Low-Energy Effective Field Theory

Low-Energy Effective Field Theory (LEEFT) is a framework in physics that allows scientists to describe complex phenomena using simpler, approximate models. When dealing with systems where certain energy scales are much lower than the inherent energy scales of the fundamental theory (like quantum mechanics or particle physics), LEEFT focuses only on the relevant degrees of freedom at that lower energy. This means it simplifies calculations by ignoring less significant effects, making predictions easier and often sufficient for practical applications, such as in condensed matter physics or cosmology, while still being consistent with the underlying theories.