Conductivity of a Degenerate Electron Gas

The high-frequency, wave-vector-dependent conductivity of a degenerate electron gas near equilibrium is calculated by taking into account the zero-, the first-, and two of the second-order diagrams in the effective interparticle interaction. Approximate formulas are derived for the case when the frequency $\ensuremath{\omega}$ of the electromagnetic wave is high and its wave vector $k$ is small, i.e., $\ensuremath{\omega}\ensuremath{\gg}\frac{k{p}_{\mathrm{F}}}{m}$, where ${p}_{\mathrm{F}}$ is the Fermi momentum of the electron gas.