Wormholes with scalar fields

Wormholes solutions are discussed in a theory with antisymmetric 3-rank tensor field H mu nu rho (axion) coupled to scalar fields. The authors also consider a generalised gravity theory, which action is given by S= integral d 4 x square root -g(F( phi ,R)- 1 / 2 h( phi )( Del phi ) 2 -g 2 H mu nu rho 2 ), with F( phi ,R) and h( phi ) being arbitrary functions of a scalar phi and a scalar curvature R. Since it is conformally equivalent to the Einstein-Hilbert system with H mu nu rho coupled to a scalar field, the authors can apply the above discussion to such a theory. Most models (R 2 model, Jordan-Brans-Dicke theory, Zee's induced gravity model and the Einstein theory with non-minimal coupling) contain wormhole solutions. Although a wormhole solution cannot occur in the four-dimensional effective theory from a superstring model (Giddings and Strominger (1988)), if the effective theory has a scalar field (not dilaton) coupled non-minimally, a wormhole solution becomes possible.