Does instantaneous communication implies a preferrred Lorentz frame?

[heldervelez]

https://www.physicsforums.com/showpost.php?p=2439230&postcount=31" I' mentioned a cold start for the universe
I can defend that position, but I was not allowed to say how is it possible (because the post was closed).

In this scenario of cold start universe the 2nd law does not hold.
It appears to be valid only with a 'hot start'.

But instead of contend on the start of the universe let's look to the evolution of the universe:

back think 'homogeneous- no structure'
but a star has more structure than a cloud of..
a galaxy has more structure than a single star..
a cluser of galaxys has more structure than a single star..
a planet has more than...
life has more strucrure than anything else...
our brains has more ...
life was the last creation of the universe ...
all this happenings of crescent organization are aganst 2dn law..

 

[Dmitry67]

Life does not violate 2nd law...

 

[PTM19]

I prefer to be very careful with the entropy. As Landauer and Bennett have shown our intuitions can easily be wrong. For instance new entanglements in between the biological system and the environment are continuously generated (decoherence). So you have to consider the contribution of the entanglement entropy. This contribution is negative (entropy of the entangled systems is less).

So my answer to your 'certainly' would be: not necessarily.

Hydrolysis of ATP generates work and releases energy rising the temperature I don't think it's possible for entanglement to offset the associated increase in entropy. For that to work it would have to provide a substantial amount of negative entropy and the amount of entanglement would have to keep accumulating over time while I would say it roughly stays the same over time - as new entanglement is being generated it overwrites the old one.

 

[PTM19]

The evolution is not the evidence against the 2nd law - every biological process which produces order generates even more disorder in it's environment so life actually speeds up thermalization. In other words the exact same Universe as our own but one in which evolution and life never happened would have a *lower* entropy.

 

[Demystifier]

Dmitry67 and PTM19, it is not the question whether life itself is consistent with the second law. As you say, it is consistent.
The question is whether the EVOLUTION of life (in the Darwinian sense) is consistent with the second law. How evolution helps to increase the total entropy of the ecological system?

 

[Fredrik]

But instead of contend on the start of the universe let's look to the evolution of the universe:

back think 'homogeneous- no structure'
but a star has more structure than a cloud of..
a galaxy has more structure than a single star..
a cluser of galaxys has more structure than a single star..
a planet has more than...
life has more strucrure than anything else...
our brains has more ...
life was the last creation of the universe ...
all this happenings of crescent organization are aganst 2dn law..

You're saying that gravity pulling things together decreases entropy. That's not true. I don't know how to prove it, and I'm not going to discuss it any more than to say this, but there are other threads here on that topic. I suspect that you can find an explanation in one of them. If not, consider asking about it in a new thread.

 

[DrChinese]

https://www.physicsforums.com/showpost.php?p=2439230&postcount=31" I' mentioned a cold start for the universe
I can defend that position, but I was not allowed to say how is it possible (because the post was closed).

In this scenario of cold start universe the 2nd law does not hold.
It appears to be valid only with a 'hot start'.

But instead of contend on the start of the universe let's look to the evolution of the universe:

back think 'homogeneous- no structure'
but a star has more structure than a cloud of..
a galaxy has more structure than a single star..
a cluser of galaxys has more structure than a single star..
a planet has more than...
life has more strucrure than anything else...
our brains has more ...
life was the last creation of the universe ...
all this happenings of crescent organization are aganst 2dn law..

Isn't this fairly off topic?

 

[DougW]

That may be true, but I suspect that it's not that simple. If it's true, then it should be easy enough to write down a QM description of the sequence of events I described in #24 that makes it obvious that what you said is correct. I expect that the result would be the opposite, i.e. that if we tried to prove this, we would end up proving that the same paradox is present in the MWI too. I haven't tried to do this yet. Maybe I'll give it a shot later.

I believe that MWI would eliminate the possibility of superluminal communication before the experiment ever gets underway. Remember, the theory that superluminal communication exists is derived from entanglement in the first place, and MWI would argue that there were always multiple sets of entangled particles, and that by measuring one particle, no 'message' is sent to the second particle at all, but the observer (who is local to the observation, and bound by lightspeed in receiving the results of the measurement) is instantaneously 'split' from the 'multiple' worlds where the measurement of both particles could be one of several values into a 'single' world where both entangled particles 'have always had' the measured value. So without the entanglement argument to suggest superluminal communication, you'd either have to abandon the experiment or carry it through with lightspeed as the maximum velocity for both the communication and any other actions...

 

[dmtr]

I prefer to be very careful with the entropy. As Landauer and Bennett have shown our intuitions can easily be wrong. For instance new entanglements in between the biological system and the environment are continuously generated (decoherence). So you have to consider the contribution of the entanglement entropy. This contribution is negative (entropy of the entangled systems is less).

So my answer to your 'certainly' would be: not necessarily.

Hydrolysis of ATP generates work and releases energy rising the temperature I don't think it's possible for entanglement to offset the associated increase in entropy. For that to work it would have to provide a substantial amount of negative entropy and the amount of entanglement would have to keep accumulating over time while I would say it roughly stays the same over time - as new entanglement is being generated it overwrites the old one.

I would think it do accumulate over time. New entanglements are generated (i.e. ATP generates work and releases energy -> coupling with the environment -> decoherence = new entanglements with the environment). Old entanglements don't go away, they get more and more diluted in the environment, but the entanglement of the system with the environment is not being reversed.

Considering that decoherence involves a lot of entanglements, and the environment is continuously increasing in size (light cone) I wouldn't be surprised if the corresponding entanglement entropy contribution is substantial and keep accumulating over time.

 

[DrChinese]

I believe that MWI would eliminate the possibility of superluminal communication before the experiment ever gets underway. Remember, the theory that superluminal communication exists is derived from entanglement in the first place,...

Welcome to PhysicsForums!

The Bohmian class of theories started as early as the late 1920's with some work by de Broglie, so I don't think that you could really say that superluminal concepts were derived from entanglement per se. Everett started his work on MWI well before Bell's Theorem, as did Bohm.

You will find a lot of threads here about MWI and other interpretations of Quantum Mechanics. Generally, we distinguish orthodox QM (oQM), Many Worlds (MWI), Bohmian Mechanics (BM or dBB) as interpretations which are isomorphic in their physical predictions. (Obviously, if they could be tested they would.) So you shouldn't feel the need to defend your favorite interpretation at every turn - although all of us tend to do that from time to time anyway!

 

[thehangedman]

So you shouldn't feel the need to defend your favorite interpretation at every turn - although all of us tend to do that from time to time anyway!

Yeah and I know some even take the stance that the whole argument is irrelevant, so long as the predictions are accurate. To me this whole issue, and even the wave-particle duality issue etc, boils down to making careful assumptions and applications of what we know. To me it never was a great mystery about Schroedinger's Cat, or in this case "instantaneous communication". The reality is, the entire universe is one giant closed system, meaning its only ever an approximation to treat any two things as "separate". In the case of the entangled particles, we have our minds twisted because we want to think of them as two separate particles, living separate lives. But, the reality is, they are interconnected. No "communication" is actually even happening here. No photons are exchanged. We are just a few scientists looking at the state of the system. Like the guy who opens the box to see if Schroedinger's cat is dead or alive.

The wave form collapses because it only ever was a mathematical construct from the get go. Something built by us to represent the state of the system, and what we knew about the system. Once we open the box, what we know changes, and hence the wave form collapses. Nothing mystical. We don't need to "exchange particles" with the cat's waveform to collapse it, we just have to "know". It collapses because "what we know" is built into what it is by definition.

 

[Fredrik]

Remember, the theory that superluminal communication exists is derived from entanglement in the first place,

Post #1 in this thread mentioned entanglement as a reason to suspect the existence of superluminal influences, but those "influences" would only directly affect unobservables, so they can't be used to send superluminal messages. Therefore, entanglement doesn't really have any relevance to the paradox I've been talking about. This paradox arises when we consider the possibility of easily detectable tachyons. By "easily detectable" I mean that the time to detect a particle doesn't grow at least linearly with the distance they've traveled. (If it did, the paradox would be avoided. See my posts earlier in this thread). By "tachyons", I mean particles corresponding to m^2<0 irreducible representations of the proper orthochronous Poincaré group. (In special relativistic QM, the particle species correspond to different irreducible representations (see chapter 2 of Weinberg's QFT book). The ones with m^2<0 are tachyons).

and MWI would argue that there were always multiple sets of entangled particles, and that by measuring one particle, no 'message' is sent to the second particle at all,

I agree with this.

 

[PTM19]

Dmitry67 and PTM19, it is not the question whether life itself is consistent with the second law. As you say, it is consistent.
The question is whether the EVOLUTION of life (in the Darwinian sense) is consistent with the second law. How evolution helps to increase the total entropy of the ecological system?

Well, to me this way of stating the problem does not make much sense, it's a bit like asking whether by parking cars in an orderly fashion we can break the 2nd law of thermodynamics. The law is only concerned with molecular motions and if the law holds on this level then it holds no matter what happens higher in the hierarchy of complexity. When a car's engine is running it keeps increasing entropy and how it is driven or parked doesn't matter.

I would say the same holds for evolution which is a high level process to which physical entropy has no direct application. Life obeys the 2nd law on the molecular level and evolution is just a complex activity of life forms. Yes, it makes those life forms more complex over time but that doesn't mean it somehow decreases entropy on the molecular level. A particular protein operates in the exact same way whether it is part of a bacteria or a human so here the fact that humans are "more evolved" doesn't matter. The only meaningful difference on the molecular level is that humans contain more complex biomolecules but when those biomolecules are being constructed the additional decrease in entropy associated with this extra molecular order is offset by extra energy being released during their construction. So from the point of view of entropy the only effect of evolution is that the cost of life in terms of entropy keeps rising.

 

[Dmitry67]

I agree.
2nd law does not say that EVERYTHING EVERYWHERE becomes more and more chaotic. Life just breaks the symmetry creating less chaotic systems by the cost of more chaotic environment.

In any case, our planet is receiving huge amount of negentropy from Sun, as we see 1 hot spot in one place and dark sky around. Earth returns thermal radiations, spread almost evenly in all directions. Life just uses that flux of negentropy. That negentropy is what we get from Sun! Not the *energy* - because Earth emits excatly the same amount of energy into space as it receives from Sun. So there is no surprise that the life started from the plants, not from animals: plants could absord the negentropy directly, while animals - only indirectly.

Think about the Photosynthesis: contrary to C + 02 -> C02 (burning), photosynthes *consumes* energy, not releases it. Why did Nature used it? because of negentropy from Sun.

 

[Demystifier]

Well, to me this way of stating the problem does not make much sense, it's a bit like asking whether by parking cars in an orderly fashion we can break the 2nd law of thermodynamics. The law is only concerned with molecular motions and if the law holds on this level then it holds no matter what happens higher in the hierarchy of complexity. When a car's engine is running it keeps increasing entropy and how it is driven or parked doesn't matter.

From the phenomenological point of view, you are absolutely right.
However, I am not satisfied with this explanation from the theoretical point of view. Namely, the second law valid on the thermodynamical level is DERIVED from the ASSUMPTION that system allways evolves towards a more probable state. But if this assumption is valid at ALL levels, not only on the molecular level, then cars should also obey this law. But they apparently don't. The question is - why? Why the assumption above is valid on the molecular level, but not on the macroscopic (car) level?

 

[Demystifier]

In any case, our planet is receiving huge amount of negentropy from Sun, as we see 1 hot spot in one place and dark sky around. Earth returns thermal radiations, spread almost evenly in all directions. Life just uses that flux of negentropy. That negentropy is what we get from Sun! Not the *energy* - because Earth emits excatly the same amount of energy into space as it receives from Sun. So there is no surprise that the life started from the plants, not from animals: plants could absord the negentropy directly, while animals - only indirectly.

Think about the Photosynthesis: contrary to C + 02 -> C02 (burning), photosynthes *consumes* energy, not releases it. Why did Nature used it? because of negentropy from Sun.

That's all true, but the chemistry of life does not explain INTELLIGENCE. It is intelligence (of humans, apes, birds, ...) that can change nature in a manner that seems to violate the natural evolution towards more chaotic states.

 

[Demystifier]

For those who are lost and don't see what second law has to do with instantaneous influences, here is a brief recapitulation:
instantaneous message -> message backwards in time -> causality -> flow of time -> arrow of time -> second law
So, it has very much to do with it. It's not offtopic at all.

 

[Dmitry67]

That's all true, but the chemistry of life does not explain INTELLIGENCE. It is intelligence (of humans, apes, birds, ...) that can change nature in a manner that seems to violate the natural evolution towards more chaotic states.

It depends on what we call 'chaotic'
Dead and void universe has less entropy then universe with life.

In our everyday life we call an absense of order a 'chaos'
But it not exactly what is meant by the 2nd law
Perfect Order (low entropy states) are aways DEAD, they can't evolve and think because they are always primitive - they have only few states.

So the more intelligent beings MUST be more chaotic (must have more internal states)

 

[Demystifier]

As a sort of summary of this thread, I have written a dialog containing all mayor objections and the corresponding responses. I attach it as a PDF below.

Additional comments, questions, objections, etc. are wellcome.

 

[Dmitry67]

Looks very good!
It would be interesting to extend this logic, however, to Closed Time-Like loops.
Because the argument:

R: Stop, don’t even bother with the details! It cannot work because a machine is a
macroscopic classical object, and I have already explained that superluminal signals do
not work at the macroscopic classical level.

Does not work there because macroscopic objects are affected by the CTL as well. But may be it is an offtopic.

 

[Demystifier]

Yes, it would be offtopic.

 

[T-Boone]

Other than the MWI, I have never heard of cause/effect time travel paradoxes disappearing in the absence of free will? The "will" portion of the thought experiment is required for the paradox to occur. You receive a valuable antique pocket watch from a strange older man on your 12th birthday...On your 50th birthday you develop a time machine and go back to your 12th birthday and give your younger self the watch. Where did the watch come from originally?

Also, wouldn't backwards time travel allow you to know with 100% certainty both the momentum & location of an electron?

 

[Dmitry67]

check this
http://en.wikipedia.org/wiki/Novikov_self-consistency_principle

 

[T-Boone]

check this
http://en.wikipedia.org/wiki/Novikov_self-consistency_principle

I am familiar with the Novikov principal, but I think that it's not very good because it doesn't really say anything other than the obvious and so it can be considered a tautology. It goes something like this:

"IF time travel is possible, then paradoxes cannot arise from it."

That's all well good but then again, paradoxes cannot arise from anything to begin with! So you could replace the "if" part with whatever you'd like and it's still true. Again, really says nothing other than paradoxes cannot arise. One could however say, that time travel is impossible because it CAN lead to a paradox. Of course, we are talking about time travel to the past.

Also, Novikov doesn't apply to the MWI (Many Worlds Interpretation) because it assumes a singular timeline whereas MWI does not. However, I really don't like MWI because I find it too outlandish & fantastical; it is based on assumption on top of conjecture on top of speculation on top of...poppycock! But it is in vogue now-a-days so I guess there's something to be said for that; but, technically, MWI doesn't really allow for time travel either! But that's a whole other story.

 

[Descartz2000]

I am not a physicist or a neuroscientist, however I have read quite a bit on free-will. It seems whether or not true free-will does occur is an ongoing debate. There is much research indicating that true free-will is an illusion, that is: the ability to make choices without the parameters of previous or current influences (biology, genes, brain function, past experiences, etc). If we look at Libet's studies from the past, and current neuroscience that dare dip into the 'untestable' concepts of free-will, we see that actions within the brain occur initially in an unconscious part and then trickle down into conscious states. When we become aware of these states we conclude that we made a 'free-choice'. Based on these experiments, it seems logical to conclude that free-will is an illusion. Check it out, it seems that brain scientists are able to determine that a subject makes a decision before the subject himself is aware that a decision is actually made. I am not sure how this relates to free choice experiments, but I bet it plays a significant role.

 

[WaveJumper]

Other than the MWI, I have never heard of cause/effect time travel paradoxes disappearing in the absence of free will?

Abscence of free-will is the same as "reality is an illusion". In an anti-realist setting, all paradoxes disappear.
BTW, there is absolutely no way there'd ever be free will, if time travel were possible.

The "will" portion of the thought experiment is required for the paradox to occur. You receive a valuable antique pocket watch from a strange older man on your 12th birthday...On your 50th birthday you develop a time machine and go back to your 12th birthday and give your younger self the watch. Where did the watch come from originally?

Where did the universe come from originally? These kind of causal questions must end somewhere or your neurons will sizzle and fry.

Also, wouldn't backwards time travel allow you to know with 100% certainty both the momentum & location of an electron?

Yes, that's why there'd never be backwards time-travel as depicted in sci-fi movies.

 

[T-Boone]

Descartz2000, I find the free-will & time travel debate quite interesting as well. Like most good debates, the outcomes really depend on the definitions being used. In other words, how you define free will or how you define time will greatly affect the outcome of the debate.

I for one do believe in free will and that backwards time travel is not possible.

 

[T-Boone]

WaveJumper,
I think that the anti-realist point with respect to physics, is really quite pointless as it denies objective reality; the very framework where physics occurs. It can be a good philosophical endeavor to expand your mind and maybe help you think outside the box, but I can't see it meld at all with physics.

As far as your question is concerned (i.e. where the Universe came from) it came from a singularity at the beginning of time: an initial uncaused state from whence the Big Bang emerged. No sizzle & fry here, I assure you! )

And I also agree with you on the fact that backwards time travel is not possible. I'll even go as far as saying that the concept of "backwards time travel" is itself a paradox!

 

[WaveJumper]

WaveJumper,
I think that the anti-realist point with respect to physics, is really quite pointless as it denies objective reality; the very framework where physics occurs. It can be a good philosophical endeavor to expand your mind and maybe help you think outside the box, but I can't see it meld at all with physics.

Non-realism, in the sense of objective reality being very different to the true reality is not at all pointless for physics. In fact, it's the only way forward.

As far as your question is concerned (i.e. where the Universe came from) it came from a singularity at the beginning of time: an initial uncaused state from whence the Big Bang emerged. No sizzle & fry here, I assure you! )

Good for you! I imagine it must feel good to not doubt scientific interpretations, trends and assumptions.

 

[T-Boone]

Non-realism, in the sense of objective reality being very different to the true reality is not at all pointless for physics. In fact, it's the only way forward.

True reality? As opposed to what, fake reality? Objective reality = true reality = what is used in physics.

Good for you! I imagine it must feel good to not doubt scientific interpretations, trends and assumptions.

Did you read anything of what I wrote previously?

However, I really don't like MWI because it find it too outlandish & fantastical; it is based on assumption on top of conjecture on top of speculation on top of...poppycock! But it is in vogue now-a-days so I guess there's something to be said for that; but, technically, MWI doesn't really allow for time travel either!

Sounds like I am doubting & even challenging scientific interpretations, trends and assumptions, don't you think? As far as the Big Bang explanation goes, I was just trying to illustrate that your question (i.e. where did the universe come from originally) could be answered without any sizzling and frying of neurons.