From 1949 to 1984, Anderson was employed by
Bell Telephone Laboratories in
New Jersey, where he worked on a wide variety of problems in
condensed matter physics. During this period, he developed what is now called
Anderson localization (the idea that extended states can be localized by the presence of disorder in a system) and
Anderson's theorem (concerning impurity scattering in superconductors); invented the
Anderson Hamiltonian, which describes the site-wise interaction of electrons in a
transition metal; proposed
symmetry breaking within
particle physics (this played a role in the development of the
Standard Model and the development of the theory behind the
Higgs mechanism, which in turn generates
mass in some
elementary particles); created the pseudospin approach to the
BCS theory of
superconductivity; made seminal studies of
non-s-wave pairing (both symmetry-breaking and microscopic mechanism) in the superfluidity of
helium-3, and helped found the area of
spin-glasses. From 1967 to 1975, Anderson was a professor of theoretical physics at Cambridge. In 1977 Anderson was awarded the
Nobel Prize in Physics for his investigations into the electronic structure of magnetic and disordered systems, which allowed for the development of electronic switching and memory devices in computers. Co-researchers
Nevill Mott and
John Van Vleck shared the award with him. In 1982, he was awarded the
National Medal of Science. He retired from Bell Labs in 1984 and was Joseph Henry Professor Emeritus of Physics at
Princeton University. Anderson's writings included
Concepts in Solids,
Basic Notions of Condensed Matter Physics and
The Theory of Superconductivity in the High-Tc Cuprates. Anderson served on the board of advisors of
Scientists and Engineers for America, an organization focused on promoting sound science in American government. In response to the discovery of high-temperature superconductors in the 1980s, Anderson proposed
Resonating valence bond (RVB) theory to explain the phenomenon. While many found the idea unconvincing, RVB theory proved instrumental in the study of
spin liquids. Anderson also made conceptual contributions to the philosophy of science through his explication of
emergent phenomena, which became an inspiration for the science of complex systems. In 1972, he wrote an article called "More is Different" in which he emphasized the limitations of reductionism and the existence of hierarchical levels of science, each of which requires its own fundamental principles for advancement. In 1984, he participated in the founding workshops of the
Santa Fe Institute, a multidisciplinary research institute dedicated to the science of complex systems. Anderson also co-chaired the institute's 1987 conference on economics with
Kenneth Arrow and
W. Brian Arthur, and participated in its 2007 workshop on models of emergent behavior in complex systems. In 1987, Anderson testified to the US Congress, "against the construction of the
Superconducting Super Collider (SSC), a 40 TeV proton-proton collider in Texas that would have been the biggest experiment in particle physics. Anderson's opposition to the SSC did not directly lead to its cancellation in 1993—spiralling costs were the main factor—but he was perhaps its most high-profile opponent." He was, "skeptical of the supposed boost it would provide to science in the US and the claim that the spin-offs would provide great return on investment." A 2006 statistical analysis of scientific research papers by José Soler, comparing the number of references in a paper to the number of citations, declared Anderson to be the "most creative" amongst ten most cited physicists in the world. In 2021, Oxford University Press published the biography
A Mind over Matter: Philip Anderson and the Physics of the Very Many by Andrew Zangwill. == Personal life ==