Unruh-ly radiation inside nucleons

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Discussion Overview

The discussion revolves around the concept of Unruh radiation, particularly its implications within atomic and nuclear systems, as proposed by Shahar Hod. Participants explore the potential effects of Unruh radiation on quarks inside nucleons and its relation to gravitational fields and dark matter. The conversation includes theoretical considerations, challenges to Hod's assumptions, and speculative connections to broader cosmological phenomena.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants reference Hod's analysis of Unruh radiation in atomic and nuclear systems, noting that it may be negligible for atomic systems but significant for quarks inside nucleons.
  • One participant questions the energy density associated with Unruh radiation in gravitational fields, suggesting it could relate to dark matter effects or the cosmological constant.
  • Several participants express skepticism regarding Hod's assumptions, arguing that relativity does not apply at atomic scales and that electrons do not experience relativistic mass increase in atomic orbits.
  • Another participant proposes that while classical mechanics may struggle at extreme scales, special relativity (SR) is still valid at atomic scales, though quantum mechanics complicates its application.
  • One participant highlights the extreme conditions quarks may experience, suggesting that their acceleration could lead to significant Unruh radiation effects.

Areas of Agreement / Disagreement

Participants exhibit a mix of agreement and disagreement. While some support Hod's ideas, others challenge his assumptions and the applicability of relativity at atomic scales. The discussion remains unresolved with competing views on the implications of Unruh radiation.

Contextual Notes

The discussion includes various assumptions about the behavior of particles at atomic scales, the equivalence principle, and the nature of Unruh radiation. There are unresolved mathematical considerations and speculative connections to cosmological phenomena that are not fully explored.

marcus
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in case anyone is interested
Unruh radiation is somewhat like Hawking radiation, a quantum gravity thing----so I will post it here
http://www.arxiv.org/abs/hep-th/0510089
Unruh Radiation in Atomic and Nuclear Systems
Shahar Hod
2 pages
"We analyze the Unruh radiation effect experienced by an accelerated particle in atomic and nuclear systems. For atomic systems, the effect is shown to be negligible as compared to the characteristic energy of the system. On the other hand, we find that a quark inside a nucleon may experience Unruh radiation whose energy is comparable with the quark's own mass[/color]. We discuss the implications of these results."

Shahar Hod already provoked a disturbance with his conjecture about BH seminormal vibration modes and the relation to Hawking radiation. Always looking for excitement.
 
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marcus said:
in case anyone is interested
Unruh radiation is somewhat like Hawking radiation, a quantum gravity thing----so I will post it here
http://www.arxiv.org/abs/hep-th/0510089
Unruh Radiation in Atomic and Nuclear Systems
Shahar Hod
2 pages
"We analyze the Unruh radiation effect experienced by an accelerated particle in atomic and nuclear systems. For atomic systems, the effect is shown to be negligible as compared to the characteristic energy of the system. On the other hand, we find that a quark inside a nucleon may experience Unruh radiation whose energy is comparable with the quark's own mass[/color]. We discuss the implications of these results."
Shahar Hod already provoked a disturbance with his conjecture about BH seminormal vibration modes and the relation to Hawking radiation. Always looking for excitement.
What is the energy per unit volume, the energy density, of a space with a given temperature? I wonder because due to the equivalence principle, there's no distinction between acceleration and gravitation. So if an accelerating reference frame has a certain Unruh radiation and associated temperature for anybody in that accelerated reference frame, then by the equivalence principle so does a body in a graviational field feel an Unruh temperature. So if there is a temperature in space alone simply because it is in an accelerated reference frame due to gravity, then there is an energy density of that space due to that temperature. Could it be that this energy density which might surround a galaxy be enough to produce the dark matter effects? For that matter, since there is a gravitational field associated with the entire universe, perhaps this Unruh effect due to the accelerated reference frames of gravity might actually be the cosmological constant. And perhaps this cosmological constant is not evenly distributed but is more dense around galaxies so that we see its effects as dark matter. Anybody want to do the math and get a Nobel prize?
 
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I think Hod missed the boat on that one, marcus. Relativity does not work at atomic scales... e.g., electrons do not experience relativistic mass increase while 'orbiting' an atomic nucleus.
 
Chronos said:
I think Hod missed the boat on that one, marcus. Relativity does not work at atomic scales... e.g., electrons do not experience relativistic mass increase while 'orbiting' an atomic nucleus.

I think I should wait to see whether or not he missed the boat, and if he did then for what reason.

I would agree that thinking of the electron as "orbiting" the nucleus is of limited usefulness (maybe a wave slopping around is better) but if you DO then I believe a typical speed for an electron in a bohr H atom is 1/137 of the speed of light. At that speed there wouldn't be much relativistic mass increase, would there?

I think I will keep my powder dry on this one, and see if there is any response to Hod.
 
This is the first time I have totally disagreed with you, marcus. I greatly appreciate your enthusiasm and sincerity. It's inspirational, but, I think you missed the boat on this one. Hod's assumptions are just plain wrong, IMHO.
 
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Mike2 said:
What is the energy per unit volume, the energy density, of a space with a given temperature? I wonder because due to the equivalence principle, there's no distinction between acceleration and gravitation. So if an accelerating reference frame has a certain Unruh radiation and associated temperature for anybody in that accelerated reference frame, then by the equivalence principle so does a body in a graviational field feel an Unruh temperature. So if there is a temperature in space alone simply because it is in an accelerated reference frame due to gravity, then there is an energy density of that space due to that temperature. Could it be that this energy density which might surround a galaxy be enough to produce the dark matter effects? For that matter, since there is a gravitational field associated with the entire universe, perhaps this Unruh effect due to the accelerated reference frames of gravity might actually be the cosmological constant. And perhaps this cosmological constant is not evenly distributed but is more dense around galaxies so that we see its effects as dark matter. Anybody want to do the math and get a Nobel prize?

The effects of local environmental change (for instance here) :http://www.physlink.com/News/050920SpinProtonsNeutrons.cfm

makes as a good scale example?

The internal working of material may be constant for all matter and observers contained?..example the:http://csep10.phys.utk.edu/astr162/lect/gclusters/attractor.html

the effects we observe being external to the portion of space known as the Great Attractor, may not be existing for any observers "contained" inside the actual area/volume of space?
 
Chronos said:
I think Hod missed the boat on that one, marcus. Relativity does not work at atomic scales... e.g., electrons do not experience relativistic mass increase while 'orbiting' an atomic nucleus.

You would probably like to rephrase this to: SR works perfectly at atomic scales
but QM makes it harder to apply classical relativistic mechanics.

-----------------------------------------------

Going to the extreme:

A classical particle spinning with a frequency corresponding to Plancks mass (E=hf)
at a Compton radius corresponding to Planck's length has an acceleration of:

5.56078 1051 meter/s2

and thus observes Unruh radiation with a temperature of:

[tex]T_U \ = \ \frac{\hbar a}{2 \pi c k_B} \ = \[/tex] 2.25489 1031 degrees.

Which is exactly Planck's Temperature divided by [itex]2\pi[/itex] :smile:

(odd factor [itex]2\pi[/itex] Mr. Unruh? ...)

But then to put things into perspective:

Our classical particle with Planck's mass would feel a centrifugal force at
a (Compton) radius of Planck's length of:

1.2102755 1044 kg m / s2

Which is enough to accelerate the Earth (5.9742 1024 kilograms)
to it's orbiting velocity around the Sun of circa 30,000 m/s in a time of:

1.5 10-15 seconds or 1.5 femtoseconds...

Well it's not so strange that classical mechanics gives up somewhere. :smile:
Regards, Hans
 
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Hans de Vries said:
You would probably like to rephrase this to: SR works perfectly at atomic scales
but QM makes it harder to apply classical relativistic mechanics.

...

thanks for such a nice rephrasing of Chronos' point, Hans! If that is what he is saying I can agree fully---would have no reservations at all.

BTW I recognize that force as the Planck force c4/G
and the acceleration you mentioned is the unit acceleration in the Planck system of units
 
I don't think anyone disposed of this issue raised by Hod.

Shouldnt we keep track of it a bit longer? Apparently the quarks inside the nucleon are being jerked around a lot and experiencing a lot of gees like 10^50 gees, which must make them see lots of Unruh radiation----a kind of hallucination which people can get from abruptly accelerating

shall we say that this is not our problem---just something that the quark feels. Hod says the energy density in this Unruh radiation is comparable to the mass of the quark. Is there some reason that this does not matter? Did Hod make a mistake?
 

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