Frequency-dependent conductance of a tunnel junction

The linear conductance of the a small metallic tunnel junction embedded in an electromagnetic environment of arbitrary impedance is determined in the semiclassical limit. Electron tunneling is treated beyond the orthodox theo ry of Coulomb blockade phenomena by means of a nonperturbative path integra l approach. The frequency dependent conductance is obtained from Kubo's for mula. The theoretical predictions are valid for high temperatures and/or fo r large tunneling conductance and are found to explain recent experimental data. (C) Academie des sciences/Elsevier, Paris.