Anderson, Philip Warren (1923-...), an American theoretical physicist, studied the physical properties of solid and liquid materials. This field of physics is called solid-state physics, or condensed-matter physics (see Solid-state physics). Anderson carried out fundamental work on theories of the electronic distribution of magnetic materials. He also studied disordered systems, materials in which the atoms are not arranged in definite patterns. His work improved scientists' understanding of how electric currents flow in noncrystalline materials (those without a regular atomic structure) as well as in superconductors--materials that lose all resistance to the flow of current at low temperatures (see Crystal; Electronics; Superconductivity). In 1977, Anderson was awarded the Nobel Prize for physics, sharing the prize with Sir Nevill Mott of the United Kingdom and John H. Van Vleck of the United States (see Mott, Sir Nevill; Van Vleck, John Hasbrouck).