Hans Albrecht Bethe (German pronunciation: [ˈhans ˈalbʁɛçt ˈbeːtə]; July 2, 1906 – March 6, 2005) was a German-American nuclear physicist, and Nobel laureate in physics for his work on the theory of stellar nucleosynthesis. A versatile theoretical physicist, Bethe also made important contributions to quantum electrodynamics, nuclear physics, solid-state physics and astrophysics. During World War II, he was head of the Theoretical Division at the secret Los Alamos laboratory which developed the first atomic bombs. There he played a key role in calculating the critical mass of the weapons, and did theoretical work on the implosion method used in both the Trinity test and the "Fat Man" weapon dropped on Nagasaki, Japan. For most of his career, Bethe was a professor at Cornell University.

During the early 1950s, Bethe also played an important role in the development of the larger hydrogen bomb, though he had originally joined the project with the hope of proving it could not be made. Bethe later campaigned together with Albert Einstein in the Emergency Committee of Atomic Scientists against nuclear testing and the nuclear arms race. He influenced the White House to sign the ban of atmospheric nuclear tests in 1963 and the 1972 Anti-Ballistic Missile Treaty, SALT I. His scientific research never ceased even into the later years of his life and he was publishing papers well into his nineties. He is one of the few scientists who can claim a major paper in his field every decade of his career, which spanned nearly 70 years. Freeman Dyson called Bethe the "supreme problem solver of the 20th century."

Freeman John Dyson FRS (born December 15, 1923) is a British-born American theoretical physicist and mathematician, famous for his work in quantum electrodynamics, solid-state physics, astronomy and nuclear engineering. Dyson is a member of the Board of Sponsors of the Bulletin of the Atomic Scientists. Dyson has lived in Princeton, New Jersey, for over fifty years.

Dyson's father was the English composer Sir George Dyson; his mother was trained as a lawyer but after Dyson was born worked as a social worker. Despite sharing a last name, he is not related to the early 20th century astronomer Frank Watson Dyson, but as a small boy Freeman Dyson was aware of Frank Watson Dyson. Freeman credits the popularity of an astronomer with the same last name as having inadvertently helped to spark his interest in science.^{[citation needed]}

Dyson has six children, two of them (Esther and George) with his first wife, mathematician Verena Huber-Dyson, and the other four with his second wife, Imme Dyson, a masters runner who married him in 1958. Due to issues with some of his children not being recognized as British citizens he abjured his allegiance to Britain, and became a naturalized American citizen.

Richard Phillips Feynman ( /ˈfaɪnmən/; May 11, 1918 – February 15, 1988) was an American physicist known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, and the physics of the superfluidity of supercooled liquid helium, as well as in particle physics (he proposed the parton model). For his contributions to the development of quantum electrodynamics, Feynman, jointly with Julian Schwinger and Sin-Itiro Tomonaga, received the Nobel Prize in Physics in 1965. He developed a widely used pictorial representation scheme for the mathematical expressions governing the behavior of subatomic particles, which later became known as Feynman diagrams. During his lifetime, Feynman became one of the best-known scientists in the world. In a 1999 poll of 130 leading physicists worldwide by the British journal Physics World he was ranked as one of the ten greatest physicists of all time.

He assisted in the development of the atomic bomb and was a member of the panel that investigated the Space Shuttle Challenger disaster. In addition to his work in theoretical physics, Feynman has been credited with pioneering the field of quantum computing, and introducing the concept of nanotechnology. He held the Richard Chace Tolman professorship in theoretical physics at the California Institute of Technology.