The \Phi^4 quantum field in a scale invariant random metric
  We discuss a D-dimensional Euclidean scalar field interacting with a scale invariant quantized metric. We assume that the metric depends on d-dimensional coordinates where d<D. We show that the interacting quantum fields have more regular short distance behaviour than the free fields. A model of a Gaussian metric is discussed in detail. In particular, in the \Phi^4 theory in four dimensions we obtain explicit lower and upper bounds for each term of the perturbation series. It turns out that there is no coupling constant renormalization in the \Phi^4 model in four dimensions. We show that in a particular range of the scale dimension there are models in D=4 without any divergencies. 
Z. Haba (University of Wroclaw)