General relativity, we are told, breaks down at the smallest scales, but does it necessarily hold good on a cosmic scale.

Non-local correlations can exist over cosmic distances and require collapse of the wave function to occur over such distances simultaneously with the measurement. At a minimum the notion of simultaneity requires a synchronous coordinate system for spacetime.

This does not sit well with relativity which militates against the concept of an absolute time frame.

This is one of the weird things about quantum theory (QT). Quantum entanglement has been experimentally verified, so there is no question that it happens. There have been 3 suggested explanations for how it happens. None of the 3 is particularly probable, but experiments have been performed that invalidate all 3 individually. Last year an experiment was performed that invalidated 2 of them at the same time. But it is highly improbable that the remaining one is true, especially since it has been invalidated by itself. People are still working on it and hope to come up with an experiment that invalidates all 3 explanations at the same time.

In 1935 Albert Einstein, Podolsky, and Rosen wrote a paper (the EPR paper) about entanglement in which they explained it away using one of the 3 explanations. The EPR paper has become a very highly cited paper in QT. In the 1960s somebody showed that that explanation was not satisfactory, so that explanation is no longer considered valid. Einstein himself didn't like entanglement, calling it "Spooky action at a distance". But quantum theory calls for it and in the 1970s the first experimental proof was found.

Yes it is a bit of a problem. It does seem to require communication between the entangled particles that is faster than light speed. As far as I know there is no theoretical explanation of how it works, other than the fact that QT calls for it. It is just one of those things about QT that will drive you crazy if you really try to comprehend it.

I have a pretty good book about entanglement "The Dance of the Photons" by Anton Zeilinger The book was written in German, and was translated into English last year.

Bill Gill

Bill, from the little I know of Zeilinger's book I suspect that it is very different from the general run of P S books. Would you recommend it to a non-scientist?

Yes, I would. "The Dance of the Photons" is not highly technical, but I think it gives a pretty good overview of quantum entanglement for the average person who has just a little knowledge of QT. The thing I most like about it is that it concentrates mostly on quantum entanglement, rather than trying to cover the whole field of QT. I suppose somebody who has never heard anything about it might have a problem, but from your posts I think you would have no problem. Now that I have said that I will say that not everything he said made perfect sense to me. I will have to reread it when I get it back from my daughter. Of course the first time I read something I usually wind up not catching on to everything in it.

Bill

Thanks, Bill. I have quite a large pile of books to work through, and somewhat limited time, but if/when I get round to this one I have no doubt there will be bits that don't make sense to me. As long as they are not the same bits that don't make sense to you, we may be able to help each other out.

The war between Einstein and QT. Haha. It's so interesting to know how QT wronged and how Einstein wronged.

I am not sure too many buy the waveform collapse interpretation much anymore Bill S. You have to be a real die hard QM zealot to believe it to many problems with experiment observations.

OK, but something seems to happen over a distance, so the situation remains much the same.

Correct .. now remember our pesky attempt to kill QM information ... so we can start to add in some of the background.

The nasty part is GR is at odds with how you need to close it which is interesting as Hawking found out.

Results from LHC will be out Tuesday can't wait to see what it has to say ... I am still backing no stinking Higgs :-)

Explain, please.

The background is called the limits of uncertainy under QM.

A full discussion was published for New Scientist Magazine here is the copy (http://www.hermanusastronomy.co.za/wp-content/uploads/Uncertainty-untangled-June-2011-newsletter.doc)



It is for that reason we say with certainy that there are limits to what you can do with Quantum Information.

An attempt to delete quantum information it will change time as seen by the delayed-choice quantum eraser or it will change space position as seen by entanglement energy transportation.

Hence we say with certainty Quantum Information can not be created nor destroyed only changed from one form to another within our physical world.

Does this law sound familar .. a variant goes by the name of the 1st law of thermodynamics?

Perhaps you need us to demonstrate a Quantum Bomb to make you believe as Einstein had to for E=MC2 to be accepted :-)

Hey we have made a start its called a bose-nova (http://en.wikipedia.org/wiki/Bosenova).

I always loved Weiman's comment


Hey we blew them to another time or another location but there around somewhere we just don't know where :-)

So yes Quantum Information can really blow you up!!!!!

To re-phrase the question in the OP: Does QT imply non-relative simultaneity?

I am not sure the question is actually valid for QM there is "no 3D space" in the quantum world thats why two entangled entities react simultaneously no matter how far apart you take them.

Relative in the way you are using them I take it means "relative space"????

The problem stems back to that problem of trying to resolve QM into classic physics the interpretation is always flawed at some point which is what we have spent 100 years studying and failing.

The bosenova explosion (http://en.wikipedia.org/wiki/Bosenova) really cemented how different a world QM is. Up until that moment many refused to think of QM information as real or important when it can rip matter apart and create energy from seemingly nowhere and classic physics can't explain it you really have a massive problem with classic physics.

Since then bosenova explosions have been studied and studied because classic physics has no way to explain it

http://www.nist.gov/public_affairs/releases/bosenova.cfm
http://physics.aps.org/articles/v1/13
http://physicsworld.com/cws/article/news/35556
http://www.physorg.com/news171188983.html

Funny while I was looking up what bosenova data was actually on the net I ran across this ... quite funny or not depends on your take.

http://blogs.nature.com/news/2008/09/scare_story_firefighting_a_wor.html

Can you say a bit more about this for the benefit of those of us who need to be spoon-fed?

Quantum Mechanics is all about evolution of time when you break it down (http://en.wikipedia.org/wiki/Time_evolution)

It is the change of state brought about by the passage of time that is why it is described in terms of wave equations or probability.

So when I talk about a sine wave or tossing head/tails I don't need to describe a 3D space I am describing and arbitary space and an outcome waveform or probability even in these basic examples.

Classic mechanics deals with 3D world of physical stuff but what is time in this world it is an abstract thing. Why does time go one way .. as Brian Greene would say ... why do you see eggs fall and break but you never see broken eggs jump up of the floor and form a full egg. There is no way under classic physics to explain time and it's direction you basically have to accept it just is.

There is an equally important law in classic physics that is seldom discussed called Newtons 3rd law. It is seldom discussed becasue it is what many call a trivial or deduced law. Most do not realize there entire view of the world revolves around this trivial law that has no proof it is an observational law. It is also the most misunderstood law of physics .... http://en.wikipedia.org/wiki/Reaction_(physics)

The most important part of the 3rd law is actually that a body at rest will stay at rest. You don't see things get up and move without the application of a force and that force will be opposed.

So lets look at the classic physics pillars that have no explaination you just have to accept

- Energy can not be created nor destroyed only converted to other forms
- Time has direction and just is
- Newtons 3rd law
- Entropy


Quantum mechanics can provide answers to each of those

- Quantum information can not be created nor destroyed only converted from one form to another.
- Time describes the progression of the state transitions in a quantum system
- Quantum systems to be stable must have a ground state (http://en.wikipedia.org/wiki/Ground_state)
- Having a ground state imparts an entropic gradient


Do you see why we say the two great physics systems need to merge and why current QM physicists think it is unlikely QM will be rolled into classic physics.

So we move onto virtual partciles (http://en.wikipedia.org/wiki/Virtual_particle)



So we can now have virtual partciles which are borrowing energy because they exist for only a described time in an explict waveform and the space domain is of no consequence to them.


So if we have got you through all that you are now at the current QM point which says the universe is a quantum mechanical system the physical 3D space is a projectivism in which we experience this QM system.


So what does the QM universe really look like ... thats anybody's guess QM really has nothing to say about it at all. It could be like our real world with stuff hiding in the gaps like string theory says or we could be a complete hologram. QM systems demand no shape or space thats a demand of classic physics.


Thats my bad english attempt to give a layman's view Bill S. It's very touchie feely and light on detail but you can either read or ask if you need areas filled in with more background. I have avoided trying to give a particular QM story because obviously there are different views of what the QM universe looks like.

And if we got you through all that we can next discuss Quantum Discord (http://en.wikipedia.org/wiki/Quantum_discord). Sometimes QM doesn't need such a weird world after all :-)

Okay so above as Bill S wanted we discussed how and why many QM theorists thinks GR should be bought in under it.

The argument goes we have spent 100 years and countless small fortunes and brilliant minds and none could merge QM in GR. Infact the last great hope Mr Hawkings has officially given up
(http://www.newscientist.com/blogs/cultur...everything.html)

String theory and SUSY look in deep trouble with LHC findings classicality has a crisis.

So it's time to look seriously at the reverse.

The problem is the QM world is very messy as we discussed above because it really doesn't care for structure which as humans we tend to care very much about.

So enter the half way house we call Quantum Discord (http://en.wikipedia.org/wiki/Quantum_discord).

The argument goes QM needs no physical structure classic physics wants structure so let them both co-exist simultaneously on top of each other.

This is a very very new interpretation (birtdate 2001) and hence we represent the system as two sets of entropy because that is the big common between the two systems



This half way house is probably the last bastion of our hope for some degree of classical physics to survive if this falls we really are in the deep end with a full QM universe.

So are there any results that support the halfway house model.

Well there are tentative yes results

http://www.physorg.com/news/2011-08-quantum-entanglement.html
http://www.physorg.com/news/2011-08-entanglement-macroscopic-dissipation.html

For the more technical of you there is a presentation discussion that might interest you
http://qols.ph.ic.ac.uk/qi_ims/slides/slides_2010_08_10.pdf
http://www.physics.utoronto.ca/~alqasimi/talks/QES.pdf
http://arxiv.org/ftp/arxiv/papers/1106/1106.5097.pdf

Orac, I looked through your first reply to Bill S. I must say that I didn't pick up on everything you said, but one thing I think I got out of it is that QM is about the evolution of states with time, but you don't think classical physics is. Classical physics does incorporate evolution with time. After all calculating the orbit of a planet around the Sun certainly depends on time. And in GR Einstein developed a system that implicitly includes time as a part of the system (SpaceTime).

Now GR doesn't work when you come down to the atomic level, even at the level of many atoms. But QM doesn't work at all well when you come up to the level of solar systems. Trying to calculate the orbit of a planet from a QM perspective would be pretty much impossible.

So I figure that trying to get to GR from QM is going to be enormously difficult, if not impossible. But the problem is just as bad trying to go the other way. We need something different that will wind up incorporating both GR and QM.

Bill Gill

The interesting thing about GR Bill is remember we have a spacetime loaf. So GR involves time but it's a static backdrop there is no evolution involved infact time is a quite static thing in GR. Thats one of the problems of visualizing it in the GR backdrop.

Could it not be equally true to say it is change brought about by physical processes, such as those designated by the laws of thermodynamics, and that time is simply an arbritrary measure of that change? This would seem particularly appropriate if we are dispensing with the concept of spacetime.



How can virtual particles be said to exist hey are if not in space?

You could but thermodynamic processes can go both ways as can all classical physics so now you have a directionality issue ... that is I can reverse a thermodynamic or classic process so if I do that I can take time backwards.

Time has a arrow of direction ... why?



Strict QM says they don't exist in space ... thats the point ... what you see is an illusion.

You "see" a rainbow but most people accept that it is an illussion bought about by certain conditions yet it has a definite visual shape and form and you can even photograph it.

From the photograph I could if I want measure it in many ways length, height, colour, intensity but what I am measuring is an illussion.

That it is appears to occopy a space and form in our speak but it actually represents a vastly different process to what it appears to us as. In some ways it is why rainbows have fascinated humans for a very long time.

We actaully do another version of the same distortion we get the students to walk up onto a platform and measure the height of a line from the platform floor to whatever accuracy they can. They dutifully do it and you ask them are you absolutely certain about your measurement there is no way you could be wrong. Some will realize they are about to be gotcha'ed most will say they are certain. At that point we cut the power to the platform which is actually a steel plate sitting on high frequency actuator.

See the human body can't sense the high frequency movement and you cant see it so what they think is the floor is actually the top of the stroke of the actuator. When you cut the power the actuator sinks back 2 inches (50mm). Everyone is actually out by that ammount in there measurement no matter how careful they were.

It's a very visual illustration that measuring something requires you to know what your references for the measurement are. Now think about a world with QM and measuring anything.

I have absolutely no chance of figuring out the math involved in GR, but I am aware that time is intimately involved in all GR calculations. Since time varies in all gravitational and accelerated frames I can't see that time is static (no evolution) in any GR calculations. In fact as things move in a GR field they are constantly changing their relationships to one another and therefore any change is accompanied by a time change.

And just as a quick real world example of how QM and GR are kind of separated, but both real, consider the Global Positioning System (GPS). The GPS satellites run almost completely on QM principles, from the solid state electronics in them to the atomic clocks they use to provide exact locations to receivers on the ground. But if you used only the QM principles the GPS wouldn't work. You have to include a GR gravitational correction to the clocks, because they are at a different gravitational potential from the ground stations and receivers.

Granted GR and QM don't work together in many areas, but neither one applies in all cases. QM works great in areas where gravity is predominant and GR works great in areas where other forces are predominant.

As far as I know the only place in which QM addresses gravity is that it does acknowledge a graviton as the carrier of the gravitational force. But there is, as far as I know, no good theoretical way to incorporate the graviton into the overall QM world.

Bill Gill

Bill, you seem to be saying that static time rules out evolution. If you are standing still, and time is flowing past you, any changes you make constitute evolution in time. Because motion is relative; it must also be true that if you are moving through static time you must be able to observe no differences in the outcomes of your actions. Your evolution in time is the same in both cases. What is there in GR calculations that would make this untrue?

Does this differ from saying "we have an arrow of direction through time"?

I was referring to Orac's statement that time is a quite static thing in GR. I interpreted this to mean that GR calculations are made without regard to time. That would mean that time was not evolving, just passing. In GR time is a component of spacetime and therefore any changes in space also produce a change in time. As I understand it this is really the heart of GR, that there is no separation between time and space.

Bill Gill

No Bill G what I am explaining is in GR time and space form spacetime they can't evolve they are a static spacetime loaf.

Lets put it in reference from translation from the horses mouth so to speak




So under GR there are actually two sorts of time

1.) The one you see

non-relativistic time is the observable quantity measured (or approximated) by physical clocks, in general relativity clocks measure s along their worldline

2.) GR's version t


EXPLICITLY

In general relativity, there isn’t a preferred and observable quantity that plays the role of independent parameter of the evolution, as there is in non-relativistic mechanics. General relativity describes the relative evolution of observable quantities, not the evolution of quantities as functions of a preferred one

With general relativity we have understood that the Newtonian “big clock” ticking away the “true universal time” is not there.

As I said GR can't deal with evolution of time for there is not master clock in GR it actually explicity says so.

It's the same as it has no zero space reference frame.

I think there is a typo there and I'm not sure what the sentence means. What you meant to say is probably quite clear, but I got lost trying to parse that sentence. Could you correct it?

Bill Gill

LOL yeah did I really write that .. must have been daydreaming

There is no non-inertial or zero frame for space which is the same as Newtonian absolute space frame.

Does that make sense now :-)

Wasn't really that important you go the important part in GR time is an abstract arbitrary thing. You can coincident it your local concept of time but GR doesn't really care about your time hence that sort of evolving time is not part of GR.

Getting back to the original problem now contrast that to QM, it needs a definite absolute version of time. Thats what leads to bells inequality and all the dramas.

Imagine entangle a particle take one of the partciles and accelerate it so GR/SR time changes all hell breaks loose for QM. Think of a particle near the event horizon of a black hole huge problem for QM.

The moment you accept QM stuff is real its not just a fancy mathematical description, time as seen between GR and QM definitions is a HUGE deal.

BTW if we got you to that point Bill here is the next obvious step. Entangle two partciles and we start changing the QM information of it at a known period. Now take one of the entangled particles and accelerate it very fast.
Now does the QM change occur simulataneously for both particles and if it does this means the accelerating particle can now act a reference clock to the original frame ... is it possible :-)

Ah! That makes much more sense. Don't feel too bad about writing something without knowing what it is. I have done it many times. And trying to proof read your own writing is difficult.

I'm afraid that the quotes you give are rather beyond me. I have never taken any physics or math courses beyond the undergraduate courses I had in college over 30 years ago. What I do know is based more on descriptive texts than mathematical texts. Sometimes I can kind of follow along with more mathematical discussions if the descriptive text is good enough.

Now to the discussion. I agree that in GR there is no universal reference frame against which to measure anything. But in the observer's reference frame you can measure what is happening in all other reference frames around you. So as things move around space and time are both evolving, with respect to the observer. So in GR there is nothing that is static. That is why GR has been successful in predicting the evolution of the universe.

Part of the problem with the mismatch between QM and GR is that GR is actually concerned almost entirely with one force, gravity. QM of course has almost no interface with gravity, since it is so weak that at the energies at which particles interact it has no influence on the interactions.

I certainly agree that your example of accelerated bound states would produce some major problems. That is one of the areas where there can be big problems in a comparison between GR and QM. But as we look at the universe it is obvious that GR gives wonderful results, and as we look at particles QM gives wonderful results. Just trying to figure out how to make them mesh gives a lot of people head aches. So for the time being I accept that both of them are completely true, but don't try to figure out what the comparison is. I will wait for somebody a lot more highly trained to come up with some sort of answer.

Bill Gill