Path-integral Monte Carlo estimator for the dipole polarizability of quantum plasma

We present a path-integral Monte Carlo estimator for calculating the dipole polarizability of interacting Coulomb plasma in the long-wavelength limit, i.e., the optical region. We present comprehensive details and method validation studies for our approach based on both collective and one-particle dipole autocorrelation functions in imaginary time. The simulation of thermal equilibrium in imaginary time has exact Coulomb interactions and Boltzmann quantum statistics. For reference, we use an analytically continued Drude model as the long-wavelength limit of the Lindhard response. Our collective response shows a perfect match to the analytical reference. The one-particle response is used in systematic studies of physical and numerical parameters and to discuss the phenomenological Drude scattering model.