Michele's wiki/blog

Authors: Stephon Alexander, Nicolas Yunes

Date: Wed, 28 Mar 2007

Abstract: We study Chern-Simons (CS) gravity in the parameterized post-Newtonian (PPN) framework through weak-field solutions of the modified field equations for a perfect fluid source. We discover that CS gravity possesses the same PPN parameters as general relativity, except for the inclusion of a new term, proportional both to the CS coupling parameter and the curl of the PPN vector potentials. This new term encodes the key physical effect of CS gravity in the weak-field limit, leading to a modification of frame dragging and, thus, the Lense-Thirring contribution to gyroscopic precession. We provide a physical interpretation for the new term, as well as an estimate of the size of this effect relative to the general relativistic Lense-Thirring prediction. This correction to frame dragging might be used in experiments, such as Gravity Probe B and lunar ranging, to place bounds on the CS coupling parameter, as well as other intrinsic parameters of string theory.

abs pdf