(1922–    ), Danish physicist and Nobel laureate, the son of physicist Niels Bohr. Born on June 19, 1922, in Copenhagen, he began his studies in physics at the University of Copenhagen in 1940. For two years (1943–45) during World War II he assisted his father on the atomic bomb project at Los Alamos, N.Mex. He completed his studies in 1946 and then joined the Institute for Theoretical Physics in Copenhagen, devoting his attention to the inner structure of the atom (see Atom and Atomic Theory). He spent a semester in 1948 at the Institute for Advanced Study in Princeton. In 1949–50 he did research at Columbia University, where he met the American physicist James L. Rainwater, who was about to propose his findings on a new model for the structure of the atomic nucleus.

Soon after returning to Denmark, Bohr started his collaboration with the U.S. physicist Ben R. Mottelson, which led to their fundamental discovery that was known as the collective motion theory of the atomic nucleus. They published their findings in a 3-paper series in 1952–53. Bohr's doctoral thesis (1954) at the University of Copenhagen also dealt with this theory, which helped to explain many nuclear properties by showing that nuclear particles can vibrate and rotate so as to distort the shape of the nucleus from the expected spherical symmetry into an ellipsoid.

In 1963, Bohr became director of the Institute for Theoretical Physics in Copenhagen (renamed the Niels Bohr Institute in 1965, in honor of his father who had died in 1962). He resigned in 1970 to devote more time to research.

In 1975, Bohr, Mottelson, and Rainwater received the Nobel Prize in physics for “the discovery of the connection between collective motion and particle motion in atomic nuclei and the development of the theory of the structure of the atomic nucleus based on this connection.”

From 1975 to 1981 he was director of the Nordic Institute for Theoretical Physics, which shares research and facilities with the Niels Bohr Institute. Bohr and Mottelson coauthored a 2-volume monograph titled Single-Particle Motion (vol. 1, 1969) and Nuclear Deformations (vol. 2, 1975).

See also Elementary Particles.