Can photons act as medium for sound?

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Discussion Overview

The discussion revolves around whether photons, either collectively or individually, can act as a medium for the propagation of sound waves. Participants explore various contexts, including theoretical implications and practical applications, while addressing the nature of sound transmission and the interaction of light with matter.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants assert that photons do not collide with each other frequently enough to facilitate sound transmission.
  • One participant suggests that while photons do not typically collide, they can interact under certain conditions, though this may not lead to sound wave propagation.
  • Another viewpoint proposes that a powerful, modulated light beam could create temperature variations in a gas, potentially producing audible pulses, but questions the existence of systems that directly transmit sound through this method.
  • There are references to radio waves and their inability to transmit sound through temperature changes, with some participants challenging this assertion in the context of the original question.
  • Participants discuss the phenomenon of lightning, noting that it involves electrical heating rather than optical processes, and clarify that thunder is a shockwave rather than a sound transmitted by light.
  • One participant raises concerns about the theoretical feasibility of sound wave propagation in a photon gas, citing interactions and energy loss among photons.
  • A practical example is provided regarding laser surveillance, where a laser beam can carry sound information through vibrations caused by sound waves in a room.
  • Another participant recalls a project involving modulated light beams used to transmit voice, suggesting a historical context for the discussion.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the ability of photons to act as a medium for sound transmission. The discussion remains unresolved, with differing opinions on the nature of interactions between photons and sound waves.

Contextual Notes

Some claims depend on specific conditions and assumptions about photon interactions and the medium in which sound is transmitted. The discussion includes references to theoretical models and practical applications that may not be universally accepted or validated.

aditya_the quazarboy
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can light collectively or individual photons act as a medium for propagation of sound waves?
 
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No. For one thing, photons do not collide with each other.
 
aditya_the quazarboy said:
can light collectively or individual photons act as a medium for propagation of sound waves?
It's not clear what the context of this question is. It is certainly possible to use a powerful, modulated light beam to vary the temperature in a gas at a high rate, which could manifest itself as an audible pulse as the gas expands. But i don't know of a system that actually uses the effect to 'transmit' an audio signal and directly produce sound without some intermediate form of transducer.
 
Ever listened to a radio?
 
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dukwon said:
Ever listened to a radio?
I don't think that radio waves change the temperature t transmit sound
 
dukwon said:
Ever listened to a radio?

no! that is not correct ... not in the context of the OP's question
 
lychette said:
I don't think that radio waves change the temperature t transmit sound
If you focus a powerful case beam onto a small volume, it will raise the temperature fast and that can be audible. It is very hard to produce heating of air with focussed radio waves as the losses are too low to provide enough energy.
 
What about lightning.
 
  • #10
Buckleymanor said:
What about lightning.
That would be electrical heating - not optical.
 
  • #11
Buckleymanor said:
What about lightning.
The lightning isn't carrying any information that represents a sound.
The thunder is a shockwave resulting from rapidly heated air, and is a mix of random frequencies.
 
Last edited:
  • #12
mfb said:
Not frequent enough to transmit sound, but sometimes they do collide.

I am not sure this works, even in theory. Gas molecules trying to occupy the same space collide every time. Photons passing near each other interact a fraction of the time proportional to E6. That means the most energetic photons tend to interact more, and thus lose energy. In such a dissiptaive medium, the solutions to your wave equation are not sine and cosine, but rather sinh and cosh. I don't think you get sound waves. Or even waves.
 
  • #13
If this discussion continues I'll split it out. It is interesting, but not (B) level.
Vanadium 50 said:
That means the most energetic photons tend to interact more, and thus lose energy.
There has to be some equilibrium, especially if we ignore processes that change the number of photons.
I don't know how a region of higher density would propagate if we have a photon gas much larger than the mean interaction length.
 
  • #14
Don't know if this is what the OP was asking, but in laser serveilance, a laser is bounced off the window of a room, and into a receiver. Any sound waves in the room will cause the laser to vibrate. These vibrations can be measured by the receiver, and converted into sound over a speaker. Of course, the vibrations in the beam are not sounds per se, but the laser could be described as "a medium" that carries the sound from the room to the receiver.
 
  • #15
Not quite what the OP meant but... some decades ago there was a project in one of the electronics magazines that used a modulated beam of light (pair of torches) to send voice between two houses. Think it was intended as a kids toy.
 

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