Electronic excitations of an electron-gas cylinder bundle

We study the dielectric response function of an electron-gas cylinder bundle. The electron-electron interactions among different cylinders are taken into account. The electronic excitations are associated with those of an isolated cylinder. However, a cylinder bundle exhibits the three-dimensional characteristics, but a single cylinder the one-dimensional characteristics. The excitation properties are highly anisotropic. The plasma oscillations perpendicular and parallel to the axial direction quite differs from each other. The ratio between their oscillation frequencies is generally smaller than 1/√2, which depends on the cylinder radius and the effective mass.