VACUUM STRESS-ENERGY TENSOR OF NONCONFORMAL SCALAR FIELD IN QUASI-EUCLIDEAN GRAVITATIONAL BACKGROUND

The vacuum expectation value of the stress-energy tensor of a quantize d scalar field with arbitrary curvature coupling in quasi-Euclidean ba ckground is calculated. The early time approximation for nonconformal fields is introduced. This approximation makes it possible to represen t the matrix elements of the stress-energy tensor as explicit function als of the scale factor. In the case of scale factors depending on tim e by the degree law the energy density is calculated explicitly. It is shown that the new contributions due to nonconformal curvature coupli ng significantly dominate the previously known conformal contributions .