Brian David Josephson is a Welsh physicist, born on January 4, 1940, in Cardiff, Wales. He became a prominent figure in the world of theoretical physics and is best known for his groundbreaking work on superconductivity, for which he was awarded the Nobel Prize in Physics in 1973.
His major contribution to science came with the discovery of the "Josephson Effect," which describes the quantum mechanical phenomenon of supercurrents tunneling through a thin insulating barrier between two superconductors. This discovery has had significant implications in various fields, including quantum computing and precision measurement technologies.