Heidelberg 2022 – wissenschaftliches Programm

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AGPhil: Arbeitsgruppe Philosophie der Physik

AGPhil 4: Gravitational and Electromagnetic Waves

AGPhil 4.3: Vortrag

Dienstag, 22. März 2022, 15:15–15:45, AGPhil-H14

Absorbing the Arrow of Electromagnetic Radiation — Mario Hubert and •Charles Sebens — California Institute of Technology, Pasadena, CA, USA

We argue that the asymmetry between diverging and converging electromagnetic waves is just one of many asymmetries in observed phenomena that can be explained by a past hypothesis and statistical postulate (together assigning probabilities to different states of matter and field in the early universe). The arrow of electromagnetic radiation is thus absorbed into a broader account of temporal asymmetries in nature. We give an accessible introduction to the problem of explaining the arrow of radiation and compare our preferred strategy for explaining the arrow to three alternatives: (i) modifying the laws of electromagnetism by adding a radiation condition requiring that electromagnetic fields always be attributable to past sources, (ii) removing electromagnetic fields and having particles interact directly with one another through retarded action-at-a-distance, (iii) adopting the Wheeler-Feynman approach and having particles interact directly through half-retarded half-advanced action-at-a-distance. In addition to the asymmetry between diverging and converging waves, we also consider the related asymmetry of radiation reaction.