Linear Statistics of Matrix Ensembles in Classical Background

Abstract: Given a joint probability density function of $N$ real random variables, ${x_j}{j=1}^{N},$ obtained from the eigenvector-eigenvalue decomposition of $N\times N$ random matrices, one constructs a random variable, the linear statistics, defined by the sum of smooth functions evaluated at the eigenvalues or singular values of the random matrix, namely, $\sum{j=1}^{N}F(x_j).$ For the jpdfs obtained from the Gaussian and Laguerre ensembles, we compute, in this paper the moment generating function $\mathbb{E}{\beta}({\rm exp}(-\lambda\sum{j}F(x_j))),$ where $\mathbb{E}_{\beta}$ denotes expectation value over the Orthogonal ($\beta=1$) and Symplectic ($\beta=4)$ ensembles, in the form one plus a Schwartz function, none vanishing over $\mathbb{R}$ for the Gaussian ensembles and $\mathbb{R}^+$ for the Laguerre ensembles. These are ultimately expressed in the form of the determinants of identity plus a scalar operator, from which we obtained the large $N$ asymptotic of the linear statistics from suitably scaled $F(\cdot).$