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Copernicus
2012-Oct-29, 04:58 AM
Lets propose a graviton had a virtual energy of 10^-52 joules. If there was a production of virtual gravitons, what would the uncertainty principle allow for its lifetime.

Shaula
2012-Oct-29, 07:51 AM
Are you talking about the dE.dt > h-bar/2 relationship? If you assumed that to hold then you get t = 1.05e−34 / 0.5e-52 = 4.2e18s

But bear in mind what speed they travel at.

Copernicus
2012-Oct-29, 02:20 PM
Are you talking about the dE.dt > h-bar/2 relationship? If you assumed that to hold then you get t = 1.05e−34 / 0.5e-52 = 4.2e18s

But bear in mind what speed they travel at.

I was thinking at least the speed of light.

Shaula
2012-Oct-29, 03:06 PM
Yes, they travel at the speed of light. And gravity is an infinite range force. So like photons gravitons will have an effectively infinite lifetime.

Copernicus
2012-Oct-29, 10:00 PM
Yes, they travel at the speed of light. And gravity is an infinite range force. So like photons gravitons will have an effectively infinite lifetime.

If expansion of universe would dilute these gravitons, but mass and time increase the density of gravitons, how would this affect the rate of time?

Shaula
2012-Oct-29, 10:25 PM
These are virtual gravitons - you cannot thin of them in a classical way. The underlying entity is the field, that is what you need to think about in cosmological terms.

Time does not increase the density of virtual gravitons

Copernicus
2012-Oct-29, 10:29 PM
These are virtual gravitons - you cannot thin of them in a classical way. The underlying entity is the field, that is what you need to think about in cosmological terms.

Time does not increase the density of virtual gravitons

Does this mean that virtual gravitons never die, they keep getting produced, but the density exchange of virtual gravitons never increases?

Shaula
2012-Oct-29, 10:44 PM
They are how something interacts with the field, they are not the field. Also they no not never die - they are absorbed and created as required.

I am not sure where you are going with this but without some background in Quantum Field Theory it is not going to go anywhere.

Copernicus
2012-Oct-30, 01:53 AM
They are how something interacts with the field, they are not the field. Also they no not never die - they are absorbed and created as required.

I am not sure where you are going with this but without some background in Quantum Field Theory it is not going to go anywhere.

I was just wondering if there is a theory for calculating the rate of time? It seems that if there are gravitons, not virtual gravitons, and they last forever, and if the universe is expanding, it could be the start of a theory for rate of time changing. I don't really know if there is a quantum field theory for gravity that is main stream.

Shaula
2012-Oct-30, 07:45 AM
It would be more strictly true to say that there is not a theory with gravitons that is core mainstream. So it is pretty hard to answer your question. Sorry but without some key elements there is not much more than can be said:
1) How do gravitons interact with time?
2) Which interactions result in gravitons being released? (this requires some detail knowledge of mixing and coupling matrices)
3) When you say rate of time do you mean an absolute rate? (GR is not going to be happy)

Copernicus
2012-Oct-30, 11:08 PM
It would be more strictly true to say that there is not a theory with gravitons that is core mainstream. So it is pretty hard to answer your question. Sorry but without some key elements there is not much more than can be said:
1) How do gravitons interact with time?
2) Which interactions result in gravitons being released? (this requires some detail knowledge of mixing and coupling matrices)
3) When you say rate of time do you mean an absolute rate? (GR is not going to be happy)

Thanks for the questions Shaula.

1) I would imagine that gravitons would be what causes general relativity and they would interact with time the way that general relativity does.
2) I would think of gravitons being given off by some type of momentum transfer.
3) I think of time as being a passing of certain type of repetitive action. Nothing really real. The day being one revolution of the earth, but not really meaning anything by itself.

Shaula
2012-Oct-31, 06:41 AM
You cannot have your answers to 1 and 3 at the same time. The density of gravitons is a local thing. GR time effects are mostly relating what 2 observers in motion see. Things like the underlying symmetry that leads to the twin paradox break down. You are essentially making GR a local thing, modifying proper time. It cannot be that and work.

Sorry, you clearly have some scheme in your head here but your answers are, to me, inconsistent and far, far too woolly to get to the level of detail required for the answers you are after.

Copernicus
2012-Oct-31, 08:13 PM
You cannot have your answers to 1 and 3 at the same time. The density of gravitons is a local thing. GR time effects are mostly relating what 2 observers in motion see. Things like the underlying symmetry that leads to the twin paradox break down. You are essentially making GR a local thing, modifying proper time. It cannot be that and work.

Sorry, you clearly have some scheme in your head here but your answers are, to me, inconsistent and far, far too woolly to get to the level of detail required for the answers you are after.

You're right, that doesn't make sense, gravitons would cause gravity.

Reality Check
2012-Nov-01, 02:14 AM
Thanks for the questions Shaula.

1) I would imagine that gravitons would be what causes general relativity and they would interact with time the way that general relativity does.
2) I would think of gravitons being given off by some type of momentum transfer.
3) I think of time as being a passing of certain type of repetitive action. Nothing really real. The day being one revolution of the earth, but not really meaning anything by itself.
Hi Copernicus: you seem to be thinking of time as a particle or field. It is not - time is a dimension.
Gravitons do not cause GR because GR is not a theory of particles. It is quantum field theory that says that gravitons should exist because gravitational fields exist. I suspect that would be true even for Newtonian gravity!

Gravitons can be thought as "given off" by masses as mediators of the gravitational force between them.

Time is measured as the passing of certain type of repetitive action, e.g. a day is a certain amount of time.

Copernicus
2012-Nov-01, 02:37 AM
Hi Copernicus: you seem to be thinking of time as a particle or field. It is not - time is a dimension.
Gravitons do not cause GR because GR is not a theory of particles. It is quantum field theory that says that gravitons should exist because gravitational fields exist. I suspect that would be true even for Newtonian gravity!

Gravitons can be thought as "given off" by masses as mediators of the gravitational force between them.

Time is measured as the passing of certain type of repetitive action, e.g. a day is a certain amount of time.

I was thinking that time slowed down in a high gravitational field. Am I wrong in this?

Shaula
2012-Nov-01, 06:42 AM
I was thinking that time slowed down in a high gravitational field. Am I wrong in this?
Time is measured to pass more slowly for things in a gravitational field relative to an external observer. A small but very important distinction.

Jeff Root
2012-Nov-01, 08:50 AM
That statement could be misleading.

Time is measured to pass more slowly for things deeper in a
gravitational field than for things less deep in a gravitational
field.

The location of an observer isn't germaine. I know that isn't
what you meant.

For example, if you wanted to calculate the passage of time
on Mercury relative to the passage of time at Jupiter's cloud
tops, you would need to take into account Mercury's gravity,
Jupiter's gravity, and the Sun's gravity. You could ignore the
gravity of the Earth and of the Galaxy.

-- Jeff, in Minneapolis

Copernicus
2012-Nov-01, 12:49 PM
Good point to Shaula and Jeff Root. How do observers relate to distant past?

Jeff Root
2012-Nov-01, 01:31 PM
You can probably clarify that question some.

A poster here recently appeared to be arguing that all
of the observed cosmic redshift could be accounted for
by gravitational redshift. That was nonsense, but my
understanding, based on my vague memory of reading
something, somewhere, many years ago, is that about
1% of the cosmic redshift is due to the difference in
gravitational potential between the time when the light
was emitted and the Universe was overall more dense,
and now, when it is less dense.

-- Jeff, in Minneapolis

Copernicus
2012-Nov-01, 01:37 PM
You can probably clarify that question some.

A poster here recently appeared to be arguing that all
of the observed cosmic redshift could be accounted for
by gravitational redshift. That was nonsense, but my
understanding, based on my vague memory of reading
something, somewhere, many years ago, is that about
1% of the cosmic redshift is due to the difference in
gravitational potential between the time when the light
was emitted and the Universe was overall more dense,
and now, when it is less dense.

-- Jeff, in Minneapolis


Thanks Jeff, didn't realize it would be so little.

I think the current big bang theory is that space is expanding, but not everything in it. At some point all the galaxies and matter had to expand as well since the matter and galaxy could not have fit into a singularity. what kind of expansion is that and how would it affect time?

Strange
2012-Nov-01, 01:55 PM
I think the current big bang theory is that space is expanding, but not everything in it. At some point all the galaxies and matter had to expand as well since the matter and galaxy could not have fit into a singularity.

Early on the expansion was uniform because the distribution of matter was pretty much uniform. As clouds of gas collapsed (gravity) to form stars and galaxies, the expansion was no longer even. Only the largely empty space between galaxies (or clusters) continued to expand. Galaxies are now gravitationally bound and do not expand.


what kind of expansion is that and how would it affect time?

I don't know how that question can be answered. The "rate" at which time passes is relative and can only be determined by comparing two clocks. How do you compare a clock now with one 13 billion years ago?

We choose a set of coordinates where time was always the same. You can, as I understand it (not much), choose coordinates where time changes since the big bang; putting the time of the big bang in the infinite past. (Like the expanding space vs shrinking matter discussion in another thread - just another coordinate choice.) But then you have to make all sorts of other changes to fundamental constants over time (the speed of light is not constant, etc). This does not tell you anything new, it is just a more confusing way of doing the same thing. So we choose the simpler model where space expands, the big bang was 13.7bn years ago and fundamental constants don't change over time.
[I hope I have that basically right. No doubt someone more expert will point out any errors!]

Copernicus
2012-Nov-01, 05:37 PM
Early on the expansion was uniform because the distribution of matter was pretty much uniform. As clouds of gas collapsed (gravity) to form stars and galaxies, the expansion was no longer even. Only the largely empty space between galaxies (or clusters) continued to expand. Galaxies are now gravitationally bound and do not expand.



I don't know how that question can be answered. The "rate" at which time passes is relative and can only be determined by comparing two clocks. How do you compare a clock now with one 13 billion years ago?

We choose a set of coordinates where time was always the same. You can, as I understand it (not much), choose coordinates where time changes since the big bang; putting the time of the big bang in the infinite past. (Like the expanding space vs shrinking matter discussion in another thread - just another coordinate choice.) But then you have to make all sorts of other changes to fundamental constants over time (the speed of light is not constant, etc). This does not tell you anything new, it is just a more confusing way of doing the same thing. So we choose the simpler model where space expands, the big bang was 13.7bn years ago and fundamental constants don't change over time.
[I hope I have that basically right. No doubt someone more expert will point out any errors!]

Now that is interesting!

trinitree88
2012-Nov-01, 07:05 PM
Copernicus. Recently, (last summer), CERN announced @ the LHC the resonance @ ~ 125.9 Gev/c 2...the purported Higg's particle, or something like it. If it is the Higg's then it is also the graviton as the carrier of mass, creating mass chunk by chunk, changes the local gravitational field, and does so piecewise, making it a quantum carrier of the gravitational force in the manner of the other vectors of the other forces....the photon (carrier of the electromagnetic force), the gluon (carrier of the color force in quantum chromodynamics), the W+, W-. and Z0(carriers of the weak force.
A particle has more mass, it has more gravity...inseparable.
This would be nice since it would confirm a prediction made in April 1982, using Howard Georgi's SU(5) symmetry, that the Z could function as a graviton as a neutrino/antineutrino pair...(one of the decay channels for the 125.9 resonance) or even as a pair of neutrino /antineutrino pairs. When you split the mass/energy of a Z, you get ~ 45 Gev, and if that attaches to an ambient W, you get exactly 125.9 Gev/c 2....a composite particle made up of a W and a graviton interacting.
Put my money where my mouth was and wrote a paper on it for the Grav. Research Foundation @ Babson College over 20 years ago, and successfully predicted the coincidences @ 3.2 sigma between the Mont Blanc., Kamiokande, IMB, and Baksan Neutrino detectors and the Rome and Maryland bar gravitational wave detectors during supernova 1987a, five years before it happened. ( peer-reviewed and published by others ~ 25 times)
Where will this show up again? The tau-theta puzzle...the apparent fall of parity by Lee and Yang, in the kaon decays can be resolved with conservation laws intact if some of the kaons are interacting with low mass Z0 particles as neutrino/antineutrino pairs...low energy gravitons. Then when the graviton is emitted with the pions, the missing parity is restored. Note bien that the experimental rest masses of the tau and the theta are not equal. pete


SEEhttp://www.nobelprize.org/nobel_prizes/physics/laureates/1980/fitch-lecture.pdf


SEE:http://en.wikipedia.org/wiki/Tsung-Dao_Lee and Thank you Professor Lee for the best physics talk I ever heard @ MIT's Physics Colloquiem. Funny. Poignant. Interesting. Simply the best. Kudos pete

SEE:http://en.wikipedia.org/wiki/Kaon notice there is a known difference in mass between the k-zero short and the k -zero long, and the short does not decay to three pions....no graviton there.

Strange
2012-Nov-01, 07:27 PM
If it is the Higg's then it is also the graviton

Don't they have different spin?

Shaula
2012-Nov-01, 07:31 PM
If it is the Higg's then it is also the graviton as the carrier of mass
No no no no no no no!! The graviton and the Higgs are totally different. They couple to different things, they have different spins, they have different masses, they have different symmetries associated with them. They are not and cannot be the same thing at all if you accept the Standard model of them and the Higgs mechanism which gives rise to the Higgs boson in the first place. I know there are threads in research trying to make the links you have in your post but they are even more speculative than graviton extension to the Standard model. You cannot state them as fact as you have.

Copernicus
2012-Nov-01, 08:13 PM
Copernicus. Recently, (last summer), CERN announced @ the LHC the resonance @ ~ 125.9 Gev/c 2...the purported Higg's particle, or something like it. If it is the Higg's then it is also the graviton as the carrier of mass, creating mass chunk by chunk, changes the local gravitational field, and does so piecewise, making it a quantum carrier of the gravitational force in the manner of the other vectors of the other forces....the photon (carrier of the electromagnetic force), the gluon (carrier of the color force in quantum chromodynamics), the W+, W-. and Z0(carriers of the weak force.
A particle has more mass, it has more gravity...inseparable.
This would be nice since it would confirm a prediction made in April 1982, using Howard Georgi's SU(5) symmetry, that the Z could function as a graviton as a neutrino/antineutrino pair...(one of the decay channels for the 125.9 resonance) or even as a pair of neutrino /antineutrino pairs. When you split the mass/energy of a Z, you get ~ 45 Gev, and if that attaches to an ambient W, you get exactly 125.9 Gev/c 2....a composite particle made up of a W and a graviton interacting.
Put my money where my mouth was and wrote a paper on it for the Grav. Research Foundation @ Babson College over 20 years ago, and successfully predicted the coincidences @ 3.2 sigma between the Mont Blanc., Kamiokande, IMB, and Baksan Neutrino detectors and the Rome and Maryland bar gravitational wave detectors during supernova 1987a, five years before it happened. ( peer-reviewed and published by others ~ 25 times)
Where will this show up again? The tau-theta puzzle...the apparent fall of parity by Lee and Yang, in the kaon decays can be resolved with conservation laws intact if some of the kaons are interacting with low mass Z0 particles as neutrino/antineutrino pairs...low energy gravitons. Then when the graviton is emitted with the pions, the missing parity is restored. Note bien that the experimental rest masses of the tau and the theta are not equal. pete


SEEhttp://www.nobelprize.org/nobel_prizes/physics/laureates/1980/fitch-lecture.pdf


SEE:http://en.wikipedia.org/wiki/Tsung-Dao_Lee and Thank you Professor Lee for the best physics talk I ever heard @ MIT's Physics Colloquiem. Funny. Poignant. Interesting. Simply the best. Kudos pete

SEE:http://en.wikipedia.org/wiki/Kaon notice there is a known difference in mass between the k-zero short and the k -zero long, and the short does not decay to three pions....no graviton there.

I sure like the term resonance for particles and/or Higgs, z, w, kaon etc.

Copernicus
2012-Nov-01, 08:20 PM
Copernicus. Recently, (last summer), CERN announced @ the LHC the resonance @ ~ 125.9 Gev/c 2...the purported Higg's particle, or something like it. If it is the Higg's then it is also the graviton as the carrier of mass, creating mass chunk by chunk, changes the local gravitational field, and does so piecewise, making it a quantum carrier of the gravitational force in the manner of the other vectors of the other forces....the photon (carrier of the electromagnetic force), the gluon (carrier of the color force in quantum chromodynamics), the W+, W-. and Z0(carriers of the weak force.
A particle has more mass, it has more gravity...inseparable.
This would be nice since it would confirm a prediction made in April 1982, using Howard Georgi's SU(5) symmetry, that the Z could function as a graviton as a neutrino/antineutrino pair...(one of the decay channels for the 125.9 resonance) or even as a pair of neutrino /antineutrino pairs. When you split the mass/energy of a Z, you get ~ 45 Gev, and if that attaches to an ambient W, you get exactly 125.9 Gev/c 2....a composite particle made up of a W and a graviton interacting.
Put my money where my mouth was and wrote a paper on it for the Grav. Research Foundation @ Babson College over 20 years ago, and successfully predicted the coincidences @ 3.2 sigma between the Mont Blanc., Kamiokande, IMB, and Baksan Neutrino detectors and the Rome and Maryland bar gravitational wave detectors during supernova 1987a, five years before it happened. ( peer-reviewed and published by others ~ 25 times)
Where will this show up again? The tau-theta puzzle...the apparent fall of parity by Lee and Yang, in the kaon decays can be resolved with conservation laws intact if some of the kaons are interacting with low mass Z0 particles as neutrino/antineutrino pairs...low energy gravitons. Then when the graviton is emitted with the pions, the missing parity is restored. Note bien that the experimental rest masses of the tau and the theta are not equal. pete


SEEhttp://www.nobelprize.org/nobel_prizes/physics/laureates/1980/fitch-lecture.pdf


SEE:http://en.wikipedia.org/wiki/Tsung-Dao_Lee and Thank you Professor Lee for the best physics talk I ever heard @ MIT's Physics Colloquiem. Funny. Poignant. Interesting. Simply the best. Kudos pete

SEE:http://en.wikipedia.org/wiki/Kaon notice there is a known difference in mass between the k-zero short and the k -zero long, and the short does not decay to three pions....no graviton there.

I'm sure there are a lot of people deserving, but hope you get a Nobel for this, or at least a few million in grants for further work. The Tau-Theta parity problem would be great to solve, but I can't help but think that these are all resonances of something more fundamental!

Copernicus
2012-Nov-01, 08:22 PM
No no no no no no no!! The graviton and the Higgs are totally different. They couple to different things, they have different spins, they have different masses, they have different symmetries associated with them. They are not and cannot be the same thing at all if you accept the Standard model of them and the Higgs mechanism which gives rise to the Higgs boson in the first place. I know there are threads in research trying to make the links you have in your post but they are even more speculative than graviton extension to the Standard model. You cannot state them as fact as you have.

I really agree that the graviton would have to be spin 2. Who knows what the Higgs spin would be?

Shaula
2012-Nov-01, 08:37 PM
The LHC result was consistent with a spin-0, not spin-2. The Higgs is predicted to be spin-0

caveman1917
2012-Nov-01, 11:37 PM
I hope I have that basically right.

No you didn't, you got that fully right ;)

ETA: let me just add that the reason we choose to use our conventional coordinates is because they are natural for observers moving with the hubble flow. The coordinate time on the clock following that path will tick proper time. We could for example put the big bang in the infinite past using t' = \ln t = \ln \tau but then this coordinate time will not correspond to the time an actual clock ticks that moves with the hubble flow. So the big bang really was 13.7 billion years ago in the physical sense that an inertial clock that has existed all that time will now unequivocally read 13.7 billion years. Unless its batteries ran out in that time of course.

Strange
2012-Nov-01, 11:57 PM
No you didn't, you got that fully right ;)

Thank you!


Unless its batteries ran out in that time of course.

That would be a challenge even for the Clock of the Long Now (http://longnow.org/clock/)

trinitree88
2012-Nov-02, 03:50 PM
I sure like the term resonance for particles and/or Higgs, z, w, kaon etc.

Copernicus. Resonances are a flurry of activity around a certain energy level, at a particular beam flux (luminosity), indicating that there is an enhanced cross-section there for events to occur. Figuring out the algorithms to separate the possibilities keeps experimentalists employed ,and theorists musing,which is part of what it's all about.
SEE:http://en.wikipedia.org/wiki/Resonance_(particle_physics)

The width of the resonance is inversely proportional to it's half-life.

Note the Z and W masses SEE:http://en.wikipedia.org/wiki/W_and_Z_bosons

80.385 Gev/c sqr. 91.1876 Gev/c sqr.

half the Z is 45.838 Gev, add that to 80.385 yields 126.223 for your resonance, first noted by Lubos Motl in his blog as far as I know....right around the preliminary 125.9 at CERN. Envision a massive Z splitting in two to two of each half that mass, and this pair of half-mass z's picking on a pair of W's ....you get two resonances @ 126.2 Gev. Lubos makes several arguments for the spins of bosons in his theory, with some theories restricting possibilities for the graviton and others allowing differing spins. He does remain controversial in other areas but that's a separate issue. One has to credit his recognition of the resonant possibility.
I'd bet on the possibility of manipulating the two rates of the K-long , K-short decays with a neutrino beam of known luminosity. pete

Copernicus
2012-Nov-02, 05:41 PM
Copernicus. Resonances are a flurry of activity around a certain energy level, at a particular beam flux (luminosity), indicating that there is an enhanced cross-section there for events to occur. Figuring out the algorithms to separate the possibilities keeps experimentalists employed ,and theorists musing,which is part of what it's all about.
SEE:http://en.wikipedia.org/wiki/Resonance_(particle_physics)

The width of the resonance is inversely proportional to it's half-life.

Note the Z and W masses SEE:http://en.wikipedia.org/wiki/W_and_Z_bosons

80.385 Gev/c sqr. 91.1876 Gev/c sqr.

half the Z is 45.838 Gev, add that to 80.385 yields 126.223 for your resonance, first noted by Lubos Motl in his blog as far as I know....right around the preliminary 125.9 at CERN. Envision a massive Z splitting in two to two of each half that mass, and this pair of half-mass z's picking on a pair of W's ....you get two resonances @ 126.2 Gev. Lubos makes several arguments for the spins of bosons in his theory, with some theories restricting possibilities for the graviton and others allowing differing spins. He does remain controversial in other areas but that's a separate issue. One has to credit his recognition of the resonant possibility.
I'd bet on the possibility of manipulating the two rates of the K-long , K-short decays with a neutrino beam of known luminosity. pete

I am sure the answer is in there somewhere. Hard to figure out it is!