2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/147495This article is intended to provide a pedagogical introduction to the supersymmetry method for performing ensemble-averaging in Gaussian random-matrix theory. The method is illustrated by a detailed calculation of the simplest non-trivial physical quantity, namely, the second-order correlation in the density of states for two different energies within the spectrum (commonly known as the density-density correlator) for a system described by a random Hamiltonian matrix belonging to the Gaussian unitary ensemble.36 pages, LaTeX, No figures. New address for correspondence. Some misprints corrected and background material added.Condensed MatterHigh Energy Physics - Theorytext