Abstract:
We present a range of fluctuation and large deviations results for the logarithm of the characteristic polynomial Z of a random N×N unitary matrix, as N→∞. First we show that , evaluated at a finite set of distinct points, is asymptotically a collection of i.i.d. complex normal random variables. This leads to a refinement of a recent central limit theorem due to Keating and Snaith, and also explains the covariance structure of the eigenvalue counting function. Next we obtain a central limit theorem for ln Z in a Sobolev space of generalised functions on the unit circle. In this limiting regime, lower-order terms which reflect the global covariance structure are no longer negligible and feature in the covariance structure of the limiting Gaussian measure. Large deviations results for ln Z/A, evaluated at a finite set of distinct points, can be obtained for . For higher-order scalings we obtain large deviations results for ln Z/A evaluated at a single point. There is a phase transition at A= ln N (which only applies to negative deviations of the real part) reflecting a switch from global to local conspiracy.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Received: 27 June 2000 / Accepted: 30 January 2001
Rights and permissions
About this article
Cite this article
Hughes, C., Keating, J. & O'Connell, N. On the Characteristic Polynomial¶ of a Random Unitary Matrix. Commun. Math. Phys. 220, 429–451 (2001). https://doi.org/10.1007/s002200100453
Issue Date:
DOI: https://doi.org/10.1007/s002200100453