The Unruh effect

[GodOfBranson17]

Your gay.

[19cake69]

and your what 12 maybe? keep your comments to yourself little boy

[dannykanoista]

Interesting.

[trondreitan]

Thanks!

[WaiteDavid137]

Its an interesting speculation, but thats all it is for now. Unrah radiation doesn't actually exist, at least as far as I'm concerned until there is some experimental evidence for it.

[jas2754]

Thank You...Some of your description sounds similar to the description given of evaporation of Black Holes. At the event horizon vacuum flucuations creat a particle / antiparticle pair, and one particle is able to escape the Black Hole(it is just outside the horizon),the other not...what do you think?

[trondreitan]

That's a correct observation. The evaporation of black holes, known as Hawkings radiation has basically the same explanation as the Unruh effect. I've even heard that one can use the Unruh effect to describe Hawkings radiation, as any static system near a black hole can be locally approximated by a uniformly accelerated system.

[jas2754]

Thank You ... that makes sense that you can use the Unruh effect to describe HAwkings Radiation.

[starramus]

Hawking radiation, the Unruh effect, and Casimir light (sonoluminescence) are all produced by the same mechanism of converting virtual photons into real photons. Julian Schwinger put this idea forward and I agree with him. Sonoluminescence may well be the key to unlocking forces so powerful they would tend to be cosmological.

[BrunoTheQuestionable]

Presumably this must apply to us on the surface of the Earth, as our reference frame has a uniform acceleration of g. I suppose the event horizon must be at center of the Earth and this effect raises the temperature of the Earth very slightly.

[trondreitan]

I'm not so sure about that, as the earth's gravity field isn't uniform, there's no event horizon that I know of and because 1g of uniform acceleration would yield an event horizon one lightyear 'below' us. If the earth had been shrunk to a black hole you would however get an event horizon (of about a centimeter) and Hawking radiation. Hawking radiation is the spherical gravity field equivalence of Unruh radiation. I may very well be wrong, though.

[BrunoTheQuestionable]

Yes, that seems to make sense. You only get an event horizon if all the mass is concentrated at the center.

[trondreitan]

Your point has something going for it though. Our non-uniform gravity can at any local point be approximated by uniform acceleration. So maybe we do get Unruh/Hawkings radiation even without an event horizon. It's certainly possible that the quantum number-of-particle operator isn't the same for a free-falling observer as one standing on the ground.

[BrunoTheQuestionable]

Sorry for the delay - YT notifications are playing up.

We have to be very careful about any approximations when dealing with such extreme effects.

Surely there can't be any radiation without an event horizon, as it is the mechanism to separate the virtual particles.

[trondreitan]

Well, event horizons separating the virtual particles is the popular science explanation. As for the full quantum field way of describing it, I'm a bit more uncertain. Since a person on earth is locally equivalent to an uniformly accelerating system, it may be that the full treatment will give the same result, but I'm far from sure. Anyhow, it would be virtually impossible to observe one photon of wavelength one lightyear, though.

[trondreitan]

On further thought, I would not think that the popular science approach and the real quantum field approach would differ that much, so I would guess that an event horizon is neccessary for the real quantum field treatment, also.

[BrunoTheQuestionable]

The black hole analogy seems to be the closest - the distance from the observer to the event horizon being contracted by the spherical distortion of the space-time field ?

[trondreitan]

As I understand it, the analogy is often used the other way around. You get Hawking radiation because a spherical gravity field can be approximated by small local uniform acceleration fields. However, for the Hawking radiation, the characteristic wavelength of the radiation is the size of the black hole event horizon (radius), rather than a distance to it.

[mwilliams0]

very interesting thanks