainty principle. It's debatable the usefulness of such information, however, and in order to actually "gain" the information by a second observer, the rate will be slowed down to the maximum speed of light.

[cindercatz]

I don't have a physics degree, but that's basically a "road not taken" for me (so far) out of financial constraints and competing personal aspirations (I'm an art & science guy, not one or the other). I guess I'm a 'real science geek', so I hope you guys don't hold that against me.

I don't see why information reproduced using entangled pairs (in sufficient numbers) couldn't work for FTL communication. If the state of entangled particle A and particle B (or particle Ab) are the same, the information being communicated doesn't have to travel in any way apart from the effect of that information on particle A. Reading particle B (assuming a uniform language is assigned to the particles' state in the same way that language is assigned to computer on/off data now), you could simply reproduce the information on the recieving end. Even if you had a pair that maintained opposite states, you'd simply factor that into the fabrication of the original data on the "recieving" end. The speed of communication then becomes the processing speed of the fabricator rather than the speed other information can travel from one position of the entangled pair to the other. Thoughts?

Modifié par cindercatz, 11 avril 2010 - 05:29 .

[abstractwhiz]

It's a little difficult to talk about quantum entanglement, because it involves assigning a physical interpretation to a mathematical result. You can't argue with the mathematics, but figuring out how it maps to physical reality is not straightforward, especially in the quantum realm where nature mercilessly mocks human intuition. It's easier to just "shut up and calculate", as the physicists say.  

I understand this is largely how theoretical physicists operate these days - find a mathematical formulation that explains the data you see, and then worry about interpreting it afterwards. Experimental results can be predicted either way, so testing the theory is not impaired, merely human understanding.

Disclaimer: I'm a computer scientist, not a physicist, and most of what I know comes out of an introductory quantum computing class that left me somewhat unsatisfied. But I can back up the mathematical view of things with an example - we first encountered entanglement in class when some derivation involving a two particle system produced (|01> + |10>)/sqrt(2), and the professor pointed out that you couldn't factor this, while something like (|00> + |01>)/sqrt(2) turns into |0> (|0> + |1>)/sqrt(2). (The notation may feel a bit odd, but you can just read it as normal algebra for the purposes of the example, if you think of | > as a sort of strange pair of brackets.)

This is what entanglement is all about. In the latter case, you can slice it into two pieces, and that gives you the state of each particle, independent of the other. The former case admits of no such decomposition. One particle cannot be described without the other, and picking one state automatically fixes the other. 

Now, if you ask what mechanism mediates this in reality, I have no idea. I'm not going to waste time looking like an idiot by speculating about things I know nothing about, but which someone else might really know something about. 

Modifié par abstractwhiz, 11 avril 2010 - 05:43 .

[abstractwhiz]

In one of my favorite scifi novels (Charles Stross's Singularity Sky), quantum entanglement is used for long-distance communication in ways similar to Mass Effect, but there is no true FTL propagation of information. For example, suppose a colony planet needs to speak with the homeworld. One of the two planets generates a large number of entangled pairs, and then flies one half of them to the other planet using normal (slower than light) travel. Once this has been done, the two planets can communicate 'instantaneously' by tweaking the bits on their end. 

I'm not certain, but I believe this mode of communication escapes violating relativity on a technicality - if the person you want to talk to is 10 light years away, you're going to have to wait at least 10 years from the time you entangle those bits before you can start talking. Not sure, though - I don't know enough physics to write down the equations, which is ultimately what it all comes down to. 

I don't know how this works in the ME universe, where FTL travel is possible and you can move those entangled qubits 10 light years in a day or so. 

[cindercatz]

That's pretty much exactly what I was thinking (the novel's scenario, might have to find that sometime. ) On the math, if I get you right, we're actually splitting the equation to make sense of our interpretation of the observed whole state after the fact, but I do remember reading about the same experiment somebody mentioned earlier in the thread where an entangled pair was separated and the particle state remained true, so to speak, between the pair. So I wonder if they truly observed and interpreted for each end, or if they interpreted for the pair and split the equation again. If that's what's happening, then I imagine we'd have to be able to determine whole states from observing individual sides of the equation that don't make sense unless we extrapolate out what the whole state would be, right? I wonder if we know whether it's true that we can accurately describe the state of each entangled side by always splitting the whole equation evenly or not?

I hope I don't come across as totally lost.. lol