Vacuum energies and multipole interactions
  In this paper, we present a quantum-field-theoretical description of the interaction between stationary and localized external sources linearly coupled to bosonic fields (specifically, we study models with a scalar and the Maxwell field). We consider external sources that simulate not only point charges but also higher-multipole distributions along D-dimensional branes. Our results complement the ones previously obtained in reference [1]. 
Fabricio Augusto Barone Rangel, Gabriel Flores-Hidalgo
hep-th