Author Topic: Almost an ansible? entanglement without classical particles or EM Comms  (Read 42217 times)

Offline QuantumG

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More so, every time someone comes up with a mathematical trick that appears to allow violation of causality, speed of light, conservations of energy/charge/etc, it always turns out that the effect can't be used to do so. Every single frickin' time. At some point you have to accept what the universe is telling you.

Ahh.. the feeling of every generation that they've learnt all there is to learn.
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Offline KelvinZero

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The point should not be taken that instantaneous communication is impossible. The important point is that it isn't even defined what it means. Of course blah blah blah may be possible but that conversation can't hold my interest very long.

Someone mentioned many worlds before and I dismissed it but I might not have understood what they meant. I did actually come up with a many worlds-like idea a while ago. You could be communicating with alternate possibilities. For example suppose you had an infinitely powerful super computer at your location that sucked in every possible piece of information available at light speed and used this to extrapolate a possible future at a distant location, arbitrarily defined as 'now'. It would still be limited. It could not predict a cosmic-ray particle travelling towards you near lightspeed for example. If your ansible communication contained this sort of uncertainty then it would not violate relativity and more importantly we could consider what we actually had.

Offline Stormbringer

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I feel this might be slightly related so I'll put it here and then give my reasoning:

http://phys.org/news/2015-04-unparticles-path-superconductivity.html

and a slightly different particle thing but i have my reasons:

http://phys.org/news/2015-04-supercomputer-lambda-baryon-quark-molecule.html

Now, if i understand the first article properly the component particles of an unparticle actually have mass individually but that when acting together they are massless. That's   ...interesting. So by putting massive particles together in the right configuration they act as if they are massless? Massless things can go really fast.

I would not mind some commentary on that.

Now the second article: a lambda Baryon is a regular baryon with a kaon appended to  the nucleon. Kaons normally go poof in a tiny tiny fraction of a second or something like that. This includes Kaonium pairs. But Kaons are stable if appended to other particles? or not? I think they may be. Does anyone see if it gives a decay time for lambda baryons?

Anyway if they are stable, in this case inside a baryon, does that mean that if there is an aggregation of them they might also be stable in and of themselves? A neutron is only stable in a nucleus unless they are squeezed together in a neutron star. A nucleus composed only of kaons or similar particles would be tinier than a regular atom and have stronger nuclear and electronic bonding.

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Offline JasonAW3

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What gets me is simple;  If a communications could be transmitted in real timeto another person lightyears away, with no lag time, (Other than the speed of sound going from the sender to the transmitter and then from the receiver to the person listening, how would that be a violation of Relativity?

So long as the reception of the message cannot arrive before it is received, where is the paradox?

     If data can be shared by entangled particles, again, so long as simultunaity is maintained between two points, where is the paradox?  (Yeah, it's a word I made up, I think, it means for an event to happen at two remote locations at the same time, as compared to each location's frame of reference).

     Mind you, this could not be applicable to objects moving at relativistic velocities, as the frame of reference would be massively skewed.  While data transmitted to an object moving at relativistic velocities would be vastly spead up, data transmitted from an object moving at relativistic velocities should be slowed down, relative to the temporal difference in reference frames.
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Offline Mark K

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What gets me is simple;  If a communications could be transmitted in real time to another person light years away, with no lag time, (Other than the speed of sound going from the sender to the transmitter and then from the receiver to the person listening, how would that be a violation of Relativity?

So long as the reception of the message cannot arrive before it is (sent? added here) received, where is the paradox?


 You cannot send a message faster than light from one location to another that has space like curve between them without some (indefinite maybe infinite number of) frames of reference having the receipt occur before the sending. This is s standard problem of superluminal signalling in Special Relativity.

It is unavoidable from the way space and time are defined in S.R. I am pretty sure it was Robert Forward who had several articles that gave relatively humorous details of several of these situations, but I can't find any references now.

Offline Nilof

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What gets me is simple;  If a communications could be transmitted in real timeto another person lightyears away, with no lag time, (Other than the speed of sound going from the sender to the transmitter and then from the receiver to the person listening, how would that be a violation of Relativity?

So long as the reception of the message cannot arrive before it is received, where is the paradox?

     If data can be shared by entangled particles, again, so long as simultunaity is maintained between two points, where is the paradox?  (Yeah, it's a word I made up, I think, it means for an event to happen at two remote locations at the same time, as compared to each location's frame of reference).

     Mind you, this could not be applicable to objects moving at relativistic velocities, as the frame of reference would be massively skewed.  While data transmitted to an object moving at relativistic velocities would be vastly spead up, data transmitted from an object moving at relativistic velocities should be slowed down, relative to the temporal difference in reference frames.

The violation is in the "no lag time" part, which is ill-defined because of relativity of simultaneity. If there is no special frame of reference, you would be able to do it in a different frame, where "before" and "after" is not the same as in the first frame.

Furthermore, there is the more fundamental fact that in any frame of reference, the time coordinate is a human convention(much like say, the z-coordinate in any spatial coordinate system) and only the proper time is a truly "natural" quantity. In general relativity it is a fundamentally flawed way to define simultaneity because time dilation happens not just because of speed but also because of gravitational gradients. This is why the GPS system needs to incorporate general relativity so that your phone won't tell you that your position is 15 km below Denver.

The only truly natural way to "sync up" the two ends that would be well-defined even in GR is to require that they are created in the same point, and have the ends synced up by the proper time that passes along their worldlines from the point where they were created. In that case you could construct something like the twins paradox where you could send one end on a spaceship back and forth at relativistic speeds and have one slow down relative to the other to construct a time machine.

This kind of synchronization is what happens to wormholes. In this particular case, there are possible mechanisms to prevent acausality, such as Hawking's chronology protection conjecture which states that wormholes in an acausal setup automatically collapse preventing time travel. That is, assuming wormholes actually exist.
« Last Edit: 04/08/2015 02:49 PM by Nilof »
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline Stormbringer

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The funny thing is even if Hawking's *conjecture* is true; it does not prevent all time travel. Not by itself anyway.

The following is what people such as Dr John Kramer, Dr Woodward, Paul Davies are on record as having said about wormholes, time travel/causality issues related to wormholes, Cosmic back Reaction and Dr Hawking's conjecture:

 If you can get a wormhole set up between here and a distal destination you can travel into the future and (in a limited but still interesting and useful way) into the past. You just cannot go to a time before the wormhole was set up. Also; the feedback mechanisms intended to prevent any traversible wormhole at all actually end up providing the way to set up such a wormhole. Cosmic Back Reaction provides a means to enlarge, propel and steer wormholes when it was intended to collapse the wormhole before any naughty messing about with time travel could occur. CBR does not kick into full wormhole killing gear unless you set up a wormhole network in such a way that it could be used to travel into the past beyond the point when the wormhole was activated.
« Last Edit: 04/08/2015 12:00 AM by Stormbringer »
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Offline RonM

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I understand relativity of simultaneity and the statement that there is not a special frame of reference. However, what would constitute a special frame of reference? If it is something that can be measured from any frame of reference, then isn't the cosmic microwave background leftover from the Big Bang a special frame of reference? If I am missing something here, please enlighten me.

Offline ChrisWilson68

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I think we are in trouble if our scientific analysis consists of "This violates some fudged principle created to make physicists feel better about the universe on philosophical grounds."

Fortunately, causality isn't "some fudged principle created to make physicists feel better about the universe".

The only people fudging here to make themselves feel better about the universe are those who want to believe faster-than-light travel or communication is possible in spite of all the very strong evidence that it is not.

Sure, we could find new evidence one day that calls into question whether FTL travel or communication is possible.  So far, there's been no such evidence.

There is absolutely no evidence of which I am aware that any of these postulates about preserving order have any basis in physical facts let alone that they are universally true.

Every experiment, everywhere, has supported the idea that causality has a basis in physical fact.  Everyday life experience also provides such evidence.  I can't think of anything at all that has more evidence going for it than causality.

Furthermore physicists will evoke time travel when convenient. Feynman and wheeler posited advanced waves and retarded waves traveling into the future and the past to solve certain otherwise intractible problems.

You're misunderstanding what they were talking about.  Those theories were explicitly consistent with the inability to communicate classical information or travel faster than light.

Recent entanglement experiments strongly supported future measurements affecting the state of particles that had already ceased to exist.

And that has absolutely nothing to do with violating causality.

Relativity allows (so far) limited time travel but it is time travel. all of it allowed by the rules; given a traversible wormhole which is not yet ruled out.

There are lots of things that are consistent with relativity but inconsistent with other evidence.  Relativity only describes part of known physics.

Relativity allows it; physicists have *faith* however that something in Quantum Gravity theory which hasn't been discovered yet will forbid that.

That's utter nonsense.  Physicists follow the evidence.  Causality is overwhelmingly supported by the evidence we currently have.  That's why physicists coming up with theories try to find theories that also support causality -- because a physical theory that matches the evidence is better than one that doesn't match the evidence.

*Faith* that some how "theory X" will forbid it. LOL. Better get out the robes, incense and ritual fetishes.

EDIT: Unless i am mistaken any relativistic travel allows time travel and we have observed physical objects with mass that are traveling at relativistic speed with our astronomical instruments. Certain celestial objects that got booted by a massive gravitational partner at some point. If one of these objects were to return to it's starting point at speed it would amount to time travel.

No, it wouldn't amount to time travel.  You seem to misunderstand the word "relativitstic" or its implications.  Going faster than light would amount to time travel.  The word "relativistic" means, roughly, "close to but less than the speed of light".
« Last Edit: 04/08/2015 05:31 AM by ChrisWilson68 »

Offline ChrisWilson68

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I understand relativity of simultaneity and the statement that there is not a special frame of reference. However, what would constitute a special frame of reference? If it is something that can be measured from any frame of reference, then isn't the cosmic microwave background leftover from the Big Bang a special frame of reference? If I am missing something here, please enlighten me.

A "special frame of reference" would mean your communication system only works in some special frame of reference, not in all the other frames of reference.  So far, all evidence says there is no special frame of reference, meaning laws of physics all work in all frames of reference.

Lets say you have a device that allows you "instant" communication from point A to point B.  "instant" in what frame of reference?  If relativity is right and physics is the same in all frames of reference, then your communication device should work in any frame of reference, and it should allow communication both from point A to point B and from point B to point A.

Events that are simultaneous in one frame of reference are not simultaneous in another frame of reference if they happen at different points in space.  If the points are 1 light hour apart in frame F1, events that are up to one hour apart at points A and B in frame F1 will be simultaneous in some other frame F2.  So, if you can communicate simultaneously in frame F2, you can send a message from point A to point B that is half an hour in the past in F1 but simultaneous in frame F2.  Then, send the message back one minute later from point B to point A using instant communication in F1 and it arrives at point A 29 minutes before it was sent from point A.

Offline Nilof

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I understand relativity of simultaneity and the statement that there is not a special frame of reference. However, what would constitute a special frame of reference? If it is something that can be measured from any frame of reference, then isn't the cosmic microwave background leftover from the Big Bang a special frame of reference? If I am missing something here, please enlighten me.

In the more general sense of general relativity, a reference frame is just any set of coordinates describing spacetime, which are allowed to be curvilinear or to describe an accelerating or rotating background.

Since coordinates are just a human convention, general relativity is invariant under general coordinate transformations. Effectively this means that trying to define a "global time" naturally is doomed to failure because nature doesn't care about whether humans have an easy time describing it.

If there are no closed timelike curves, you can introduce a partial time ordering: if there is a timelike geodesic from A to B, A objectively happens before B. But events with a spacelike separation will generally be causally unrelated and you cannot say whether one or the other happens first.
« Last Edit: 04/08/2015 12:04 PM by Nilof »
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline Stormbringer

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I think we are in trouble if our scientific analysis consists of "This violates some fudged principle created to make physicists feel better about the universe on philosophical grounds."

Fortunately, causality isn't "some fudged principle created to make physicists feel better about the universe".

The only people fudging here to make themselves feel better about the universe are those who want to believe faster-than-light travel or communication is possible in spite of all the very strong evidence that it is not.

Sure, we could find new evidence one day that calls into question whether FTL travel or communication is possible.  So far, there's been no such evidence.

There is absolutely no evidence of which I am aware that any of these postulates about preserving order have any basis in physical facts let alone that they are universally true.

Every experiment, everywhere, has supported the idea that causality has a basis in physical fact.  Everyday life experience also provides such evidence.  I can't think of anything at all that has more evidence going for it than causality.

Furthermore physicists will evoke time travel when convenient. Feynman and wheeler posited advanced waves and retarded waves traveling into the future and the past to solve certain otherwise intractible problems.

You're misunderstanding what they were talking about.  Those theories were explicitly consistent with the inability to communicate classical information or travel faster than light.

Recent entanglement experiments strongly supported future measurements affecting the state of particles that had already ceased to exist.

And that has absolutely nothing to do with violating causality.

Relativity allows (so far) limited time travel but it is time travel. all of it allowed by the rules; given a traversible wormhole which is not yet ruled out.

There are lots of things that are consistent with relativity but inconsistent with other evidence.  Relativity only describes part of known physics.

Relativity allows it; physicists have *faith* however that something in Quantum Gravity theory which hasn't been discovered yet will forbid that.

That's utter nonsense.  Physicists follow the evidence.  Causality is overwhelmingly supported by the evidence we currently have.  That's why physicists coming up with theories try to find theories that also support causality -- because a physical theory that matches the evidence is better than one that doesn't match the evidence.

*Faith* that some how "theory X" will forbid it. LOL. Better get out the robes, incense and ritual fetishes.

EDIT: Unless i am mistaken any relativistic travel allows time travel and we have observed physical objects with mass that are traveling at relativistic speed with our astronomical instruments. Certain celestial objects that got booted by a massive gravitational partner at some point. If one of these objects were to return to it's starting point at speed it would amount to time travel.

No, it wouldn't amount to time travel.  You seem to misunderstand the word "relativitstic" or its implications.  Going faster than light would amount to time travel.  The word "relativistic" means, roughly, "close to but less than the speed of light".
No- i know well what these terms mean. And merely relativistic travel is also time travel due to gamma factor. if i go to a distant star at 99.99 percent C i travel in time. I experience an abbreviated time compared to observers at home. in my perspective the trip takes mere moments or weeks at worst. That is time travel. It's not your definition of time travel; but it is time travel.

If i return home at 99.99 percent light speed; I will have aged moments or weeks at worst while everyone I greet at journey's end will be about 9 or ten years older. I will have effectively traveled to the future skipping all the inconvenient things in between moments.
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Offline RonM

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Thanks ChrisWilson68 and Nilof for your replies on my special frame of reference question. Now I understand it.

Offline JasonAW3

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Information cannot exceed C; wavefronts may do so, but can't carry information.

We're trying to use English here to describe subtle mathematics, and our innate perception of causality etc interferes with any understanding of the outer universe - we are simply one of the Great Apes, looking out into a Universe which doesn't fit in with our mental predispositions, and attempting to erect a narrative.

Go and read Jastrow.

Explain quantum tunneling then.

     A particle going from point A to point B without transitioning through the interveining space certainly seems to violate the concept of information traveling faster than light.

     Admittedly this, so far, has only been observed on the nanoscopic scale, but the transition certainly SEEMS to be happining at faster than light velocities.
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Offline gospacex

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I think we are in trouble if our scientific analysis consists of "This violates some fudged principle created to make physicists feel better about the universe on philosophical grounds."

It's not just philosophical grounds. Allowing time travel would mean that if you travel back in time and try to kill yourself, there will be a force, distinct from normal physical laws, which will not let you do that. You try to shoot yourself, but your gun doesn't fire. Or bullet swerves away. I can see why this is seen as absurd. Local physics can't possibly depend on whether you came from the future or not.

Still, people are not censoring FTL theories. It is okay to research them; but any theory which postulates that FTL is possible needs to explain how paradoxes are avoided.

Offline QuantumG

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I love the way causality is sacred but universality of time is whatever. We are products of our era. Both relativity and quantum mechanics (and, heck, the accelerating expansion of the universe and just about everything else in modern physics) are so adverse to common sense that we should not be surprised if causality is the next casualty.
 
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Offline Nilof

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There is nothing special about requiring extraordinary claims to have extraordinary evidence. Self-consistent non-causal universes have been studied to great lengths and it certainly isn't "taboo" to mention them.

They are just spectacularly different from everything we have observed so far and the existence of a CTC explicitly kills off most of thermodynamics and information theory. For a computer next to a CTC you don't just have P = NP, you in fact have something even stronger than P = PSPACE as all computation becomes memory limited only.

Information cannot exceed C; wavefronts may do so, but can't carry information.

We're trying to use English here to describe subtle mathematics, and our innate perception of causality etc interferes with any understanding of the outer universe - we are simply one of the Great Apes, looking out into a Universe which doesn't fit in with our mental predispositions, and attempting to erect a narrative.

Go and read Jastrow.

Explain quantum tunneling then.

     A particle going from point A to point B without transitioning through the interveining space certainly seems to violate the concept of information traveling faster than light.

     Admittedly this, so far, has only been observed on the nanoscopic scale, but the transition certainly SEEMS to be happining at faster than light velocities.

Tunneling does not lead to any kind of FTL travel. Anything that has the Dirac equation or quantum electrodynamics at the bottom will trivially be causal. Any other result is a result of miscalculation or the improper use of some approximation.

There are lots of phenomena that can make it look like you are moving something faster than the speed of light in physics, but as you explain what is happening in terms of more fundamental physics it turns out that you can't ever transmit any information faster than light with it and that the apparently "FTL" component is allowed.

I like to use constructions in cellular automata like as an analogy. In that example, it looks like an LWSS has been moved faster than the "speed of light" in Conway's game of life, but when you accept that all patterns in cellular automata are just a collection of cells it becomes obvious that you can't actually transmit information that way. Similarly, any patterns in physics are just excitations in fields rather than what we intuitively think of as "particles" and the rules that govern these trump any illusions you may encounter at a higher level of abstraction.
« Last Edit: 04/08/2015 10:31 PM by Nilof »
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline Stormbringer

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I have a question on unparticles related to Classical electrodynamics, QED and the Standard Model.

My understanding of an unparticle is that it is an aggregate of positive mass particles which acting as a group sums it's mass to zero.

In the above mentioned frameworks as i understand them normal massed particles sum to a slightly positive mass but the sources side of the equation included a large negative mass component or else divergence cannot be eliminated. In the above frame works the various source contributors to electron mass such as magnetic moment dipole moment angular velocity self gravity and so forth overcome the negative bare mass with a slight over balance turning particle mass positive.

well then you have the unparticle where the positive mass is overcame by just enough something to sum out to zero. So what is it? Negative bare mass enlarged? positive contributor reduced? additional negative energy above the component level in the field section of the equations? what mechanism allows for the zero mass property? because you know... this is not supposed to happen.

and if you can sum positive masses to zero mass what stops you from summing to a negative mass with some other configuration in the unparticle?

 
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Offline KelvinZero

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Explain quantum tunneling then.

     A particle going from point A to point B without transitioning through the interveining space certainly seems to violate the concept of information traveling faster than light.

     Admittedly this, so far, has only been observed on the nanoscopic scale, but the transition certainly SEEMS to be happining at faster than light velocities.
I sure can't explain quantum tunnelling :)

..but the physicists who claim to understand it say that the mathematics that predict quantum tunnelling also explain why it cannot be used to transfer information faster than light.

Sure, that is sort of like an appeal to authority. But you really have to accept both statements together. Either "There is this thing called quantum tunnelling but it does not let information travel faster than light, because that is what the mathematics says", or "Commonly accepted quantum mechanics is analysed by thousands of doofuses with PhDs and implemented by thousands of doofus engineers who just can't spot the obvious thing we can spot without much experience with quantum mechanics." :)

Offline ChrisWilson68

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EDIT: Unless i am mistaken any relativistic travel allows time travel and we have observed physical objects with mass that are traveling at relativistic speed with our astronomical instruments. Certain celestial objects that got booted by a massive gravitational partner at some point. If one of these objects were to return to it's starting point at speed it would amount to time travel.

No, it wouldn't amount to time travel.  You seem to misunderstand the word "relativitstic" or its implications.  Going faster than light would amount to time travel.  The word "relativistic" means, roughly, "close to but less than the speed of light".
No- i know well what these terms mean. And merely relativistic travel is also time travel due to gamma factor. if i go to a distant star at 99.99 percent C i travel in time. I experience an abbreviated time compared to observers at home. in my perspective the trip takes mere moments or weeks at worst. That is time travel. It's not your definition of time travel; but it is time travel.

If i return home at 99.99 percent light speed; I will have aged moments or weeks at worst while everyone I greet at journey's end will be about 9 or ten years older. I will have effectively traveled to the future skipping all the inconvenient things in between moments.

OK, then you're just making up your own definition for a term that already has a very widely understood meaning.  What's the point of that other than deliberate miscommunication?

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