CHRONOLOGY PROTECTION AND QUANTIZED-FIELDS - NONCONFORMAL AND MASSIVESCALAR FIELDS IN MISNER SPACE

In the absence of an adequate theory of quantum gravity, the search fo r a mechanism of ''chronology protection'' is currently focused on the vacuum energy divergence of quantized matter fields at chronology hor izons and its back reaction on the metric via the semiclassical theory of gravity. The divergence of the vacuum energy at the chronology hor izon was first demonstrated by Hiscock and Konkowski for a conformal m assless scalar field in the Misner space. In this paper, we extend thi s earlier work to calculate the vacuum stress-energy tensor of a massi ve nonconformally coupled scalar field in Misner space. We find that t he asymptotic behavior of [T(muvu)] as it diverges at the chronology h orizon is, to leading order, independent of the curvature coupling and mass of the scalar field. Thus the vacuum energy of nonconformal and/ or massive scalar fields diverges with the same strength as the massle ss conformal case. Since one important aspect of gravity is its noncon formal nature, this suggests that quantum gravity may be unable to act as the protector of chronology.