Universality laws for random matrices via exchangeable pairs

Abstract: Recently, Brailovskaya & van Handel (GAFA, 2024) established a suite of nonasymptotic universality laws which demonstrate that the spectral statistics of an independent sum of random matrices mirror the spectral statistics of a Gaussian random matrix with the same first- and second-order moments. This paper develops a more elementary proof of their main results by means of a new implementation of the method of exchangeable counterparts.