Dynamic magnetoconductance fluctuations and oscillations in mesoscopic wires and rings

Using a finite-frequency recursive Green’s-function technique, we calculate the dynamic magnetoconductance fluctuations and oscillations in disordered mesoscopic normal-metal systems, incorporating interparticle Coulomb interactions within a self-consistent potential method. In a disorderd metal wire, we observe ergodic behavior in the dynamic conductance fluctuations. At low ω, the real part of the conductance fluctuations is essentially given by the dc universal conductance fluctuations while the imaginary part increases linearly from zero, but for ω greater than the Thouless energy and temperature, the fluctuations decrease as ${\mathrm{\omega }}^{\mathrm{-}1/2}$. Similar frequency-dependent behavior is found for the Aharonov-Bohm oscillations in a metal ring. However, the Al’tshuler-Aronov-Spivak oscillations, which predominate at high temperatures or in rings with many channels, are strongly suppressed at high frequencies, leading to interesting crossover effects in the ω dependence of the magnetoconductance oscillations.