Comparison between formulae for the counting functions of the heights t(n)
of the Riemann zeros and of semiclassical quantum. eigenvalues E-n suggests
that the t(n) are eigenvalues of an (unknown) hermitean operator H, obtain
ed by quantizing a, classical dynamical system with hamiltonian H-cl. Many
features of H-cl are provided by the analogy; for example, the "Riemann dyn
amics" should be chaotic and have periodic orbits whose periods are multipl
es of logarithms of prime numbers. Statistics of the t(n) have a similar st
ructure to those of the semiclassical E-n; in particular, they display rand
om-matrix universality at short range, and nonuniversal behaviour over long
er ranges. Very refined features of the statistics of the t(n) can be compu
ted accurately from formulae with quantum analogues. The Riemann-Siegel for
mula for the zeta function is described in detail. Its interpretation as a
relation between long and short periodic orbits gives further insights into
the quantum spectral fluctuations. We speculate that the Riemann dynamics
is related to the trajectories generated by the classical hamiltonian H-cl
= XP.