QM/GR Wrong about Nature of Time?

[rogerl]

Lee Smolin stated in Trouble with Physics (page 256):

"More and more, I have the feeling that quantum theory and general relativity are both deeply wrong about the nature of time. It is not enough to combine them."

<snip>

"We have to find a way to unfreeze time - to represent time without turning it into space. I have no idea how to do this. I can't conceive of a mathematics that doesn't represent a world as if it were frozen in eternity. It's terribly hard to represent time, and that's why there's a good chance that this representation is the missing piece."

-----
What is he talking about? Anyone got an idea, or share new papers or perhaps have a clue to an eventual solution?

 

[atyy]

http://arxiv.org/abs/0909.1861
http://arxiv.org/abs/1011.5754

 

[Phrak]

http://arxiv.org/abs/0909.1861

Good grief, atty. Have you read what this guy from the "Perimeter Institute for Theoretical Physics" has written?

 

[atyy]

Good grief, atty. Have you read what this guy from the "Perimeter Institute for Theoretical Physics" has written?

Hmmm, ist it bad? I have to confess I like her work.

 

[rexrino]

Perhaps time is real in the sense that inches are real or millimeters are real.

 

[tom.stoer]

I have no clear picture about it, but my impression is that physical time emerges as a "clock defined by physical processes". In a universe w/o any physical process there is no physical time, only a collection of time coordinates w/o any physical relevance. Not even proper time of particles is meaningful as nothing happens to this particle. Think about a photon world line, you can rescale it as you like.

A simple physical process would be the decay of a particle. In this case the proper time begins to make sense as one can use the decay time or half-life as a standard clock to measure or to compare other processes. Think about two decaying particles with different half-life

So the idea is that the web of physical processes is the basis on which physical time emerges. In that sense this physical time will not be a fundamental entity but will emergy only in certain scenarios. Therefore there is no reason to be worried about the fact that there is no such physical time in certain quantum gravity approaches. It simply does not make sense to look for time at that level. In the same sense one could ask (better: should not ask) "what is the color of an electron?".

 

[Fra]

What is he talking about? Anyone got an idea, or share new papers or perhaps have a clue to an eventual solution?

I don't know exactly where in the book that is but I think he is talking about the fact that the timeless notions implies eternal timeless laws, and this does not make sense from the inferentical perspective. Ie. there is no process finite in time, where you can infer thta the laws of nature are not evolving. Ie. the notion of timeless law does clash with an inferential perspective you expect from measurment theory.

Except in one special case - where you study subsystem of the universe. Here time does dissappear simply because it's easier to extract asymptotic behaviour.

Just try to explain, how a finite observer, by a finite process is to infer from experiment that the laws are eternal. Obviously that's not possible in any sensible way. So that mere concept is due to an illusion induced by the success of this when describing subsystems.

See

"On the reality of time and the evolution of laws"
-- http://pirsa.org/08100049

"Laws and time in cosmology"
-- http://pirsa.org/10050053/

I've went over those arguemtns several times and I've formed myself a clear opinon. At worst those are good thought provocing talks. Well worth listening to.

/Fredrik

 

[rogerl]

Whatever the fundamental theory is, it should explain Bell's Theorem or *instantaneous* correlations say 10 billion light years distance. What is the most promising approach. Timelessness or geometrylessness in the fundamental theory?

 

[czes]

Forget Time - Carlo Rovelli (2008)
http://www.fqxi.org/data/essay-contest-files/Rovelli_Time.pdf

 

[Fra]

Forget Time - Carlo Rovelli (2008)
http://www.fqxi.org/data/essay-contest-files/Rovelli_Time.pdf

This is a good contrast to Smolin's talk.

I'd encourage anyone to read/listen to BOTH, then make up your mind which is most sound :)

They represent two different perspectives.

/Fredrik

 

[rexrino]

I find some problems with Smolin's work, especially the ideas surrounding black-holes vacuuming up our universe and expelling it out into another universe (worm-holes). If that were true, we should see some kind of event in our cosmos, that represents matter being poured into our space (at least some type of energy radiation). Some could argue that that is exactly what happens with a big bang.

Looking at string theory, if two panes were to bang together, you would have a big bang. But what if the panes bang together as the pull between a black hole in one universe becomes so great it draws them together, they touch and "Bang". The question that comes to my mind is:
what is it in Universe(1) that is attracted to the black hole in Universe(2).

Some could argue that Universe(2) doesn't exist until the contents of the black-hole expulsion takes place. That is, U2 doesn't really exist until U1 fills it with the matter that black-holes convert normal matter into. Kinda like a compression algorithm that can be uncompressed on the other side of U1. My question is: what is the container that is U2?

I wonder if there is such a thing as normal space and infinite-space. That is, infinite space is a place of nothingness that normal space expands into.

Of course you would have to prove that infinity exists. This simple math does that:

0 + 0 = 0
If you have nothing, you cannot derive anything from that situtation ergo, nothing would ever exist.
Now, 1 + 0 = 1 with one meaning something.
This seems to imply that something (1) has always existed, or that all universes are contained within the fabric of eternity, which is without bounds. But, if you had eternity, you wouldn't really need string theory because there would be no need of panes of existence because eternity is unlimited in size and could contain all the matter to manage local matter systems, like a galaxy for instance.

Perhaps the cosmos is not expanding so much as randomly moving about in eternity(space?), due to constant collisions of galaxies, neutron stars, etc.

It's just an idea.

 

[Noja888]

I find some problems with Smolin's work, especially the ideas surrounding black-holes vacuuming up our universe and expelling it out into another universe (worm-holes). If that were true, we should see some kind of event in our cosmos, that represents matter being poured into our space (at least some type of energy radiation). Some could argue that that is exactly what happens with a big bang.

Time is required to demonstrate changes in space. Space is required to demonstrate changes in time. (I believe QM has exceptions in certain schools of thought)

Past the event horizon of a black-hole the 'space/time' of GR comes to a singularity. Does this signify that time does not 'flow' in this region of space beyond the event horizon? (Think Reference Frames - Bob watches Alice move slower and slower but never falls into the black hole) Would this be what the geometry of GR at a singularity is trying to tell us? That no time flows here perhaps?

Another pondering of mine (thought experiment/visualization) is that my 'normal' 3D reality sits upon the surface of a 4D sphere. With time inflating the 4D sphere - thus expanding the universe. Gravity through matter slows this inflation (flow of time) down through some sort of "frictional resistance". In the absence of matter the inflation (flow of time) can proceed uninhibited (dark energy?)

I am by no means challenging the status quo of QM and GR - but trying to create new ideas and concepts that may further us down the rabbit hole. 8)

 

[member 11137]

Whatever the fundamental theory is, it should explain Bell's Theorem or *instantaneous* correlations say 10 billion light years distance. What is the most promising approach. Timelessness or geometrylessness in the fundamental theory?

Why should we put time and geometry in opposition (either or)? Why can we not accept to think that the local variations of the geometry (the flow of the evolution) are giving us the pertinent tool to define a local chronology?

 

[rexrino]

Why should we put time and geometry in opposition (either or)? Why can we not accept to think that the local variations of the geometry (the flow of the evolution) are giving us the pertinent tool to define a local chronology?

Flowing where? What is the force that directs this flow?

 

[rexrino]

Time is required to demonstrate changes in space. Space is required to demonstrate changes in time. (I believe QM has exceptions in certain schools of thought)

Past the event horizon of a black-hole the 'space/time' of GR comes to a singularity. Does this signify that time does not 'flow' in this region of space beyond the event horizon? (Think Reference Frames - Bob watches Alice move slower and slower but never falls into the black hole) Would this be what the geometry of GR at a singularity is trying to tell us? That no time flows here perhaps?

Another pondering of mine (thought experiment/visualization) is that my 'normal' 3D reality sits upon the surface of a 4D sphere. With time inflating the 4D sphere - thus expanding the universe. Gravity through matter slows this inflation (flow of time) down through some sort of "frictional resistance". In the absence of matter the inflation (flow of time) can proceed uninhibited (dark energy?)

I am by no means challenging the status quo of QM and GR - but trying to create new ideas and concepts that may further us down the rabbit hole. 8)

Time is required to measure the change in space, like millimeters are required to measure the change in length. We measure velocity as a vector, having both change in direction and change in length. It hard for me to consider the expansion of the universe in that way, change in length with change in time. It's like trying to say that velocity is really change in direction + change in length + change in time or a 3 part vector.

I'm the same as you, trying to voice my questions in a way so someone smarter than me can get me the answer I'm looking for or tell my I'm moving in the wrong direction.

 

[member 11137]

Flowing where? What is the force that directs this flow?

The force? The dark energy which is causing the expansion of the universe.

Where? Ask God (with all my respect).

Best regards

 

[rexrino]

The force? The dark energy which is causing the expansion of the universe.

Where? Ask God (with all my respect).

Best regards

I havent' had much luck with questions about the cosmos directed to god. I hope you've done better.

Dark energy is a pretty dark subject at this time, especially if you try to link it in with the forces of nature.

I'm still looking for proof, which hasn't been explicitly demonstrated. I'm still open to the idea myself but don't know how to go about contrasting it to normal matter.

 

[negru]

Now, 1 + 0 = 1 with one meaning something.
This seems to imply that something (1) has always existed, or that all universes are contained within the fabric of eternity, which is without bounds. But, if you had eternity, you wouldn't really need string theory because there would be no need of panes of existence because eternity is unlimited in size and could contain all the matter to manage local matter systems, like a galaxy for instance.

Perhaps the cosmos is not expanding so much as randomly moving about in eternity(space?), due to constant collisions of galaxies, neutron stars, etc.

It's just an idea.

I'm impressed with the sheer amount of wisdom you are able to extract from such a simple formula. Have you considered the equation

2 + 0 = 2?

I'm anxious to know what you make of this one.

 

[czes]

What do you think about it:
The particle in General Relativity is localised in the spacetime.
The particle in Quantum Mechanics is not localised at all, the spacetime doesn't exist and there is a quantum information relation only.

 

[rexrino]

I'm impressed with the sheer amount of wisdom you are able to extract from such a simple formula. Have you considered the equation

2 + 0 = 2?

I'm anxious to know what you make of this one.

2 is simply two somethings combined together.

I goes without saying to the average child prodigy that:

if 1= n then n^n is simply the sum of all 1's necessary to accumulate to the value of n^n.


Mind you it is understood that hydrogen with only one proton is the bases for all the other chemicals in the known universe. By combining the simple hydrogen atom together into a mass where gravity can work its magic, you get all the other chemicals. We are assuming that there is an affinity between hydrogen atoms. Do you know that that affinity is?

I'm not saying that hydrogen has always existed <smile>;

but something has always existed. What it is is another question entirely.

1 something is a better starting place than nothing. This is what I'm saying.

What is the set of all nothing?

 

[member 11137]

I havent' had much luck with questions about the cosmos directed to god. I hope you've done better.

Dark energy is a pretty dark subject at this time, especially if you try to link it in with the forces of nature.

I'm still looking for proof, which hasn't been explicitly demonstrated. I'm still open to the idea myself but don't know how to go about contrasting it to normal matter.

With my (ironic) answer to your question:"Where?" I meant that nobody knows where the whole universe is going... So we are condamned to make hypothesis far behind the real capacities of our brain...

Is the existence of dark energy contested? No I don't think so. Just its nature stays unknown. Is the expansion of our universe contested? No I don't think so. What is expanding? is perhaps the question. As a matter of fact: the volume certainly is the basic answer.

Concerning the dissertation about ... + ... = ... just take care in which set you are calculating. For example in non commutative one you could also get 0 = 1 + 1 which, symbolically speaking, would mean that something can arise from nothing... if zero means "nothing".

Otherwise and to come back to your initial question: see the discussion "Connes Rovelli paper on... "

 

[zetafunction]

but can't we forget time or treat it as another geommetrical space coordinate ??

so we live in a 4-dimensional space with no time only SPACE

 

[member 11137]

but can't we forget time or treat it as another geommetrical space coordinate ??

so we live in a 4-dimensional space with no time only SPACE

First of all I am not a professional in physics = many people here can give quite better answers than me.

I think one must make a distinction between 1) what equations in mathematics seem to induce = all dimensions (inclusively the time dimension) are on the same level (a kind of equivalence) and 2) what physics, really allows.

Concerning the last point, I am not certain that the sensation to become older (the time) is equivalent to: I walk 1 mile in that direction. Why? Because I always need time to walk but I shall also be older even if I do not walk (I am at rest in my local frame).

 

[tom.stoer]

First of all one must distinguish between time, time and time. There at at least three times we can talk about:

1) coordinate time which is so to a lare extend arbitrary and physically meaningless; it is so to speak the 4th (timelike) dimension which could be absorbed in a re-definition of space; nevertheless it has some different properties than spatial dimensions, e.g. one cannot go backward in time

2) proper time which is measured by an observer (on his comoving wristwatch); it can be used as coordinate time for this specific observer; it is physical as it can be measured, but it is somehow "private" and two different observers will in general not agree

3) a kind of process time which sets an (external, macroscopic) time scale; a single photon or a single electron do not feel any time; they do not "get older"; a pion will not "feel" any time, but it can decay, so if you do not have a single pion but a collection of pions each pion itself does not feel aging, but it could "observe" other pions, count them, and see that their number decreases due to the decays; this is something like a prototype for process time (unfortunately pions cannot see, count, ...); a lonely astronaut could use his watch (or a collection of pions) as timescale; but even w/o an own watch his body sets certain time scales, e.g. his heartbeat, breath, hunger, aging and dying.

I hope you see the difference.

If one uses a formulation of canonical gravity "time" will disappear completey. But this does only mean that coordinate time (1) is unphysical. In order to specify a time in the sense of (2) you have to introduce a local system according which one can define proper time; that means there must be something that says "here", that "devides the universe" in the "local system" and "the rest". In order to specify a process time the system must be large enough to allow for decay and aging processes, and ist must be small enough to allow for a local interpretation (the aging and expansion of the universe is no reasonable process time for us :-) So the time we feel is due to the definition of selected regions of space with physical processes defining a process time. This time in the sense of (3) has nothing to do with the fundamental definition of spacetime but is an emergent phenomenon.

We do not yet have a theory unifying all known interactions / forces with gravity. As long as this theory does not exist we can simply write down Einstein's equations and ask where the different notations of time do come from. Formally this look like

G = T

where G is the Einstein tensor encoding information regarding geometry (gravity), and where T is the stress energy tensor encoding information regarding all other interactions.

(1) is entirely intrinstic to G, (2) emerges when one defines an object that moves on a the geometry defined by G, and (3) emerges from T.

 

[czes]

Thank you Tom for this clarification.
Does it mean that the "process time" in quantum mechanics has encoded a constant value of time (information) for each change, relation (interference) between quantum information (fundamental particles) ?

 

[tom.stoer]

To be honest, I haven't seen any QM calculation that "generates" a process time. I know that there are very simple models in quantum gravity where a non-gravitational degree of freedom (e.g. a scalar field) serves as "time"; this geos into the right direction, but it is by no means sufficient. You could e.g. google for "Ashtekar" and "Loop quantum cosmology". The above mentioned Rovelli paper should prvide some references and information as well.

In QM there is only the "t" in the Schrödinger equation which is (you can see this in relativistic quantum mechanics) a coordinate time in the sense of (1)

 

[czes]

Rovelli's paper "Forget time" is very interesting.
I have found in another paper an interesting equivalent between Quantum Mechanics and General Relativity :
Tp / T(x) * Tp / T(y) = a Fg / Fe
where:
Tp * Tp - Planck's time squared = hG/c^5
T(x) , T(y) -Compton time of the oscillation of the particle x,y T=1/frequence = h/mc^2
due to Compton wave length of two interacting particles x,y (l= h/mc )
a – alfa=ke2 /hc = fine structure constant
Fg – Gravitational Newton's interaction Fg = Gm(x) m(y) /r2
Fe - Electrostatic Coulomb interaction Fe = ke2 /r2

If we derive from above that each relation of the non-local Compton wave causes a Planck's time dilation , their sum creates around a massive object with N=M/m particles a known gravitational time dilation
t(0)^2= (1-2GM/Rc^2)
Therefore I thought time is emergent just from the relation between non-local quantum information if each relation encodes 1 Planck time.

Excuse me I can't write in "tex".

 

[mquirce]

Czec. I was astonished by your post which is different from main stream. I write a post that was deleted . I am a lay man that do not merit to debate with scientist or physicist, but i think have the right to axpres my opinion (even invalid) when i see that somebody else has the same opinion.
Time eternal. Space without limit. Must be a particle of mater like Plank Mass but even it has the same unity are two different things : Mpl. = G*Mpl.^2 / (Rpl.*C^2) here in yhe left is plank mass in the right plank mater. The same fot el. common particles mx = G*Mpl.^2 / (rxcompton*C^2) . As i read your post there is somthing like this.
Don't be irritate please.

 

[rexrino]

With my (ironic) answer to your question:"Where?" I meant that nobody knows where the whole universe is going... So we are condemned to make hypothesis far behind the real capacities of our brain...

This is possibly true.

Is the existence of dark energy contested? No I don't think so. Just its nature stays unknown. Is the expansion of our universe contested? No I don't think so. What is expanding? is perhaps the question. As a matter of fact: the volume certainly is the basic answer.

Thought: if black holes are taking matter and energy out of our local space, wouldn't there be a contraction effect noted instead of an expansion -water level decreasing in container as the water goes down the drain?

Answer:
(1) Not enough black holes to register an effect?

(2) Matter is being rerouted back into the same universe (feedback loop for wormhole travelers. Could be that wormholes are one way streets).

(3) Black holes are local effect that don't effect the level of expansion. (See 2).

Concerning the dissertation about ... + ... = ... just take care in which set you are calculating. For example in non commutative one you could also get 0 = 1 + 1 which, symbolically speaking, would mean that something can arise from nothing... if zero means "nothing".

The equation has to be correct for the communicative property to apply over any set N.

I don't see where I stated that 0 + 1 = something different than 1 . I guess if you incorporate negative numbers, -1 + 1 = 0 would apply (a matter and anti-matter universe, collision).

If such a condition did exist, you have no information to reach a conclusion about weather they ever existed. The mass, energy, particles, wave structures (strings), all would be annihilated (Leaving a gravity-hole?)

Otherwise and to come back to your initial question: see the discussion "Connes Rovelli paper on... "

Maintaining ones grasp on reality is paramount if we are to derive substance in the study of the cosmos. It is so large and we have yet to determine its boundaries. For this reason, we need to keep hypothesis as simple as possible or it could expand out of minds reach.



I'll check it out if it has sufficient summaries. I have a tremendous "reading" workload.

 

[rexrino]

First of all I am not a professional in physics = many people here can give quite better answers than me.

I think one must make a distinction between 1) what equations in mathematics seem to induce = all dimensions (inclusively the time dimension) are on the same level (a kind of equivalence) and 2) what physics, really allows.

Concerning the last point, I am not certain that the sensation to become older (the time) is equivalent to: I walk 1 mile in that direction. Why? Because I always need time to walk but I shall also be older even if I do not walk (I am at rest in my local frame).

Yes, but if you were immortal, how much older would you really be? You are concerned about time because you feel you are somehow physically effected by it. Physically, your displacement is all that has happened. If you choose to measure that displace in units of time as well as distance, then it appears that time has somehow effected you but were you really effected by time in any fashion?

I'm not a professional physicist either. I'm just an old man that has thought about this stuff, without allowing the math to enterfer with my imagination for many years. Like Einstien said, He imagined he was riding on the head of a light beam...

I've checked out the links you gave me and it is so much gibberish... I actually read every pdf file on the site. "I'm a fast reader." And, I find that Michio Kaku is tied up in this nonsense... No wonder the young can't figure anything out. They need to steep out of the shadow of these self-interested mathematicians and let their imaginations soar.

 

[rexrino]

To be honest, I haven't seen any QM calculation that "generates" a process time. I know that there are very simple models in quantum gravity where a non-gravitational degree of freedom (e.g. a scalar field) serves as "time"; this geos into the right direction, but it is by no means sufficient. You could e.g. google for "Ashtekar" and "Loop quantum cosmology". The above mentioned Rovelli paper should prvide some references and information as well.

In QM there is only the "t" in the Schrödinger equation which is (you can see this in relativistic quantum mechanics) a coordinate time in the sense of (1)

Your a smart thinker.

Look at a sine wave... it is a representation of a periodic material change in state, or change in displacement. I If two water waves collide with one another, the forces of that collision combine to displace the water particles. They can be in a positive direction, giving you a tall wave or a negative one, where the difference in the forces of collision neutralize one another yielding no displacement or a small one. It' the same with an electrical wave. All we are really looking at... the real parts that are effected are the particles themselves or the force of the magnetic fields surrounding the electrons in the case of electricity waves.

Time is not a force that has impact on matter or electromagnetism. To say that gravity distorts space is to say that it distorts the matter contained in that space. Time will look as if it were effected also, because the ruler (time measuring stick) we use to measure the distortion is also distorted by the gravity. But, to the person taking the measurement it will look as if nothing has been distorted at all and their measuring stick is still just fine thank you very much. <smile>

Think of collision. Think of Transfer of force (summation of forces).

All this hoopla about time is really a result of the fact an electron suddenly jumps from one state of energy to another... the "quantum" jump, in an incremental way instead of a linear transition from one potential to the other. But... does it really? I don't believe in miracles. Something else is going on here and, because we can't figure it out, we develop a whole lot of math to fill in the void.

In electronics, we have a saying, there is no such thing as a true square wave...because a There is no such thing as "zero rise time". a point cannot have a potential of zero value and some other value (+) or (-) at the same time. So, in reality a wave form on an oscilloscope is actually "sloping" from one state of potential to the other. It doesn't make a quantum leap from place to place.

 

[member 11137]

Lee Smolin stated in Trouble with Physics (page 256):

"More and more, I have the feeling that quantum theory and general relativity are both deeply wrong about the nature of time. It is not enough to combine them."

<snip>

"We have to find a way to unfreeze time - to represent time without turning it into space. I have no idea how to do this. I can't conceive of a mathematics that doesn't represent a world as if it were frozen in eternity. It's terribly hard to represent time, and that's why there's a good chance that this representation is the missing piece."

-----
What is he talking about? Anyone got an idea, or share new papers or perhaps have a clue to an eventual solution?

Perhaps he is indirectly thinking about the work of Gödel.

 

[rexrino]

Nope...
There's a lot of loose talk about the confusion of time and it's relationship with space.

 

[Agent Lumino]

Hallo friends,
Could it be that the expansion of the universe is 4-dimensional and the radial expansion progress is equal to the speed of light?
I know, there is no way to measure the “speed” of time in m/s. But measuring will be possible, if a relativistic speed limit also exists in higher dimensions. Then we could measure the speed of time in m/q, where “q” is a maybe 5-dimensional time experience.
I have the imagination that our time experience is equal to the experience of a photon and its traveling direction. Photons cannot see where they are going to, but they “know” where they have been yet. Also they feel no time – as we know it. Time is standing still for photons. If the expansion of the universe had a relativistic progress, we could have an answer to the question, why we cannot see higher dimensions. (This could also be a solution for the rolled up dimensions in the string theories.)

I will give another argument by calculating the Hubble constant in a very easy way.
The expansion speed of the universe is defined by the Hubble-constant and is about 71 km/s per Megaparsec.
The NASA proofed this constant and published a value of 72 km/s per Megaparsec.

I assume, that the universe is closed and looks like a 4-dimensional balloon. The universe, as we know, is the surface of the balloon. The balloon is expanding and I assume that the radial expansion speed is the speed of light.
Then I can start to calculate:
If the radial speed is 300.000km/s (speed of light) the perimeter of the balloon increases with 2r*pi
2 * 300.000km/s * 3.14 = 1.885.000 km/s
If the universe exists since 13 billion years, the perimeter is now: 13 billion years * 2 * pi = 81.68 billion light-years or 25.000 Megaparsec, because 1 Megaparsec are 3.26 million light-years.
The Hubble constant can now be found, if one divides 1.885.000 km/s by 25.000 Mpsc.
These are = 75.4 km/s per Megaparsec.
I think that this is a strong indication, that our universe is closed and the radial expansion speed is the speed of light.

Please let me know if there is a sense in assuming a solution like this.
Agent Lumino

 

[rexrino]

How can we conclude that the universe exists for 13 billion years and how would this effect the equation if it were twice that or less? Would not the Hubble constant cease to be a constant in your equation?