John Schrieffer. Historical portrait of the US physicist John Robert Schrieffer (born 1931). He researched his PhD thesis on superconductivity at Illinois University, USA, under the supervision of Bardeen. Collaboration with Bardeen and Cooper led to the BCS (Bardeen-Cooper-Schrieffer) theory of superconductivity in 1957. This theory uses pairs of electrons (Cooper pairs) to explain the zero- resistance phenomenon known as superconductivity. Schrieffer used a statistical approach to find a quantum mechanical wave function that extended the single pair properties to solids containing many pairs. He shared the 1972 Nobel Prize for Physics with Bardeen and Cooper.