Rudolf Peierls

Born in Berlin to an assimilated Jewish family, Peierls left Germany after Hitler's rise and became a leading physicist in Britain. In 1940, with Otto Frisch, he wrote the Frisch–Peierls memorandum, the first calculation showing that a practical atomic bomb could be built from a small mass of uranium-235 — a document that galvanized the Allied nuclear programs. He also made lasting contributions to solid-state and condensed-matter theory, and later became a prominent advocate for nuclear arms control.