Berezin transform on the quantum unit ball

: We introduce and study, in the framework of a theory of quantum Cartan domains, a q -analogue of the Berezin transform on the unit ball. We construct q -analogues of weighted Bergman spaces, Toeplitz operators and covariant symbol calculus. In studying the analytical properties of the Berezin transform we introduce also the q -analogue of the SU ( n, 1)-invariant Laplace operator (the Laplace-Beltrami operator) and present related results on harmonic analysis on the quantum ball.. These are applied to obtain an analogue of one result by A. Unterberger and H. Upmeier. An explicit asymptotic formula expressing the q -Berezin transform via the q -Laplace-Beltrami operator is also derived. At the end of the paper, we give an application of our results to basic hypergeometric q -orthogonal polynomials.