EFFECTS OF CURVATURE COUPLINGS FOR QUANTUM-FIELDS ON COSMIC-STRING SPACE-TIMES

The effect of R curvature coupling terms in the equation of motion of a massless scalar field are considered on a cosmic-string background. Realistic two- and four-dimensional models of a string, where the space-time curvature is spread over a region of nonzero size r0, are constructed. In two and four dimensions, the nonzero term modifies the behavior within a region centered about the string, whose radius is proportional to r0; however, the constant of proportionality may be exponentially large. For the standard idealized string (a conical space-time) which has no intrinsic length scale, the effects of nonzero do not appear. © 1990 The American Physical Society.