Hans Bethe (1906-2005) was a German-born theoretical physicist who immigrated to the United States when Adolf Hitler rose to power.
He investigated the source of solar energy, which led him to make discoveries about the process of fusion. He joined the Manhattan Project, where he served as the chief of the theoretical division. His expertise was in the theory of atomic nuclei having helped develop a theory of the deuteron in 1934. He also derived theory relating to nuclear reactions such that he could predict many reaction cross sections.
After World War II ended, Bethe worked with Edward Teller to help develop the hydrogen bomb. But he also helped negotiate the 1963 partial test ban treaty with the Soviet Union, and advised several Democratic presidents. Late in life Bethe advocated against the development of defensive nuclear systems.
When Hans Bethe died, the whole October issue of Physics Today - the membership journal of the American Institute of Physics - was dedicated to articles on his life and his achievements. Here, for instance, Freeman Dyson wrote:
- The confirmation of QED as the most precisely tested of all the laws of nature is one of the great triumphs of 20th-century science. We owe this triumph chiefly to the vision of two men, Willis Lamb and Hans Bethe.