Hans Bethe

Hans Bethe
Hans Bethe in 1966
Born	(1906-07-02)2 July 1906 Strasbourg, Alsace-Lorraine, German Empire
Died	6 March 2005(2005-03-06) (aged 98) Ithaca, New York, United States
Nationality	German-American
Citizenship	United States
Alma mater	University of Munich
Known for	Bethe formula, Bethe–Salpeter equation, Bethe–Weizsäcker cycle
Awards	Nobel Prize in Physics (1967) Enrico Fermi Award (1961) National Medal of Science (1975)
Scientific career
Fields	Physics
Institutions	Cornell University
Doctoral advisor	Arnold Sommerfeld
Doctoral students	Freeman Dyson, Richard Feynman

Hans Albrecht Bethe (July 2, 1906 – March 6, 2005) was a German-American nuclear physicist who made significant contributions to quantum electrodynamics, nuclear physics, and astrophysics. He was awarded the Nobel Prize in Physics in 1967 for his work on the theory of stellar nucleosynthesis.

Early Life and Education

Hans Bethe was born in Strasbourg, then part of the German Empire. He studied at the University of Munich, where he completed his PhD under the supervision of Arnold Sommerfeld in 1928. His early work focused on quantum mechanics and solid-state physics.

Career and Research

After completing his education, Bethe held academic positions in Germany until the rise of the Nazi Party forced him to emigrate. He moved to the United States in 1935 and joined the faculty at Cornell University, where he remained for the rest of his career.

During World War II, Bethe was a key figure in the Manhattan Project, working on the development of the atomic bomb at Los Alamos National Laboratory. His contributions to the project included the development of the Bethe formula for the stopping power of charged particles and the Bethe–Salpeter equation for bound states in quantum field theory.

Stellar Nucleosynthesis

Bethe's most famous work is his theory of stellar nucleosynthesis, which describes the nuclear processes that power stars. His research on the Bethe–Weizsäcker cycle explained how stars convert hydrogen into helium, releasing energy in the process. This work earned him the Nobel Prize in Physics in 1967.

Later Years and Legacy

After the war, Bethe continued to work on both theoretical and applied physics. He was a strong advocate for the peaceful use of nuclear energy and played a significant role in the development of nuclear policy in the United States. He received numerous awards and honors, including the Enrico Fermi Award in 1961 and the National Medal of Science in 1975.

Bethe remained active in research and public policy until his death in 2005 in Ithaca, New York. His contributions to physics have had a lasting impact on the field, and he is remembered as one of the most influential physicists of the 20th century.

See Also

• Quantum electrodynamics
• Nuclear physics
• Astrophysics
• Manhattan Project
• Stellar nucleosynthesis