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Can Photons interact with Quantum Vacuum Fluctuations?

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sdf156
#1
Apr16-04, 11:13 PM
P: 2
Would it be possible for a photon traveling in space interact with a particle from a quantum vacuum fluctuation?
Say you have a particle antiparticle pair arise at just the right moment and the right frequency that one half of the pair absorbs a passing photon.
Would that cause an imbalance between the two particles enough to cause the photon to seem to dissapear and a sub-atomic particle to apprear in its place?
Can it be possible to then detect particles (probably very very few) scattering from a laser beam?
I would imagine that if this is possible, the particles that would arise from such interactions, would be really light-weight, such as neutrinos, or lighter.
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AntiMagicMan
#2
Apr17-04, 03:03 AM
P: 36
If they were neutrinos then we would have no reliable way of detecting them. If the photons were very high energy, then you would, and do expect to see particles produced.
EL
#3
Apr17-04, 06:19 AM
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Nice topic. In fact I'm thinking of doing my master thesis project about Photon-Photon scattering.

I would really appreciate some good links/references about Photon-Photon scattering in general, and the following subjects in particular:

*The Heisenberg-Euler Lagrangian, and the resulting nonlinear corrections to Maxwell's vacuum equations.

*Suggested Photon-Photon scattering detectors.

*High intensity lasers in general.

*Ultra-short intense lasers (chirped pulse amplification).

*Free electron laser (FEL).

sdf156
#4
Apr17-04, 09:35 PM
P: 2
Can Photons interact with Quantum Vacuum Fluctuations?

According to Olbers's Paradox, if there should be a star wherever you may look, then the sky should be awash with light and heat.
Now it was Edgar Allen Poe who then gave the answer that is accepted, saying that if the speed of light is finite, and the age of the Universe is finite, then the sky can be dark even in a spatially infinite Universe.

Ok, good answer, but think about it, isnt it true that if you had the most powerful telescope, and pointed it in any random direction, you would find clusters and clusters of galaxies?

So at least, why isnt the sky glowing a soft red? ( it does glow in microwaves though, but softly)


I think that if Photon-vaccum interactons occur, an interaction would be a very rare event, it would have to take place when a photon of light of the right polarization and energy, meets up with a particle anti-particle pair of the right energy and polarization, so that the photon is able to kick up the energy level of one of the particles.

Now photons of a given radiation, such as x-rays, or even gamma, would have a much better chance at interacting, because the energy borrowed from the vacuum would be more likely in the shorter wavelengths, but still, there is a probabbility, albeit small, that energy on the spectrum between ultraviolet to infrared, may be manifested.

At least, this may still result in an excess photon being emitted when the two particles pay back Mr. Heisenberg, who may dutifully return the change.
selfAdjoint
#5
Apr18-04, 09:33 AM
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Quote Quote by EL
Nice topic. In fact I'm thinking of doing my master thesis project about Photon-Photon scattering.

I would really appreciate some good links/references about Photon-Photon scattering in general, and the following subjects in particular:

*The Heisenberg-Euler Lagrangian, and the resulting nonlinear corrections to Maxwell's vacuum equations.

*Suggested Photon-Photon scattering detectors.

*High intensity lasers in general.

*Ultra-short intense lasers (chirped pulse amplification).

*Free electron laser (FEL).
A while back, as part of a discussion, I googled on photon-photon and also two photon. A number of research sites came up. There's a good deal out there. My impression was that photon-photon interactions only happen in situations of high energy, because they require some almost real pair production as an intermediate.
Nereid
#6
Apr18-04, 10:09 AM
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Quote Quote by sdf156
According to Olbers's Paradox, if there should be a star wherever you may look, then the sky should be awash with light and heat.
Now it was Edgar Allen Poe who then gave the answer that is accepted, saying that if the speed of light is finite, and the age of the Universe is finite, then the sky can be dark even in a spatially infinite Universe.

Ok, good answer, but think about it, isnt it true that if you had the most powerful telescope, and pointed it in any random direction, you would find clusters and clusters of galaxies?

So at least, why isnt the sky glowing a soft red? ( it does glow in microwaves though, but softly)


I think that if Photon-vaccum interactons occur, an interaction would be a very rare event, it would have to take place when a photon of light of the right polarization and energy, meets up with a particle anti-particle pair of the right energy and polarization, so that the photon is able to kick up the energy level of one of the particles.

Now photons of a given radiation, such as x-rays, or even gamma, would have a much better chance at interacting, because the energy borrowed from the vacuum would be more likely in the shorter wavelengths, but still, there is a probabbility, albeit small, that energy on the spectrum between ultraviolet to infrared, may be manifested.

At least, this may still result in an excess photon being emitted when the two particles pay back Mr. Heisenberg, who may dutifully return the change.
Welcome to Physics Forums sdf156!

Just to address your comment about Olber's Paradox: yes, in any direction that you look, you will 'see' the cosmic microwave background radiation. As you know, it's spectral energy distribution follows the 2.73K black body curve almost exactly.

However, when the Hubble Space Telescope looked at an almost random piece of sky it saw a great deal of black sky. It's likely that it detected proto-galaxies, among the first to be formed in the early universe. We also know what the faint outer extensions of the closer galaxies in the image will look like, when even deeper images are taken. Hence we could, now, simulate an image of the same piece of sky as if taken by a diffraction-limited 100m space telescope, integrating for 100 million seconds (and when we get around, finally, to taking such a picture, it won't look much different from our simulation). What would such an image - which would consume more disk space than that on all PF members' hard drives, combined - look like? Lots and lots of black sky. In other words, very few lines of sight to the edge of the universe actually intersect with the surface of a star; the night sky is, truly, dark.
marcus
#7
Apr18-04, 10:21 AM
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Quote Quote by selfAdjoint
... My impression was that photon-photon interactions only happen in situations of high energy, because they require some almost real pair production as an intermediate.
Floyd Stecker has some discussion of this and links in his survey
(in the "Rovelli's program" reference collection of links)

there is an energy threshhold level for gamma rays above which
the spectrum of gamma rays is expected to be influenced by
scattering
between the original gamma radiation and (of all things) CMB photons
IIRC it acts as a cutoff, because of photonphoton scattering between
gamma and CMB we dont expect to observe gamma above a certain energy
(Nereid may already have discussed this in some other thread)

this cutoff energy level has a name, which I forget, and there is
quite a bit of discussion about exactly where it ought to be and
whether it has already been observed or will soon be observed

anyway photonphoton scattering is beginning to play a real (if minor)
role in observational astronomy

somebody observed that this is a good thread topic and I agree!

Floyd Stecker's paper "Cosmic Physics: the High Energy Frontier"
is just one possible survey which IIRC mentions this, there may be better
marcus
#8
Apr18-04, 10:42 AM
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Quote Quote by Nereid
... Lots and lots of black sky. In other words, very few lines of sight to the edge of the universe actually intersect with the surface of a star; the night sky is, truly, dark.
the point I guess being that most lines of sight go clear back to a time when there wasnt any stars

lines of sight apparently dont go back any further than redshift z = 1100
which corresponds to when the universe was full of hot plasma
which scatters lines of sight---it's opaque like the surface of the sun


and that hot plasma of maybe 3000 kelvin now looks like 2.73 kelvin because of the z = 1100 redshift, so it is virtually black

an object at 2.73 kelvin glows hardly at all, it is very dark

the mathematics of why the sky is dark seems to boil down to
observing that

3000 divided by 1100 is around 2.73
Nereid
#9
Apr18-04, 01:25 PM
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Good point marcus, my reply was kinda sloppy.

In terms of Olber, the sky is "dark" in the sense that few lines of sight hit a star (or a cloud of gas & dust, which, following Olber, would be heated up to the temperature of the surface of a star). However, it is not 'black', because there are those microwaves.

I should also have said 'the edge of the *observable* universe', which is the CMBR today ... when we develop cool neutrino telescopes (pun intended ) we will be able to 'see' further.
marcus
#10
Apr18-04, 01:43 PM
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Quote Quote by Nereid
... when we develop cool neutrino telescopes (pun intended ) we will be able to 'see' further.
Yes!
today's neutrino telescopes can only see the comparatively warm or hot neutrinos----what a thought.

but to be able to see neutrinos around 2 or 3 kelvin!

At some point in each day I always am wondering why we are
not all astronomers. why doesnt everybody study astronomy?

i didnt notice any sloppiness, was only corroborating and elaborating
as usual
McQueen
#11
May11-04, 05:45 PM
P: 265
Would it be possible for a photon traveling in space interact with a particle from a quantum vacuum fluctuation?

The Polarisation of a vacuum is described as follows . A photon traveling through space , undergoes transformation into a ‘virtual’ electron-positron pair , which undergo annihilation giving rise to a photon . And so on. The reason that they are able to do so is because a vacuum is thought to contain infinite energy as a result of the Heisenberg Uncertainty Principle . How in view of this statement , can there be any doubt that a photon does interact with the vacuum ? The Vacuum might be taken as being all pervading , occupying the whole of space. It follows that photons are propagated through space through interactions with the vacuum. Being annihilated and giving rise in the process to new photons. This is similar to the manner inb which photons are propagated through a solid and is the whole point of QED.
kdouglas256
#12
May19-04, 11:42 AM
P: 7
Can someone explain in full how a photon will interact with a quatum vacuum. The previous entries do not explain how 'exactly' a photon will 'interact' to become a virtual (electron-positron) pair.

Can someone explain this please.

Does anyone have a reference book or internet which explains this in detail?

Many thanks.
TeV
#13
May19-04, 12:47 PM
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P: 182
If by interaction of HE single photon with clear vacuum (zero point energy of QM noise,without any thermodynamics of cosmic background radiation) is meant production of REAL electron positron pair -this is not going to happen.On other hand,two HE photons can interact and produce real pairs particle-antiparticle.Higher the energy higher the probability that to happen.
Photon-photon colliders
Creator
#14
May19-04, 06:51 PM
P: 547
Quote Quote by EL
Nice topic. In fact I'm thinking of doing my master thesis project about Photon-Photon scattering.

I would really appreciate some good links/references about Photon-Photon scattering in general, and the following subjects in particular:

*The Heisenberg-Euler Lagrangian, and the resulting nonlinear corrections to Maxwell's vacuum equations.

*Suggested Photon-Photon scattering detectors.

*High intensity lasers in general.

*Ultra-short intense lasers (chirped pulse amplification).

*Free electron laser (FEL).
This might interest you:
http://focus.aps.org/story/v8/st21

Then click on the enclosed physical review article

Creator
kdouglas256
#15
May20-04, 10:05 AM
P: 7
(TeV) Thanks for your entry and explanation about two photons being able to create a real pair (particle and anti-particle).

Can anyone also explain whether it is possible for a single photon in a quantum vacuum to react with a temporary virtual/real pair (either with the particle or anti-particle (electron or positron)). If so what happens?

Many thanks.
selfAdjoint
#16
May20-04, 02:01 PM
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A photon crossing the vacuum has no time to interact with anything, because its proper time is zero. Photons in the presence of matter (massive particles) can interact with the vacuum.
EL
#17
May20-04, 07:28 PM
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Quote Quote by Creator
This might interest you:
http://focus.aps.org/story/v8/st21

Then click on the enclosed physical review article

Creator
Thanks for your help. Actually my supervisor will be one of the authors!


Quote Quote by selfAdjoint
A photon crossing the vacuum has no time to interact with anything, because its proper time is zero. Photons in the presence of matter (massive particles) can interact with the vacuum.
Do you mean that photons can't interact with vacuum or...? Donīt think I get you?
Haelfix
#18
May20-04, 10:48 PM
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P: 1,677
We discussed this a few weeks ago. Photon-photon scattering is a real effect, and is important for certain highly energetic cosmic phenomena.

Its a second order effect in the e/m sector (primarly via the box diagram) and is measurable (in fact it has been measured).

If the interaction goes via graviton exchange, you get some cool predicted effects as well (though its completely swamped in practise).


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