20th-century American physicists

Hans Albrecht Bethe (German pronunciation: [ˈhans ˈbeːtə] ; July 2, 1906 – March 6, 2005) was a German-American theoretical physicist who made major contributions to nuclear physics, astrophysics, quantum electrodynamics, and solid-state physics, and who won the 1967 Nobel Prize in Physics for his work on the theory of stellar nucleosynthesis. For most of his career, Bethe was a professor at Cornell University.During World War II, he was head of the Theoretical Division at the secret Los Alamos laboratory that developed the first atomic bombs. There he played a key role in calculating the critical mass of the weapons and developing the theory behind the implosion method used in both the Trinity test and the "Fat Man" weapon dropped on Nagasaki in August 1945.
After the war, Bethe also played an important role in the development of the hydrogen bomb, although he had originally joined the project with the hope of proving it could not be made. Bethe later campaigned with Albert Einstein and the Emergency Committee of Atomic Scientists against nuclear testing and the nuclear arms race. He helped persuade the Kennedy and Nixon administrations to sign, respectively, the 1963 Partial Nuclear Test Ban Treaty and 1972 Anti-Ballistic Missile Treaty (SALT I).
His scientific research never ceased and he was publishing papers well into his nineties, making him one of the few scientists to have published at least one major paper in his field during every decade of his career, which in Bethe's case spanned nearly seventy years. Freeman Dyson, once his doctoral student, called him the "supreme problem-solver of the 20th century".

Donald Arthur Glaser (September 21, 1926 – February 28, 2013) was an American physicist, neurobiologist, and the winner of the 1960 Nobel Prize in Physics for his invention of the bubble chamber used in subatomic particle physics.

Milton Spinoza Plesset (7 February 1908 – 19 February 1991) was an American applied physicist who worked in the field of fluid mechanics and nuclear energy. He was elected to the National Academy of Engineering in 1979 for his fundamental contributions to multiphase flows, bubble dynamics, and safety of nuclear reactors. Plesset served as professor of engineering science at California Institute of Technology during 1951 to 1978. Notable scientists Andrea Prosperetti, Norman Zabusky, and Chris Whipple finished their doctoral work under Plesset's guidance. Milton Plesset, Andrea Prosperetti, and Chris Whipple were elected to the National Academy of Engineering.
He with Christian Møller are known for the Møller–Plesset perturbation theory.
The Rayleigh-Plesset equation describing the dynamics of a bubble in an infinite body of fluid is also named after him.

Giovanni Rossi Lomanitz (10 October 1921 – 31 December 2002) was an American physicist.

Stanley Phillips Frankel (1919 – May, 1978) was an American computer scientist. He worked in the Manhattan Project and developed various computers as a consultant.

Sidney Michael Dancoff (September 27, 1913 in Philadelphia – August 15, 1951 in Urbana, Illinois) was an American theoretical physicist best known for the Tamm–Dancoff approximation method and for nearly developing a renormalization method for solving quantum electrodynamics (QED).

Gilbert Norman Plass (March 22, 1920 – March 1, 2004) was a Canadian physicist who in the 1950s made predictions about the increase in global atmospheric carbon dioxide (CO2) levels in the 20th century and its effect on the average temperature of the planet that closely match measurements reported half a century later.

Nicholas Monroe Smith Jr. (1914 – 2003) was a nuclear physicist and research consultant. Smith was an expert on reactor physics, a developer of operations research/computer modeling, and a computer applications consultant. He had ties to the Manhattan Project at Chicago and Oak Ridge, and worked with Samuel Allison and James Van Allen. Smith was a pioneer in the field of operations research.

Roy Walter Gould (April 25, 1927 – February 19, 2022) was an American electrical engineer and physicist who specialized in plasma physics. In 1959, he (together with Alvin Trivelpiece) was the first to describe electrostatic waves that were propagating at the boundary of a magnetized plasma column, now commonly known as Trivelpiece–Gould modes.Gould was elected a member of the National Academy of Engineering in 1971 for pioneering contributions to microwave electronics and plasma physics and distinguished service in higher education.

Donald Alfred Gurnett (April 11, 1940 – January 13, 2022) was an American physicist and professor at the University of Iowa who specialized in plasma physics.