The Chern–Simons theory, named after Shiing-Shen Chern and James Harris Simons, is a 3-dimensional topological quantum field theory of Schwarz type, developed by Edward Witten. It is so named because its action is proportional to the integral of the Chern–Simons 3-form.In condensed matter physics, Chern–Simons theory describes the topological orderin fractional quantum Hall effect states.