Macroscopic backreaction of the trace anomaly on classical vacuum backgrounds

We study the backreaction of quantum fields in the Boulware vacuum state on the Schwarzschild geometry, using the Riegert–Mottola–Vaulin renormalized stress-energy tensor derived from the conformal anomaly. An order-reduction procedure is applied to the first order, paying special attention to the conservation of the resulting stress-energy tensor. The results obtained in these different situations are compared between them, and also to recent works in the literature using other approximations for the renormalized stress-energy tensor.