  We study the transport of electrons through a single-mode quantum ring with
electric field induced Rashba spin-orbit interaction that is subjected to an
in-plane magnetic field and weakly coupled to electron reservoirs. Modelling a
ring array by ensemble averaging over a Gaussian distribution of energy level
positions, we predict slow conductance oscillations as a function of the Rashba
interaction and electron density due to spin-orbit interaction-induced beating
of the spacings between the levels crossed by the Fermi energy. Our results
agree with experiments by Nitta c.s., thereby providing an interpretation that
differs from the ordinary Aharonov-Casher effect in a single ring.
