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Author Topic: Is the gravitational field decoherent?  (Read 4874 times)

Offline jeffreyH

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Is the gravitational field decoherent?
« on: 19/08/2014 21:11:30 »
The gravitational field does not quite involve information loss but it does modify signals. The path of light is bent as well as the trajectories of masses under its influence. Does decoherence describe this?


 

Offline jeffreyH

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Re: Is the gravitational field decoherent?
« Reply #1 on: 20/08/2014 19:15:21 »
Although I cannot think of any way of determining this superposition should be a property of the gravitational field.
 

Offline evan_au

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Re: Is the gravitational field decoherent?
« Reply #2 on: 20/08/2014 22:40:23 »
I think you were asking about: decoherence/quantum entanglement of gravitons?

In another sense, objects which are strong radiators of gravitons, such as closely orbiting neutron stars or black holes will emit a coherent beam of gravitons, which radiate outwards at the speed of light. The field generated by this source is sometimes represented as a spiral centered on the source. (The field structure gets a lot more complex during the final collision!)
 

Offline jeffreyH

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Re: Is the gravitational field decoherent?
« Reply #3 on: 20/08/2014 23:25:28 »
I think you were asking about: decoherence/quantum entanglement of gravitons?

In another sense, objects which are strong radiators of gravitons, such as closely orbiting neutron stars or black holes will emit a coherent beam of gravitons, which radiate outwards at the speed of light. The field generated by this source is sometimes represented as a spiral centered on the source. (The field structure gets a lot more complex during the final collision!)

I would imagine that the coherence is due to the density and the effect this has on the structure of the mass. At the moment I am interested in much less intense sources of gravitation. I haven't even thought about the effects of density on the gravitational field. I do wonder about the intense magnetic fields around dense objects. Would this be due to the velocity of the force carriers for magnetism? If at a lower velocity than c they may have more freedom of movement. I know that sounds unlikely within the current theories but I doubt the accretion disk is the source of the whole field.
 

Offline lightarrow

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Re: Is the gravitational field decoherent?
« Reply #4 on: 21/08/2014 12:23:23 »
The gravitational field does not quite involve information loss but it does modify signals. The path of light is bent as well as the trajectories of masses under its influence. Does decoherence describe this?
Are you asking this because of Roger Penrose's theory?
 

Offline jeffreyH

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Re: Is the gravitational field decoherent?
« Reply #5 on: 21/08/2014 20:36:08 »
The gravitational field does not quite involve information loss but it does modify signals. The path of light is bent as well as the trajectories of masses under its influence. Does decoherence describe this?
Are you asking this because of Roger Penrose's theory?

No. I sent a question through to the the team he is working with for guidance and have briefly looked at twistor theory. I did some of my work before I saw their inclusion of the maxwell equations. Their work is much more advanced and is prior to mine. I need to rework much of my own mathematics as I find it entirely unsatisfactory.
 

Offline evan_au

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Re: Is the gravitational field decoherent?
« Reply #6 on: 21/08/2014 22:29:11 »
Quote
I would imagine that the coherence is due to the density
I would prefer to say that the density of the orbiting objects allows a much stronger acceleration of larger masses, and much more intense gravitational radiation. With planets orbiting the Sun, the gravitational radiation is so slight that it can't be measured with current techniques.

The coherence is due to there being a single orbital frequency (which gets well under 1 second before the final colision of neutron stars), which causes coherent ripples in the fabric of spacetime. These ripples radiate outwards from the source, and have a frequency which is determined by the orbital frequency.

Gravitational wave researchers are looking for a distinctive signature: In the period leading up to a merger, there will be an increase in frequency and amplitude of the gravitational waves, followed by a sudden cessation.

Quote
I do wonder about the intense magnetic fields around dense objects. Would this be due to the velocity of the force carriers for magnetism?
The source of magnetism can be any material which conducts electricity, or has an electric charge or a magnetic moment. This can include conductive metal inside the Earth, conductive plasma in the Sun, potentially metallic hydrogen in Jupiter's core, neutron stars and superconductors.

The speed of carriers, their quantity, and how well they are aligned in the same direction all affect teh strength of a magnetic field. But more important in teh longer term is whether there is a mechanism to inject energy into teh magnetic field faster than the inevitable losses which cause it to decay over time.
 
Dense objects don't necessarily produce a magnetic field - as I understand it, a black hole can have an electric field (but doesn't have to), but it can't have a magnetic field extending outside the event horizon(?) However, dynamo effects in an accretion disk around a dense object can produce strong magnetic fields.
 

Offline jeffreyH

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Re: Is the gravitational field decoherent?
« Reply #7 on: 21/08/2014 22:49:59 »
Quote
I would imagine that the coherence is due to the density
I would prefer to say that the density of the orbiting objects allows a much stronger acceleration of larger masses, and much more intense gravitational radiation. With planets orbiting the Sun, the gravitational radiation is so slight that it can't be measured with current techniques.

That sounds reasonable.

The coherence is due to there being a single orbital frequency (which gets well under 1 second before the final colision of neutron stars), which causes coherent ripples in the fabric of spacetime. These ripples radiate outwards from the source, and have a frequency which is determined by the orbital frequency.

I would have to think about this one for a while. Tidal locking may well cause coherence when angular momentum is high but I am not quite convinced.

Gravitational wave researchers are looking for a distinctive signature: In the period leading up to a merger, there will be an increase in frequency and amplitude of the gravitational waves, followed by a sudden cessation.

This brings to mind the G2 gas cloud. I stopped following the progress a while back as the information seemed to dry up. That should have generated high energy particles if consumed. At the time I didn't think that would happen.

Quote
I do wonder about the intense magnetic fields around dense objects. Would this be due to the velocity of the force carriers for magnetism?
The source of magnetism can be any material which conducts electricity, or has an electric charge or a magnetic moment. This can include conductive metal inside the Earth, conductive plasma in the Sun, potentially metallic hydrogen in Jupiter's core, neutron stars and superconductors.

Agreed.

The speed of carriers, their quantity, and how well they are aligned in the same direction all affect teh strength of a magnetic field. But more important in teh longer term is whether there is a mechanism to inject energy into teh magnetic field faster than the inevitable losses which cause it to decay over time.

Dense objects don't necessarily produce a magnetic field - as I understand it, a black hole can have an electric field (but doesn't have to), but it can't have a magnetic field extending outside the event horizon(?) However, dynamo effects in an accretion disk around a dense object can produce strong magnetic fields.

I am not entirely convinced that a magnetic field would be trapped. However it would be a short-lived escape if it is possible. We would be talking about periods of time so short that we probably can't measure them.
 

Offline jeffreyH

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Re: Is the gravitational field decoherent?
« Reply #8 on: 22/08/2014 00:16:05 »
A quite recent but short article on the G2 gas cloud can be read here:

http://news.discovery.com/space/galaxies/our-galaxys-black-hole-does-not-have-the-munchies-140721.htm

Another can be read here:

http://www.huffingtonpost.com/2014/07/22/gas-cloud-black-hole-video_n_5609134.html

I can't find actual research results online yet.
 

Offline jeffreyH

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Re: Is the gravitational field decoherent?
« Reply #9 on: 22/08/2014 22:53:09 »
I found an interesting arxiv preprint.

http://arxiv.org/abs/quant-ph/9811059
 

Offline PmbPhy

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Re: Is the gravitational field decoherent?
« Reply #10 on: 23/08/2014 03:50:17 »
The gravitational field does not quite involve information loss but it does modify signals. The path of light is bent as well as the trajectories of masses under its influence. Does decoherence describe this?
This question doesn't make any sense to me. Recall the definition of decoherence at
http://en.wiktionary.org/wiki/decoherence
Quote
Decoherence is the process by which a quantum system interacts with its environment in such a way that no interference between states of the system can be observed.
How could that possibly apply to the gravitational field since a gravitational field can never be a quantum state.
 

Offline jeffreyH

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Re: Is the gravitational field decoherent?
« Reply #11 on: 23/08/2014 09:25:33 »
The gravitational field does not quite involve information loss but it does modify signals. The path of light is bent as well as the trajectories of masses under its influence. Does decoherence describe this?
This question doesn't make any sense to me. Recall the definition of decoherence at
http://en.wiktionary.org/wiki/decoherence
Quote
Decoherence is the process by which a quantum system interacts with its environment in such a way that no interference between states of the system can be observed.
How could that possibly apply to the gravitational field since a gravitational field can never be a quantum state.

I didn't say I thought I was right. There are a whole host of reasons to object to this idea. I have had some interesting feedback which I will now ponder.
 

Offline jeffreyH

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Re: Is the gravitational field decoherent?
« Reply #12 on: 23/08/2014 09:28:59 »
I think you were asking about: decoherence/quantum entanglement of gravitons?

In another sense, objects which are strong radiators of gravitons, such as closely orbiting neutron stars or black holes will emit a coherent beam of gravitons, which radiate outwards at the speed of light. The field generated by this source is sometimes represented as a spiral centered on the source. (The field structure gets a lot more complex during the final collision!)

The spiral representation intrigues me. It sounds a lot like Einstein's vortexes.
 

Offline evan_au

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Re: Is the gravitational field decoherent?
« Reply #13 on: 24/08/2014 05:48:24 »
Quote
The spiral representation intrigues me.
See: Animation of the spirals in Wikipedia. http://en.wikipedia.org/wiki/Gravitational_wave#Astrophysics_and_gravitational_waves

Quote
a gravitational field can never be a quantum state
I don't see why not.
An electromagnetic field can have a common quantum state, since photons are bosons (spin 1), and bosons can form a condensate under the right conditions, such as photons from a laser.
I don't see why gravitons can't be produced in a coherent form - if they exist, they are thought to also be bosons, with spin 2.

We can now produce laser beams in the laboratory and in the home; we can produce them with electricity and chemical reactions, we can block them with matter and reflect them with mirrors, and we can detect them with our eyes.
Producing measurable gravitational waves would require masses larger than we can comfortably fit in our Solar System, and we don't know how to block them, or shield/reflect them, and we have never detected them directly. Individually, gravitons have far less energy than a photon, so it's not surprising that we know far less about them.
« Last Edit: 24/08/2014 12:20:47 by evan_au »
 

Offline jeffreyH

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Re: Is the gravitational field decoherent?
« Reply #14 on: 24/08/2014 12:05:14 »
Quote
The spiral representation intrigues me.
See: Animation of the spirals in Wikipedia. http://en.wikipedia.org/wiki/Gravitational_wave#Astrophysics_and_gravitational_waves

Quote
a gravitational field can never be a quantum state
I don't see why not.
An electromagnetic field can have a common quantum state, since photons are bosons (spin 1), and bosons can form a condensate under the right conditions, such as photons from a laser.
I don't see why gravitons can't be produced in a coherent form - if they exist, they are thought to also be bosons, with spin 2.

We can now produce laer beams in the laboratory and in the home; we can produce them with electricity and chemical reactions, we can block them with matter and reflect them with mirrors, and we can detect them with our eyes.
Producing measurable gravitational waves would require masses larger than we can comfortably fit in our Solar System, and we don't know how to block them, or shield/reflect them, and we have never detected them directly. Individually, gravitons have far less energy than a photon, so it's not surprising that we know far less about them.

We assume that gravitons have far less energy because they appear to be weak. What if they do not themselves experience time dilation? I asked that question in another post but because they are hypothetical no one answered as at the moment it is unanswerable. Like the table cloth trick where pulling the cloth fast enough leaves the crockery in place the graviton may be too fast to impart all its attractive energy to the masses it interacts with. This is pure conjecture and cannot be pursued further here as it is new theories territory. It does need serious consideration.
 

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Re: Is the gravitational field decoherent?
« Reply #14 on: 24/08/2014 12:05:14 »

 

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