# B Quantization of energy and ultraviolet catastrophe

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1. Mar 25, 2017

### Cozma Alex

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?

2. Mar 25, 2017

### Staff: Mentor

You will get better answers if you can tell us which parts of the explanations you did understand and where you are getting lost.

3. Mar 25, 2017

### Cozma Alex

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 doesnt fit the experiments, but how can the quantization explain this? How did plank came to the conclusion that energy was carried in packets?

4. Mar 25, 2017

### Staff: Mentor

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/Einstein-Quantum-Quest-Valiant-Swabian/dp/1491531045

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/Introduction-Probability-Models-Tenth-Sheldon/dp/0123756863

Thanks
Bill

Last edited by a moderator: May 8, 2017
5. Apr 1, 2017

### mpresic

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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