Pethick studied at the
University of Oxford, where he received his BA in 1962 and his PhD in 1965. He was then a postdoc at
Magdalen College, Oxford and at the
University of Illinois at Urbana-Champaign, where he was an associate professor from 1970 to 1973, a full professor from 1973 to 1995, and an adjunct professor from 1995 to 1998. For two academic years from 1970 to 1972 he was a
Sloan Research Fellow. He then worked, until his retirement, at the
Niels Bohr Institute in Copenhagen (with which Nordita was closely associated before moving to Stockholm). He was for the academic year 1973–1974 a visiting researcher at Moscow's
Landau Institute for Theoretical Physics and in 1995 a visiting scientist at the Institute for Nuclear Theory (INT), located in Seattle on the campus of the
University of Washington. (
Gordon Baym and
Tin-Lun Ho also won the Onsager Prize for 2008.) In 2011 Pethick received the
Hans A. Bethe Prize for "fundamental contributions to the understanding of nuclear matter at very high densities, the structure of neutron stars, their cooling, and the related neutrino processes and astrophysical phenomena." In 2015 he was awarded the
Feenberg Medal "for his pioneering contributions and profound insights into many-body physics across diverse physical systems, ranging from ultracold atoms and quantum liquids to dense nuclear matter in neutron stars and stellar collapse". In 2013 he was elected an honorary foreign member of the
American Academy of Arts and Sciences. Pethick is since 1977 a member of the
Royal Danish Academy of Sciences and Letters and since 2003 a member of the
Norwegian Academy of Language and Literature. In 1985 he was elected a Fellow of the
American Physical Society for "his extensive contributions to the theory of condensed matter systems, ranging from low temperature helium and superconductors to condensed astrophysical objects and nuclear matter." In 2016 he was elected a member of the
American Philosophical Society. He initiated the tradition of making tea at the
Niels Bohr Institute everyday at 15:30 with cake. He is still doing this to this day. ==Selected publications==