On the diagonalization of the discrete Fourier transform

The discrete Fourier transform (DFT) is an important operator which acts on the Hilbert space of complex valued functions on the ring Z/NZ. In the case where N=p is an odd prime number, we exhibit a canonical basis of eigenvectors for the DFT. The transition matrix from the standard basis to the canonical basis defines a novel transform which we call the discrete oscillator transform (DOT for short). Finally, we describe a fast algorithm for computing the discrete oscillator transform in certain cases.Comment: Accepted for publication in the journal "Applied and Computational Harmonic Analysis": Appl. Comput. Harmon. Anal. (2009), doi:10.1016/j.acha.2008.11.003. Key words: Discrete Fourier Transform, Weil Representation, Canonical Eigenvectors, Oscillator Transform, Fast Oscillator Transfor

Proof of the Kurlberg-Rudnick Rate Conjecture

In this paper we present a proof of the {\it Hecke quantum unique ergodicity rate conjecture} for the Berry-Hannay model. A model of quantum mechanics on the 2-dimensional torus. This conjecture was stated in Z. Rudnick's lectures at MSRI, Berkeley 1999 and ECM, Barcelona 2000.Comment: In this version we add a proof that the character sheaf of the Heisenberg-Weil representation is perverse, geometrically irreducible of pure weight 0. Moreover, we supply invariant formulas for the character sheaf on an appropriate open set, and we give also another alternative proof for the rate conjecture that uses our invariant formula