Is there a limit to frequency?

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    Frequency Limit
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Discussion Overview

The discussion revolves around the question of whether there is a limit to the frequency and wavelength of photons, exploring concepts from quantum mechanics and theories of spacetime. Participants examine the implications of Planck scale physics, energy limitations, and the nature of spacetime in relation to these limits.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants propose that there is no limit to wavelength except for constraints imposed by the total energy of the universe and the conditions under which a photon could become a black hole.
  • Others argue that the limits on wavelength and frequency are dictated by the discrete nature of space and time, specifically referencing Planck length and Planck time as fundamental limits.
  • One participant suggests that energy limitations, such as those derived from the de Broglie relationship and mass-energy equivalence, imply that exceeding certain energy thresholds could lead to black hole formation.
  • Concerns are raised about the validity of claims regarding the Planck length, with some participants noting that not all theories of quantum gravity support the idea of discrete spacetime and that there is no experimental evidence for such claims.
  • Another viewpoint emphasizes that in mainstream physics, there is no upper bound on frequency, and thus no smallest wavelength, referring to the ultraviolet (UV) limit as frequency approaches infinity.
  • Participants discuss the implications of measuring Planck-sized objects and the potential for creating black holes, while also questioning the accuracy of information found in sources like Wikipedia.
  • Some participants express skepticism about the notion of discrete spacetime, asserting that mainstream theories, such as string theory, treat spacetime as a smooth manifold.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the existence of limits on frequency and wavelength, with no consensus reached on the validity of the Planck scale concepts or the nature of spacetime.

Contextual Notes

Limitations include the lack of experimental confirmation for Planck scale physics and the dependence on theoretical frameworks that may not be universally accepted among participants. The discussion reflects a range of interpretations and assumptions about quantum gravity and spacetime.

  • #31
This thread does have a precise answer. It's simply that you refuse to accept it. Electromagnetic wave frequency is a frame dependent quantity, so you can always find a frame where it's bigger.
 
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  • #32

Vanadium 50, I have a theoretical disagreement with this Wikipedia statement:
Wikipedia said:
Very high-frequency photons, which cycle at once per Planck time or faster, could potentially swallow themselves up in black holes from their own energy density, which would make it difficult or impossible to probe this time scale. In the quantum theory, this would mean that the Planck time should be the smallest unit of time physics can reason about in a meaningful way.

The principle of mass-energy_equivalence cannot be invoked here because the photon does not have any rest mass, and a Planck mass is not a particle in the Standard Model, therefore there is no QED channel available for a photon to generate a Planck mass, therefore a photons energy density, regardless of photon energy magnitude, cannot cause space-time to curve and absorb itself into its own Schwarzschild radius as a Planck mass particle.

I also disagree that Planck time is the smallest unit of time quantization, it is merely a product resulting from the criteria of defining the gravitational radius equivalent to Compton wavelength for mass particles. The General Relativity space-time manifold is still smooth at Planck scales.
r_G = \overline{\lambda}_C

What are the PF Science Advisors theoretical position regarding these statements?
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Reference:
http://en.wikipedia.org/wiki/Planck_time#Physical_significance"
 
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  • #33
I had also wondered about this, limits for f or wavelength.
But unfortunately do not have the background to understand it fully.

So my general physics is lacking... SchnIkes.

I will stick with the frames of reference answer in case I get asked.
 

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