ELFT HÍRADÓ

[Zimányiné Horváth Vera <Vera.Horvath AT eli-alps.hu>]

Előadó:                Varró Sándor (ELI ALPS)
Cím:                     The search for the fundamentals of ligh-matter 
interactions. A selection from the early contributions by Hungarian 
scientists.


Helyszín:             az ELI ALPS konferenciaterme (Szeged, Wolfgang Sandner 
utca 3.)
Időpont:             2025. május 30., 9 óra

Az előadás rövid összefoglalója:

In the centennial year of the birth of quantum mechanics (W. Heisenberg, 
1925), keeping an eye on the introduction of wave mechanics one year later 
(E. Schrödinger, 1926), we discuss some early Hungarian contribution to 
quantum physics. By slightly broadening the scope, and, besides, motivated by 
the bi-centennial year of the inauguration of the Hungarian Academy of 
Sciences, we overview some selected early works, concerning the nature of 
light and light-matter interactions.
We shall attempt to deal with the following results: The spectral formula by 
Radó von Kövesligethy (1885) for black-body radiation, which led to the 
correct displacement law, written down by W. Wien eight years later. The 
discovery and detailed measurement of the wide-angle interference of 
fluorescent light by Pál Selényi (1911), giving an experimental 
counter-argument against the needle radiation concept of photons, proposed by 
A. Einstein in his light-quantum hypothesis (1905). The description of the 
popagation of electromagnetic (hyrodynamic) discontinuities (shock waves) by 
Győző Zemplén (1913). The building up a correct mathematical description of 
quantum phenomena in terms of integral equations and bi-orthogonal function 
systems by Kornél Lánczos (1926). The derivation of the relativistic wave 
mechanical equation by János Kudar (1926) from variational principle in 
four-dimesional (Minkowski) space-time, in contrast to the five-dimensional 
Kaluza-Klein description. [The very extensive works by János von Neumann, 
Jenő Wigner, Ede Teller (and Leó Szilárd) will only be pointed out here, 
because these have long been substantial parts of texbooks on quantum 
mechanics.] Concerning quantum electrodynamics we highlight the 
gauge-invariant formulation given by Károly Novobátzky (1938), and developed 
further by János Valatin (1951). The ambiguity due to the different form of 
the energy-momentum tensors derived by M. Abraham (1902) and H. Minkowski 
(1908), and the concept of photon momentum in a dielectic medium have been 
clarified by Novobátzky (1947) and György Marx and Géza Györgyi (1954), and 
Károly Nagy (1955). By using the n-particle Dirac equation (including the 
Breit terms for retardation) the Kerr effekt and light scattering was 
analysed by Tibor Neugebauer (1931), who also gave a relativistic treatment 
of second harmonic generation in 1951. An important contribution to the 
probability interpretation of quantum mechanics is due to Imre Fényes (1952), 
who formulated a direct correspondence between the Schrödinger equation and 
the dynamics of Markov processes. The simultaneity, down to 10E-11 seconds, 
of the appearance of the outgoing photon and electron in Compton scattering 
was measured by Zoltán Bay (1955), by using the new photo-multipliers 
developed by him and colleagues. The photon correlation and single-photon 
experiments performed by András Ádám, Lajos Jánossy and Péter Varga (1955) 
and L. Jánossy and Zsolt Náray (1957), respectively, can be considered as a 
substantial contribution to the research on the nature of light. The first is 
sometimes considered as a forrunner of the photon bunching experiments by 
Hanbury-Brown and Twiss (1956). The coincidence factor of the photocounts was 
calculated by Géza Györgyi (1962), before the publication of the quantum 
optical coherence theory of R. J. Glauber (1963). The phase operator has been 
studied by Frigyes Károlyházy (1960), who gave a correct quantum optical 
description of the interference of photons.

A szemináriumon minden érdeklődőt szívesen látunk.
Az előadás online is meghallgatható a következő linken:
https://teams.microsoft.com/l/meetup-join/19%3ameeting_NDMyNTg3OGMtMjc4ZS00Y2ZlLTgyNjQtYjEzYWU4ZTA2YjZi%40thread.v2/0?context=%7b%22Tid%22%3a%22b207389a-c5cb-4cb0-a1ad-227b94e96448%22%2c%22Oid%22%3a%22c993efcb-59ae-4652-9f68-d7a313727128%22%7d


Üdvözlettel:
Horváth Vera


Vera HORVÁTH (Ms)
Head of Science Outreach Centre
Tel: +36 70 491 14 12
Email: vera.horvath AT eli-alps.hu<mailto:vera.horvath AT eli-alps.hu>

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