arXiv subjects

Johannes Grebe-Ellis

Publications and source records attributed to Johannes Grebe-Ellis.

4 recordsLinked to original sources

arXiv2018

Pitfalls in the teaching of elementary particle physics

Elementary particle physics is gradually implemented into science curricula at high school level. However, common presentations on educational, semi-technical or popular level contain or support severe misconceptions. We discuss in particular the notion of `particle', the interaction between them and the use of Feynman diagrams. In many cases the true novelty of particle physics (i.e. quantum field theory) is largely ignored. We also suggest reasons for this widespread distortions of particle physics in popular accounts.

physics.ed-ph↗

arXiv2017

Power Area Density in Inverse Spectra

In recent years, inverse spectra were investigated with imaging optics and a quantitative description with radiometric units was suggested (Rang 2015). It could be shown that inverse spectra complement each other additively to a constant intensity level. Since optical intensity in radiometric units is a power area density, it can be expected that energy densities of inverse spectra also fulfill an inversion equation and complement each other. In this contribution we report findings on a measurement of the power area density of inverse spectra for the near ultraviolet, visible and the infrared spectral range. They show the existence of corresponding spectral regions ultra-yellow (UY) and infra-cyan (IC) in the inverted spectrum and thereby present additional experimental evidence for equivalence of inverse spectra beyond the visible range.

physics.optics↗

arXiv2017

Planck's radiation law, the light quantum, and the prehistory of indistinguishability in the teaching of quantum mechanics

Planck's law for black-body radiation marks the origin of quantum theory and is discussed in all introductory (or advanced) courses on this subject. However, the question whether Planck really implied quantisation is debated among historians of physics. We present a simplified account of this debate which also sheds light on the issue of indistinguishability and Einstein's light quantum hypothesis. We suggest that the teaching of quantum mechanics could benefit from including this material beyond the question of historical accuracy.

physics.hist-ph↗

arXiv2016

Note on the classification of super-resolution in far-field microscopy and information theory

In recent years several far-field microscopy techniques have been developed which manage to overcome the diffraction limit of resolution. A unifying classification scheme for them is clearly desirable. We argue that existing schemes based on the information capacity of the optical system can not easily be extended to cover e.g., STED microscopy or techniques based on single molecule imaging. We suggest a classification based on a reconstruction of the Abbe limit.

physics.optics↗