Dennis Lehmkuhl (University of Bonn)

Title: Penrose’s analogy between different types of spacetime curvature and optical lenses

Abstract: In a paper published in 1965 but written to a large extent in 1960 and 1961, Roger Penrose suggested a far-reaching link between the two types of spacetime curvature (Ricci curvature and Weyl curvature) on the one hand and different types of optical lenses (astigmatic and anastigmatic lenses) on the other hand. This talk will analyse a.) the historical context and genesis of this paper, b.) what type of analogy Penrose established between curvature and lenses, c.) how far-reaching the analogy is (i.e. how big the set of spacetimes is to which it applies) and d.) what role the resulting idea that the presence of Ricci curvature can lead to a focusing of light rays played in Penrose’s first singularity theorem of 1965.

Dennis Lehmkuhl