Folk theorem (physics)

For other uses, see Folk theorem (disambiguation).

In theoretical physics, the folk theorem states how to construct an effective field theory. It was first formulated by Steven Weinberg in the 1979 in the context of quantum chromodynamics and the origin of nuclear forces. It is a "folk theorem" in the sense that is a motivated conjecture, with no rigorous proof, but expected to be valid. It states that the most general Lagrangian that is consistent with the symmetries of the underlying theory can be rendered into an effective field theory at low energies that respects the symmetries and its well-behaved.

The theorem has been credited for motivating the development of the chiral perturbation theory in the 1980s. It was first used to calculate processes involving soft pions (low energy pions).

This article is issued from Wikipedia. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.