Optical properties of a spherical two-dimensional electron gas in a uniform magnetic field

Using the random phase approximation, we calculate the plasmon frequencies of an electron gas on a two-dimensional spherical surface in the presence of a weak magnetic field. We show that the magnetic field results in a coupling between electronic states with different angular momentum numbers. This coupling results in a blue-shift of the dipolar plasmon resonance with increasing magnetic field. We also investigate how the plasmon energies vary as a function of the number of electrons and radius of the sphere.