Lajos Jánossy

Lajos Jánossy (2 March 1912 – 2 March 1978) was a Hungarian physicist, astrophysicist and mathematician and a member of the Hungarian Academy of Sciences. His primary research fields were astrophysics, nuclear physics, quantum mechanics, mathematical physics, and statistics, as well as electrodynamics and optics.

Biography Jánossy was the adopted son of influential Marxist philosopher and politician György Lukács (1885–1971). He was also the brother of the economist and engineer Ferenc Jánossy (1914–1997). He married the physicist Leonie Kahn (1913-1966) who he met during his studies in Berlin: together they were parents to physicists Mihály Jánossy (1942–2004), András Jánossy (1944), also a member of the Hungarian Academy of Sciences, and István Jánossy (1945), as well as Anna Jánossy (1938-1999), a medical researcher. After the 1919 fall of the early Hungarian Soviet Republic, his mother and stepfather, Gertrúd Borstieber and György Lukács, left the country together, and moved to Vienna. Thus, from the age of 6, Jánossy lived abroad: he attended university in Vienna and, later, in Berlin. He worked in the laboratory of Werner Kolhörster in Berlin (1934–1936) focusing on astrophysics until he and his wife had to move again, fleeing Nazism. He started working with P.M.S. Blackett — who became a Nobel laureate in 1948 — concentrating on cosmic radiation at Birkbeck College in London, heading the cosmic radiation research group and later at Manchester University. In 1947 invited by Walter Heitler and Erwin Schrödinger he joined the Dublin Institute for Advanced Studies as…Citește mai mult

Work At the beginning of his career in Germany, England, and Ireland, Jánossy focussed on cosmic rays, both experiment and theory. His name is linked to Geiger's coincidence detector development with special application to cosmic-ray secondary components created in the upper layers of the atmosphere (mesons such as kaons, muons, gamma rays). He demonstrated how primary cosmic rays colliding with the Earth's atmosphere produced secondary penetrating showers cascading to the surface of the earth (1940–1941). From an early age to his death, he had a wide-ranging interest in the mathematical and statistical aspects of physical analysis, and, in particular, the application of probability and calculus to experimental results in nuclear physics and particle physics. He is known for his statistical analysis methods for cosmic rays. Specifically, during his stay in Dublin, he completed his classic monograph on cosmic rays (1948) and published important monographs on particle showers (1950), introducing the eponymous joint probability densities—now called Jánossy densities—in the theory of random point processes. Until the 1950s, the most important field in the research of high-energy particles was the investigation of cosmic radiation. But as the large accelerators started to take over the leading role, Jánossy turned away from the investigation…Citește mai mult

Memberships and awards Member (1950) and, later, vice-president (1961 to 1973) of the Hungarian Academy of Sciences; member of the Bulgarian Academy of Sciences (1961), the Royal Irish Academy (1949), the Mongolian Academy of Sciences and the Academy of Sciences of the German Democratic Republic (1954). Awarded the Kossuth Prize (1951); Academic Gold Medal (1972); Vice chair of the Eötvös Physical Society (1950–1969); chair of the National Atomic Energy Commission. From 1966 till his death, president of the Hungarian Stamp Collectors' Association. The Eötvös Physical Society in 1994 established the Jánossy Lajos Award, for outstanding research in the field of theoretical and experimental physics.

Main works Cosmic Rays, Oxford, Clarendon Press, 1948, 424p. Online copy Cosmic Rays, Dublin, Dublin Institute for Advanced Studies, 1947, 56p. Cosmic rays and nuclear physics, London, Pilot Press, 1948, p. 186. English: cosmic radiation, Budapest, Educated People, 1954, p. 137. Italian: Raggi cosmici e fisica nucleare, Milano, Bompiani, 1954, p. 275. German: Einführung in die kosmische Strahlenforschung, Berlin, Deutscher Verlag der Wissenschaften, 1955, p. 148. Polish: Promienie kosmiczne, Warszawa, Wiedza Powszechna, 1956, p. 158, p. Bulgarian: Kosmični Lač Sofia, Akad, 1957, 141p. Russian: Kosmičeskie Luči, Moscow, 1949, 464p. Philosophical analysis of the special theory of relativity, Budapest, Central Research Institute of Physics, 1960, p. 76. English: Philosophical remarks on special relativity, Budapest, Central Research Institute for Physics, 1960, p. 62. Überlegungen zu den Grundlagen der Wahrscheinlchikeitsrechnung, Berlin, Akademie-Verlag, 1960, 23p. Reflections of the problem measuring the velocity of light, Budapest, Central Research Institute of Physics, 1963, p. 42. Nuclear Lexicon, chief editor: Jánossy Lajos, Budapest, Academic, 1963, p. 453. The relativity of philosophical problems, Budapest, Academic, 1963, p. 351 (Elek Tibor version) The problem of the Lorentzian relativity principle, explaining, ed. Theodore Siklos, Budapest, Central Research Institute for Physics, 1964, 47 p. Theory and practice of the evaluation of…Citește mai mult

Further reading Stephen Hajduska: Jánossy Lajos, in: Fizikai Szemle (1968) 9 p. 273–275. Pál, L. (1977). "L. Jánossy 1912–1978". Acta Physica Academiae Scientiarum Hungaricae. 43: I–. doi:10.1007/BF03157524. S2CID 123895005. Paul Francis Tétényi & Szabó Lajos Farewell Jánossy, in: Fizikai Szemle (1978) 3 p. 82–88. (bibliography) Charlemagne: "Jánossy Lajos", in Hungarian Science (1978) 9 p. 706–708. Somogyi Anthony, "Reflections on Lajos Jánossy's seventieth birth anniversary", in Hungarian Science (1982) 5 p. 391–396 In memoriam: Lajos Jánossy-75 Erwin Schrödinger-100, Budapest, Central Research Institute for Physics, 1987, p. 148 (MTA Ko ̈zponti Fizikai Kutato ́ Int ́ezete) ISBN 963-372-404-X. Tarjan Imre, Lajos Jánossy, Remembrance in: Fizikai Szemle (1987) 4 p. 121–122 Varga, Peter Jánossy Lajoss, demanding physicist

External links Lajos Jánossy Kardos István: Lételeme a fizika volt – Jánossy Lajos (1912–1978), in: Ezredvég Király Péter: Jánossy Lajos, a fizikus, in: Fizikai Szemle 2005. 8. sz. Palló Gábor: Jánossy Lajos műhelye, in: Fizikai Szemle 1991. 12. sz.