Could a gravitational wave seperate a virtual particle pair?

[Sorcerer]

Is it possible for a gravitational wave to assist in the seperation of a virtual particle pair? Let's say our control model is of a VP produced in very flat space a long way from any strong gravitational field. In this case the 2 virtual particles quickly come in contact with their partner and annihilate.

 

Now, what if instead during that same series of events a gravitational wave crossed that part of space, could it be timed/positioned so that space expands, pulling the particles away from each other at the crucial moment and upon the following contraction the particles no longer align, preventing their annihilation. Could successive wavelengths as they pass increase this effect?

 

Would it be necessary for the wave to lose energy , ie transfer it to the new arrangement of the VP pair?

 

If this occurs, and drains the wave of energy, does it impose a maximum range on gravitational waves? Is that range where the amplitude drops to 0?

Edited February 11, 2016 by Sorcerer

[imatfaal]

I have no idea - but it is a neat thought.

 

I will await with interest what people say; whilst trying to get my head around wavelengths etc and whether it is even possible. BTW the idea of the gravitational wave imparting energy would of course "pay back" the energy "borrowed" to create the particle pair (like the shrinking of the black hole "pays it back"). In my naive notion the particle pair is so close and the time so short (it is related to the change in energy by plancks constant which is very very small) that no gross macrodistortion of space could interfere. But then some reports of the LIGO results say that the merging black holes emitted gravitational waves carrying away the mass energy equivalent of 3 solar masses in a fraction of a second - thas pretty extreme!

[Sorcerer]

I wonder if it's a question of wavelength, gravitational waves might need to have very small wavelengths to do this. Visualizing this a large wave length would be to smooth to change anything. However on second thought if the interaction was with the wave where one VP was above the x axis (or horizontal line of symmetry) and the other just below, the two may be carried in opposite directions. It could also be the case for the crest of the wave, the other axis of symmetry. Or am I seeing that wrong? Surely place 2 floating balls tied togther by a string in a wave tank, the least likely position they'd assume is touching and the string at maximum slack no matter what their size.

Edited February 11, 2016 by Sorcerer

[MigL]

The wave may not be analogous to an ocean wave.

( we've discussed this before on this forum )

So I'm not sure if the wave 'geometry' would lend itself to this effect, or what kind of gravitational gradient would be required.

 

But it is a very interesting proposition for someone with much better understanding of the situation and the mathematics involved than I have, to look at.

[Sorcerer]

The wave may not be analogous to an ocean wave.

( we've discussed this before on this forum )

So I'm not sure if the wave 'geometry' would lend itself to this effect, or what kind of gravitational gradient would be required.

 

But it is a very interesting proposition for someone with much better understanding of the situation and the mathematics involved than I have, to look at.

True, I guess, an ocean wave is bound by gravity, a buoyant object effected by surface tension and air resistance, so it's not a very good model. Of course a pair of balls would slip apart when caught either side of the crest, due to gravity. And of course one would be carried up the wave to the crest and the other fall into the trough, that's again surface tension and kinetic energy being greater than gravity at one point and less at another. So it's not the best analogy.

 

Maybe a better analogy/model would be a wave travelling through a liquid kept in micro gravity. The two balls representing the particles would be of neutral buoyancy and suspended in the liquid. Various ratios of the size of the balls to the size of the wavelength and amplitude could be tested to see how the relative flattening of the wave crest (just like the earths curvature appears flat to us), would effect the frequency of separation. There would be problems in this model though when the size of the balls became too small, Brownian motion would interfere with results. I'm guessing instead of an actual experiment this could be just modeled on a computer.

 

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Now assuming this is possible, it lead me to a thought, could gravitational waves, near their source, while still powerful, lend their energy to the creation of enough matter that it could account for some of the missing mass/dark matter? Wouldn't doing this extend the range of gravitys influence? If gravity can lend its energy to create mass, and that mass has a gravitational distortion on space itself, rather than gravity diminishing over distance from these events approximate to the inverse square law, some of its effect is replenished. (i'm having difficulty wording this, and also I am trying not to violate the conservation of energy).

 

OK, so as the gravitational wave begins, this is when the VP's are most likely to be separated, without knowing the formulas, just to roughly show this, lets say 1 unit of gravity is borrowed to separate the VP pair, The VP pair has gained energy and since it has it's own mass has it's own gravity, in order for there to not be a violation of conservation, 1/2 a unit of gravity is used to separate the pair and the each of the pair has 1/4 gravity each. This could be 0.1 to 0.45 and 0.45 or anything I don't know. Most of this created mass however is so close to the source of the waves that it doesn't take long for it to be reunited as the highest probability for a future path here is a common direction towards the massive object, but some does escape. So a prediction, a massive object becomes even more massive, in an anomalous way, shortly after the production of gravitational waves.

 

As the wave moves out a bit further away from the super massive objects, where the curvature of space is less significant, more of the VP's separated can drift freely and have more possible futures. The wave produces behind itself mass, it has effectively carried mass away from the event that created it and spread it more evenly. The effect being that, without the wave the mass would be concentrated at the event and gravity weaker at a long distance, but because of the wave gravity's range of effect is stretched out a bit further. This increase in range could also be mistaken for hidden mass. This range increase could help prevent the outer edges of galaxy's from separating and remove the need for dark matter.

 

Eventually, the wave lends more and more of its gravitational energy to the creation and separation of VP pairs, lending this energy influences the properties of the wave. As frequency reduces so does the frequency of possible events which separate VP pairs. As the amplitude decreases and the wavelength increase past a critical value the gravitational waves no longer appear steep enough (have enough energy) (the scale factor, the wave is flat) for the VP pairs to separate. Thus there is only a boosted gravitational influence over the short and medium range of the wave. At long range it just coasts on appearing to do as we predict currently.

It's thought LIGO detected a wave from 1.8 billion light years away, under my assumed model, it wouldn't be surprising if this effect no longer occurs at this distance. Modelling it might tell us what kind of range we could expect. But I really am getting ahead of myself, I need someone first to clarify if this is even a possibility.

I attempted some research to see if any similar ideas had been proposed, however trying to google anything with "gravitational waves" in it right now will give you a clusterf*ck of news stories, regardless of other key words. Anyway, this is as close as I got to a similar idea..... and it's really completely different.

 

http://phys.org/news/2011-11-quantum-vacuum-dark.html

[Mordred]

Ok first off I am not sure if it will cause VP separation. The closest analogy I can think of is Parker radiation. Which is an older VP pair production due to an expanding spacetime. (Was originally developed to attempt to explain DE.)

 

However gravity waves wouldn't generate enough energy/mass to account for DM or dark energy.

 

So let's just stick to seeing if separation is possible in the first place instead of following false lead garden paths.

 

In all honesty though VP production at a wave is probable, but VP particles are typically extremely short lived.

Edited February 12, 2016 by Mordred

[Sorcerer]

Ok first off I am not sure if it will cause VP separation. The closest analogy I can think of is Parker radiation. Which is an older VP pair production due to an expanding spacetime. (Was originally developed to attempt to explain DE.)

 

However gravity waves wouldn't generate enough energy/mass to account for DM or dark energy.

 

So let's just stick to seeing if separation is possible in the first place instead of following false lead garden paths.

 

In all honesty though VP production at a wave is probable, but VP particles are typically extremely short lived.

How long would it take for the anti particle of the pair to encounter a particle and annihilate if say the pair were separated in interstellar space? If this process was repeated regularly with the same probability on each successive wave front so as to maintain VPs in the vicinity, how long after the wave passes would normality return?

 

Why isn't the temporal redistribution of mass from the high density center of the galaxy to the edges, effectively extending the gravitational range of the most massive object able to account for DM? What fraction of DM might it contribute to?

 

Are there any long lasting sources of gravitational waves? Would say a binary black hole system in a stable orbit, say lasting billions of years, 1 be possible and 2 generate gravitational waves at regular intervals?

 

Is there a minimum requirement for production? Shouldn't all gravitational interactions cause waves, isn't it only the big events that are needed because detection is difficult, so we look for the biggest?

 

Surely even the earth causes a wave, as it rolls around the distortion of space caused by the sun it too locally distorts space as it moves forward it bends space in front and the space behind snaps back to its prior shape, shouldn't each moment be sending a tiny outward ripple from this constant orbital warping outwards?

[ajb]

You get particle production in space-times that are not static. So I imagine that particle production by gravitational waves is possible, though I know that Gibbons et al showed that there is no particle production from the interaction of gravitational waves and scalar fields. You would have to read the literature carefully here to properly answer the opening question.

[MigL]

I believe the original question was whether a gravitational wave could separate a virtual particle pair such that their 're-absorption' is impossible, thereby making them real.

Their energy would then be 'lost' by the gravitational wave such that it dissipates over time/distance.

[ajb]

I believe the original question was whether a gravitational wave could separate a virtual particle pair such that their 're-absorption' is impossible, thereby making them real.

That is one way of understanding particle production in non-static space-times, however I am not 100% sure that all the calculations reflect that interpretation.

 

EDIT: You can find the paper by Gibbons here.

He shows that a plane gravitational wave far from its source does not excite a scalar field: ie. no particle production.

Edited February 13, 2016 by ajb

[Sorcerer]

That is one way of understanding particle production in non-static space-times, however I am not 100% sure that all the calculations reflect that interpretation.

 

EDIT: You can find the paper by Gibbons here.

He shows that a plane gravitational wave far from its source does not excite a scalar field: ie. no particle production.

Being pressed for time, I won't read the paper right now. If you know however, what distance does he mean by "far"? I'm hoping he means galactic scales, because that's exactly what I was proposing, the wave initially separates a lot of particle pairs - in this region matter is dense and the vast majority annihilate/reunite with the gravitational source, this essentially cancels out any extra gravitational effects, making gravity behave as predicted. But in the mid range/interstellar range there is a prolonged excitation/increase in mass which essentially acts as an extension of the gravitational field. At longer distances however the wave has lost some of its energy and doesn't produce any/or very little additional mass.

 

It is the medium range increase, that could account for dark matter. Especially if we sum over all the gravitational waves in a galaxy, not just those we can observe from super massive encounters.

[ajb]

If you know however, what distance does he mean by "far"?

The work is mathematical in its very nature and so by far he means that the gravitational wave can be considered as a ripple in Minkowski space-time.

[Sorcerer]

The work is mathematical in its very nature and so by far he means that the gravitational wave can be considered as a ripple in Minkowski space-time.

So..... is it far as in opposed to close? What's close then?

 

That made little sense to me. Let's say the distance between the event A the gravitational wave emerges from a collision of black holes and B the same gravitational wave passes through a planet. What distance between those two events is far?

[ajb]

So..... is it far as in opposed to close? What's close then?

Close would mean that you could not reasonable consider the background space-time to be Minkowski. To be absolutely Minkwoski this distance would be understood as infinite. As the paper is not a paper about astrophysics, I doubt Gibbons thinks too hard about actual distances here.

 

 

That made little sense to me. Let's say the distance between the event A the gravitational wave emerges from a collision of black holes and B the same gravitational wave passes through a planet. What distance between those two events is far?

I have no idea on the numbers here. You would have to think about the distance at which the background geometry without any gravitational radiation is not very curved and that the curvature due to the gravitational wave will swamp the background.

 

You can also study gravitational waves on non-trivial backgrounds, but quantum field theory becomes harder to work with.

 

I will also say that calculations of collisions and so on are done using numerical methods. Gibbons needed a simple situation to examine by hand. Moreover, he wanted a reasonable notion of particle states, which means he needs to consider asymptotically flat space-times.

Edited February 16, 2016 by ajb