Seminar of Department of Theoretical Physics - Vladimír Balek (26.6.2024)

26.6.2024 at 14:00, Lecture room F1/125

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Vladimír Balek:
Historia magistra vitae: how Max Planck discovered quantum

Abstract: 
Ludwig Boltzmann distributed balls (molecules) into shelves (energy layers), as we are doing, too, when computing entropy of ideal gas, he just had indistiguishable boxes on the shelves (states) and distiguishable balls. Planck’s radiation law is obtained by a straightforward application of Boltzmann’s procedure to indistiguishable balls whose total number is not fixed (photons). Planck would probably not use this concept even if he would accidentally run into it when going through the options of how the interpolation formula for spectral density of blackbody radiation, just discovered by him, could possibly be explained. He was a respectable citizen, father of four, no “savage Messiah”. He had a better idea: switch balls and boxes. His balls were resonators, charged weights on springs interacting preferentially with radiation whose frequency coincided with their natural frequency, and the exchange of roles between balls and boxes meant that the resonators were not distributed between the states within the given interval of energy, but the intervals of energy were distributed between the resonators. In such a way the quanta of energy – fancy name for those intervals–balls – got into the description of resonators, and from there into the theory of electromagnetic field.

 

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