Oskar Klein
Oskar Benjamin Klein (Swedish: [ˈklajn]; 15 September 1894 – 5 February 1977) was a Swedish theoretical physicist now best remembered for the Klein-Gordon equation of relativistic quantum mechanics, the Kaluza-Klein theory, a unified field theory of gravitation and electromagnetism, and the Klein–Nishina cross section in quantum electrodynamics. == Biography == Klein was born in Danderyd outside Stockholm, son of the chief rabbi of Stockholm, Gottlieb Klein from Humenné in Kingdom of Hungary, now Slovakia and Antonie (Toni) Levy.