From aether impulse to QED: Sommerfeld and the Bremsstrahlen theory

NASA Astrophysics Data System (ADS)

Eckert, Michael

2015-08-01

The radiation that is due to the braking of charged particles has been in the focus of theoretical physics since the discovery of X-rays by the end of the 19th century. The impact of cathode rays in the anti-cathode of an X-ray tube that resulted in the production of X-rays led to the view that X-rays are aether impulses spreading from the site of the impact. In 1909, Arnold Sommerfeld calculated from Maxwell's equations the angular distribution of electromagnetic radiation due to the braking of electrons. He thereby coined the notion of "Bremsstrahlen." In 1923, Hendrik A. Kramers provided a quantum theoretical explanation of this process by means of Bohr's correspondence principle. With the advent of quantum mechanics the theory of bremsstrahlung became a target of opportunity for theorists like Yoshikatsu Sugiura, Robert Oppenheimer, and-again-Sommerfeld, who presented in 1931 a comprehensive treatise on this subject. Throughout the 1930s, Sommerfeld's disciples in Munich and elsewhere extended and improved the bremsstrahlen theory. Hans Bethe and Walter Heitler, in particular, in 1934 presented a theory that was later regarded as "the most important achievement of QED in the 1930s" (Freeman Dyson). From a historical perspective the bremsstrahlen problem may be regarded as a probe for the evolution of theories in response to revolutionary changes in the underlying principles.

List of participants at SIDE IV meeting, Tokyo, 27 November--1 December 2000

NASA Astrophysics Data System (ADS)

2001-12-01

Mark J Ablowitz, Vsevolod Adler, Mark Alber, Said Belmehdi, Marco Boiti, Claude Brezinski, R Bullough, Y M Chiang, Theodore Chihara, Peter A Clarkson, Robert Conte, Adam Doliwa, Vladimir Dorodnitsyn, Mitsuaki Eguchi, Claire Gilson, Basil Grammaticos, Valeri Gromak, Rod Halburd, Koji Hasegawa, Jarmo Hietarinta, Ryogo Hirota, Xing Biao Hu, M Idzumi, J Inoguchi, Hiroya Ishikara, Mourad Ismail, Shin Isojima, Kenichi Ito, Yoshiaki Itoh, Masashi Iwasaki, Klara Janglajew, Michio Jimbo, Nalini Joshi, Kenji Kajiwara, Saburo Kakei, Masaru Kamata, Satoshi Kamei, Rinat Kashaev, Shingo Kawai, Taeko Kimijima, K Kimura, Anatol Kirillov, Koichi Kondo, Boris Konopelchenko, Martin Kruskal, Atsuo Kuniba, Wataru Kunishima, Franklin Lambert, Serguei Leble, Decio Levi, Shigeru Maeda, Manuel Manas, Ken-Ichi Maruno, Tetsu Masuda, J Matsukidaira, Atsushi Matsumiya, Shigeki Matsutani, Yukitaka Minesaki, Mikio Murata, Micheline Musette, Atsushi Nagai, Katsuya Nakagawa, Atsushi Nakamula, Akira Nakamura, Yoshimasa Nakamura, Frank Nijhoff, J J C Nimmo, Katsuhiro Nishinari, Michitomo Nishizawa, A Nobe, Masatoshi Noumi, Yaeko Ohsaki, Yasuhiro Ohta, Kazuo Okamoto, Alexandre Orlov, Naoki Osada, Flora Pempinelli, Spiro Pyrlis, Reinout Quispel, Orlando Ragnisco, Alfred Ramani, Jean-Pierre Ramis, Andreas Ruffing, Simon Ruijsenaars, Satoru Saito, Noriko Saitoh, Hidetaka Sakai, Paulo Santini, Narimasa Sasa, Ryu Sasaki, Yoshikatsu Sasaki, Junkichi Satsuma, Sergei Sergeev, Nobuhiko Shinzawa, Evgueni Sklyanin, Juris Suris, Norio Suzuki, Yukiko Tagami, Katsuaki Takahashi, Daisuke Takahashi, Tomoyuki Takenawa, Yoshiro Takeyama, K M Tamizhmani, T Tamizhmani, Kouichi Toda, Morikatsu Toda, Tetsuji Tokihiro, Takayuki Tsuchida, Yohei Tsuchiya, Teruhisa Tsuda, Satoru Tsujimoto, Walter Van Assche, Claude Viallet, Luc Vinet, Shinsuke Watanabe, Yoshihida Watanabe, Ralph Willox, Pavel Winternitz, Yasuhiko Yamada, Yuji Yamada, Jin Yoneda, Haruo Yoshida, Katsuhiko Yoshida, Daisuke Yoshihara, Fumitaka Yura, J

Shedding Light on the Cosmic Skeleton

NASA Astrophysics Data System (ADS)

2009-11-01

, and have identified several groups of galaxies surrounding the main galaxy cluster. They could distinguish tens of such clumps, each typically ten times as massive as our own Milky Way galaxy - and some as much as a thousand times more massive - while they estimate that the mass of the cluster amounts to at least ten thousand times the mass of the Milky Way. Some of the clumps are feeling the fatal gravitational pull of the cluster, and will eventually fall into it. "This is the first time that we have observed such a rich and prominent structure in the distant Universe," says Tanaka. "We can now move from demography to sociology and study how the properties of galaxies depend on their environment, at a time when the Universe was only two thirds of its present age." The filament is located about 6.7 billion light-years away from us and extends over at least 60 million light-years. The newly uncovered structure does probably extend further, beyond the field probed by the team, and hence future observations have already been planned to obtain a definite measure of its size. More information This research was presented in a paper published as a letter in the Astronomy & Astrophysics Journal: The spectroscopically confirmed huge cosmic structure at z = 0.55, by Tanaka et al. The team is composed of Masayuki Tanaka (ESO), Alexis Finoguenov (Max-Planck-Institute for Extraterrestrial Physics, Garching, Germany and University of Maryland, Baltimore, USA), Tadayuki Kodama (National Astronomical Observatory of Japan, Tokyo, Japan), Yusei Koyama (Department of Astronomy, University of Tokyo, Japan), Ben Maughan (H.H. Wills Physics Laboratory, University of Bristol, UK) and Fumiaki Nakata (Subaru Telescope, National Astronomical Observatory of Japan). ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, the Czech

Evidence for Ultra-Energetic Particles in Jet from Black Hole

NASA Astrophysics Data System (ADS)

2006-06-01

shoot out from the black hole at close to the speed of light and then release their energy as radiation as far out as they are seen, the particles have to be accelerated locally, where they produce their emission. Both teams also used data from the third of NASA's Great Observatories, the Hubble Space Telescope, and the radio telescopes of the Very Large Array (VLA). The three space telescopes and the VLA "see" emission of different wavelengths from celestial objects, and the combined data was essential to reveal the new comprehensive perspective on the jets. "The new observations show that the flow structure of this jet is more complicated than had been assumed previously," Jester explains. "That the present evidence favors the synchrotron model deepens the mystery of how jets produce the ultra-energetic particles that radiate at X-ray wavelengths." "Our results call for a radical rethink of the physics of relativistic jets that black holes drive," said Uchiyama. "But, we now have a crucial new clue to solving one of the major mysteries in high-energy astrophysics." Other authors on the papers include Jeffrey Van Duyne and Paolo Coppi at Yale; C.C. Cheung at Stanford University; Rita Sambruna at NASA/GSFC, Greenbelt, MD; Tadayuki Takahashi at ISAS/JAXA, Japan; Laura Maraschi and Fabrizio Tavecchio at the Osservatorio Astronomico di Brera, Milan; Dan Harris from the SAO; Herman Marshall at MIT; and Klaus Meisenheimer at Max Planck Institute for Astronomy in Heidelberg. Grant and contract funding from NASA supported the research. Additional images and background material are available at: http://www.astro.soton.ac.uk/~jester/3C273.html and http://www.astro.isas.jaxa.jp/~uchiyama/Site2/Spitzer_3C273.html