Ivar Waller (born 11.06.1898) - Swedish theoretical physicist, a member of the Royal Swedish Academy of Sciences. Born in Flen. He graduated from Uppsala University (1922) and worked there in 1925–64 (from 1934 professor and director of the university's Institute of Theoretical Physics).
His research concerned solid-state physics, nuclear physics and quantum electrodynamics.
He studied the scattering of slow neutrons and of X-rays by crystals, the moderation of neutrons and the scattering of nucleons by nuclei. He proposed (1932) a theory of the spin-spin dipole interaction in paramagnets and showed that energy can be transferred between the magnetic and the phonon systems because the dipole energy is modulated by the vibrations of the lattice. Starting from Dirac's theory, he calculated (1930) the self-energy of the electron and showed that it diverges quadratically.
In 1945–71 a member of the Nobel Committee for Physics.