Who has won the Nobel Prize in the same category twice?
Frederick Sanger Frederick Sanger ( ; 13 August 1918 – 19 November 2013) was a British biochemist who twice won the Nobel Prize in Chemistry, one of only two people to have done so in the same category (the other is John Bardeen in physics), the fourth person overall with , and the third person overall with two Nobel Prizes in the sciences. In 1958, he was awarded a Nobel Prize in chemistry "for his work on the structure of proteins, especially that of insulin". In 1980, Walter Gilbert and Sanger shared half of the chemistry prize "for their contributions concerning the determination of base sequences in nucleic acids". The other half was awarded to Paul Berg "for his fundamental studies of the biochemistry of nucleic acids, with particular regard to recombinant DNA".
Julian Schwinger Julian Seymour Schwinger (February 12, 1918 – July 16, 1994) was a Nobel Prize winning American theoretical physicist. He is best known for his work on the theory of quantum electrodynamics (QED), in particular for developing a relativistically invariant perturbation theory, and for renormalizing QED to one loop order. Schwinger was a physics professor at several universities.