Quantization of energy and ultraviolet catastrophe

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Discussion Overview

The discussion centers on the quantization of energy and its role in addressing the ultraviolet catastrophe, exploring both historical context and theoretical implications. Participants seek to understand how quantization resolves discrepancies between theoretical predictions and experimental results related to blackbody radiation.

Discussion Character

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

Main Points Raised

  • One participant questions how the quantization of energy can solve the ultraviolet catastrophe, indicating a lack of understanding of existing explanations.
  • Another participant suggests that providing specific areas of confusion could lead to better answers.
  • A participant expresses understanding of the failure of the Rayleigh-Jeans model but seeks clarification on why it fails and how quantization plays a role in this context.
  • It is noted that assuming continuous absorption and emission leads to infinite predictions as frequency increases, suggesting a flaw in the classical approach.
  • Discussion includes the historical perspective, mentioning Planck's initial failure to prove his hypothesis and his eventual assumption that energy is exchanged in packets.
  • One participant highlights Bose's discovery regarding the indistinguishability of photons and its implications for statistical mechanics, suggesting that traditional counting methods do not apply.
  • A recommendation is made for further reading in a specific book that discusses the correspondence between Planck and Einstein, indicating that introductory texts may not provide a complete explanation.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and confusion regarding the quantization of energy and its implications for the ultraviolet catastrophe. Multiple viewpoints are presented, and no consensus is reached on the explanations provided.

Contextual Notes

Participants reference historical models and the limitations of classical physics in explaining blackbody radiation, indicating unresolved mathematical and conceptual challenges in the discussion.

physics user1
How can the quatization of energy solve the ultraviolet catastrophe?
I tried explanation on internet and on the book but i found nothing, can you help me?
 
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You will get better answers if you can tell us which parts of the explanations you did understand and where you are getting lost.
 
Nugatory said:
You will get better answers if you can tell us which parts of the explanations you did understand and where you are getting lost.
I understood that to the old prediction based on raleight jeans model did not work, but why doesn't work? I saw the graph and of course it's because it doesn't fit the experiments, but how can the quantization explain this? How did plank came to the conclusion that energy was carried in packets?
 
Cozma Alex said:
I understood that to the old prediction based on raleight jeans model did not work, but why doesn't work? I saw the graph and of course it's because it doesn't fit the experiments, but how can the quantization explain this? How did plank came to the conclusion that energy was carried in packets?

It fails for a couple of reasons. If you assume absorption and emission is continuous the math says nothing stops it being infinite as frequency increases - so must be wrong. Plank tried to prove it, failed and resorted to a trick - not taking a limit properly that was basically the assumption energy was exchanged in packets.

You will find a full discussion of the history here:
https://www.amazon.com/dp/1491531045/?tag=pfamazon01-20

But the simplest reason of all was discovered by Bose. Photons are literally indistinguishable meaning if you exchange two of them it makes no difference. This means the normal counting methods used in Statistical Mechanics do not apply. Do it the right way and low and behold you get the right answer.

Interestingly once you get that it's not really an issue in physics - but of probability modelling. It' even explained in Ross's standard book on the subject:
https://www.amazon.com/dp/0123756863/?tag=pfamazon01-20

Thanks
Bill
 
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The most complete explanation I have seen is in a book, From q-numbers to c-numbers, by Darrigol, Be prepared to read several chapters for a complete interesting explanation including correspondence between Planck and Einstein. Otherwise, many introductory QM texts, for example, Powell and Crasemann graze over the explanation
 
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