ELFT HÍRADÓ

[mcsete AT physx.u-szeged.hu]

Seminar

Speaker: Professor Dr. Sándor Varró
ELI-ALPS (Attosecond Light Pulse Source) Research Institute, Szeged, Hungary.

Date: 4 PM, 10 December (Wednesday) 2025.
Location: University of Szeged, Institute of Physics, Bay Zoltán class-room
& Teams link in PS.

Title: Continuity and discreteness of colours and quantum physics.

Abstract:
The elementary quantum of action h was discovered by Max Planck 125  
years ago, and the foundation of modern quantum mechanics was worked  
out by Werner Heisenberg in 1925. On the occasion of the round  
anniversaries of these path-breaking results, we summarize the main  
points and background of these discoveries. The investigations of  
Planck and Heisenberg aimed, respectively, to determine the continuous  
spectrum of black-body radiation (measured very accurately by F.  
Kurlbaum in 1898, O. Lummer u. E. Pringsheim in 1900), and the rules  
concerning the emission and absorption of discrete spectral lines. In  
each cases the earlier theoretical and experimental contributions of  
Gustav Kirchhoff are substantial. On one hand, Kirchhoff proved in  
1860 the universality of the ratio of heat- and light-emission and  
-absorption capabilities of bodies being in thermal equilibrium with  
the radiation. This universality allows one to model the material  
agent by „anything”, like an oscillating Hertzian dipole, as was done  
by Planck. On the other hand, in 1860 Kirchhoff and Bunsen invented  
the spectral analysis, which also delivered a vast amount of  
experimental data on optical transitions, which was the subject of  
Heisenberg’s work. After highlighting these achievements, we also plan  
to sketch the history of concepts on colours of light, in particular,  
the introduction of the notion of „spectrum” by Isaac Newton in 1704.  
We shall see that earlier the compound nature of white light was far  
not an option.

Everyone is welcome to attend.
Dr. Mária Csete

PS:
https://teams.microsoft.com/l/meetup-join/19%3ameeting_YzE5NzNhNzAtNDBiMC00MmE3LTlhMGItNjI5YWU4NGQxMjA0%40thread.v2/0?context=%7b%22Tid%22%3a%22b46e0a31-7f6f-4e13-bc63-dd805d38702c%22%2c%22Oid%22%3a%22abb6a558-2ccc-44d9-b9f5-d086d0bc7031%22%7d


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