 Effective field theory of large-scale structure

The effective field theory of large-scale structure describes long-wavelength matter dynamics while representing unresolved short-scale motion through an effective stress tensor. It supplements standard perturbation theory in cosmology with symmetry-allowed terms whose coefficients can be calibrated from simulations or data. A leading correction scales as $k^2{\delta }^{(1)}$. Its role is to account for short-scale influence on long-scale predictions, not to resolve individual collapsed objects.^[ref]