2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/159600We discuss the emergence of symmetry-breaking {\it via} the Pomeranchuk instability from interactions that respect the underlying point-group symmetry. We use a variational mean-field theory to consider a 2D continuum and a square lattice. We describe two experimental signatures: a symmetry-breaking pattern of Friedel oscillations around an impurity; and a structural transition.corrected typos, added and updated references, better-resolution figuresStrongly Correlated Electronstext