Parisi measure of the Sherrington-Kirkpatrick model with external field

Abstract

We prove that the Parisi measure of the Sherrington-Kirkpatrick model has connected support at every positive temperature and every positive external field. When the model breaks replica symmetry, its support is an interval contained in $(0,1)$, its restriction to the interior has a smooth density that remains strictly positive up to both endpoints, and both endpoints carry atoms. The proof rests on a strict inequality for moments of spatial derivatives of the Parisi PDE, which both excludes gaps in the support and forces positivity of the density. The same estimates recover the zero-field support description and give a lower bound for the mass of its upper atom.

arXiv comment46 pages