Willis Eugene Lamb Jr. (; July 12, 1913 – May 15, 2008) was an American physicist who won the Nobel Prize in Physics in 1955 "for his discoveries concerning the fine structure of the hydrogen spectrum." The Nobel Committee that year awarded half the prize to Lamb and the other half to Polykarp Kusch, who won "for his precision determination of the magnetic moment of the electron."  Lamb was able to precisely determine a surprising shift in electron energies in a hydrogen atom (see Lamb shift).  Lamb was a professor at the University of Arizona College of Optical Sciences.