NAME: K. A. Muttalib ADDRESS: Physics Dept. University of Florida New Physics Building P.O. Box 118440 EMAIL ADDRESS: muttalib@phys.ufl.edu TITLE OF TALK: ``q-polynomials in random matrix theory and the physics of multifractality'' ABSTRACT OF TALK: A wide variety of quantum systems (like complex nuclei, atoms and molecules, small disordered metals as well as quantum systems whose classical counterparts are chaotic) share some generic statistical properties of energy levels. These properties can be understood most naturally in terms of the stochastic and symmetry properties of the Gaussian Random Matrix Ensembles (RMEs). In this talk I will briefly review how the well known universal (zero parameter) limits of the Gaussian RMEs follow from certain double scaling limits of classical orthogonal polynomials. I will then discuss a new class of RMEs based on the q-orthogonal polynomials which describes the generic statistical properties of quantum systems in the `critical' regime when the system undergoes a phase transition from the chaotic to an integrable state. As an example, I will consider the metal to insulator transition in disordered electronic systems, where this new class of RMEs describe the expected `multifractal' wavefunctions associated with the critical regime. ===========================================================