German crystallographer and physicist, noted as a pioneer of X-ray diffraction methods. Ewald was the eponym of Ewald construction and the Ewald sphere, both useful constructs in the field.
Ewald received his early education in the classics at the Gymnasium in Berlin and Potsdam, where he learned to speak Greek, French, and English, in addition to his native language of German.
Ewald began his higher education in physics, chemistry, and mathematics at Gonville and Caius College in Cambridge, during the winter of 1905. Then in 1906 and 1907 he continued his formal education at the University of Göttingen, where his interests turned primarily to mathematics. Ewald was taken on by David Hilbert as a scribe. In 1907, he continued his mathematical studies at the Ludwig Maximilian University of Munich (LMU), under Arnold Sommerfeld at his Institute for Theoretical Physics. He was granted his doctorate in 1912. His doctoral thesis developed the laws of propagation of X-rays in single crystals. After earning his doctorate, he was an assistant to Sommerfeld.
During World War I, Ewald served in the German military as a medical technician. When he could, he continued to think about the physics of his doctoral thesis, and he developed the dynamical theory of X-ray diffraction, which he was later to use in his Habilitationsschrift. At the conclusion of the war, he returned to LMU as an assistant to Sommerfeld. He completed his Habilitation in 1917, and became a Privatdozent there, while remaining as an assistant to Sommerfeld.
In 1921, while still at LMU, Ewald published a paper on the theta function method of analyzing dipole fields in crystals, an offshoot from his earlier work on the dynamical theory of optics and X-rays in crystals, which appeared in three journal publications. Ewald, was having trouble subtracting out of his calculations the field of the test dipole. The solution was provided by Sommerfeld’s assistant and former doctoral student, Peter Debye, in a discussion that took no more than 15 minutes. Ewald’s paper has been widely cited in the literature as well as scientific books, such as Dynamical Theory of Crystal Lattices by Max Born and Kun Huang.
Paul Peter Ewald died on 22 August 1985 at age 97 in Ithaca, New York.
Link to Wikipedia biography