Recovering the leading quantum correction to Newton Potential beyond the Trace Anomaly

Abstract

The leading quantum correction to the Newton potential induced by the one-loop vacuum effective action of gravity is of order $1/r^3$. One-loop corrections are also responsible for the trace anomaly. We first show, following our previous work, that the effective action obtained by integrating the trace anomaly cannot reproduce this correction. We then complete the semiclassical Einstein equations with the vacuum-polarization stress tensor in addition to the anomalous stress tensor. The full stress tensor follows from the approximation proposed by Visser for the Schwarzschild spacetime. The stress tensor is taken in the Boulware vacuum and expanded at large distance, where it is conserved and reproduces the trace anomaly. Solving the equations perturbatively in $\hbar$, we find that Visser's approximation generates the $1/r^3$ correction to the Newton potential, linear in the source mass $M$, with the same structure as the one-loop result. Its coefficient is controlled by a single free parameter of Visser's polynomial ansatz, which can be tuned to match the one-loop value. The dependence on the trace-anomaly coefficient appears only at order $1/r^4$.