Oliver Penrose FRS, FRSE (born 1929) is a British theoretical physicist.[1]

He is the son of the scientist Lionel Penrose, brother of the mathematical physicist Roger Penrose, and brother of chess master Jonathan Penrose.[2][3]

He was associated for seventeen years with the Open University, and was a Professor of Mathematics at Heriot-Watt University in Edinburgh from 1986 until his retirement in 1994. He holds the title of Professor Emeritus at Heriot-Watt, and remains active in research there. His areas of interest include statistical mechanics,[4] phase transitions in metals, and physical chemistry of surfactants. He is particularly known for the concept of off-diagonal long-range order, which is central to our present-day understanding of superfluids and superconductors. Other more abstract topics in which he has worked include understanding the physical basis for the direction of time and interpretations of quantum mechanics.[