CLASSICAL AND QUANTUM GRAVITY, cilt.14, sa.12, ss.3215-3224, 1997 (SCI-Expanded)
We study the interaction of a massless quantized spinor field with the gravitational field of N parallel static cosmic strings by using a perturbative approach. We show that the presence of more than one cosmic string gives rise to an additional contribution to the energy density of vacuum fluctuations, thereby leading to a vacuum force of attraction between two parallel cosmic strings.