Title

Quantum Equivalence Principle Violations in Scalar-Tensor Theories

Author(s)/Creator(s)

Christian Armendariz-Picon, Department of Physics, Syracuse University, Syracuse, NYFollow
Riccardo Penco, Syracuse University

Document Type

Article

Date

8-30-2011

Language

English

Disciplines

Physics

Description/Abstract

We study the equivalence principle and its violations by quantum effects in scalar-tensor theories that admit a conformal frame in which matter only couples to the spacetime metric. These theories possess Ward identities that guarantee the validity of the weak equivalence principle to all orders in the matter coupling constants. These Ward identities originate from a broken Weyl symmetry under which the scalar field transforms by a shift, and from the symmetry required to couple a massless spin two particle to matter (diffeomorphism invariance). But the same identities also predict violations of the weak equivalence principle relatively suppressed by at least two powers of the gravitational couplings, and imply that quantum corrections do not preserve the structure of the action of these theories. We illustrate our analysis with a set of specific examples for spin zero and spin half matter fields that show why matter couplings do respect the equivalence principle, and how the couplings to the gravitational scalar lead to the weak equivalence principle violations predicted by the Ward identities.

Additional Information

46 pages, 9 figures, uses FeynMP More information at http://arxiv.org/abs/1108.6028

Recommended Citation

Armendariz-Picon, Christian and Penco, Riccardo, "Quantum Equivalence Principle Violations in Scalar-Tensor Theories" (2011). Physics - All Scholarship. 210.
https://surface.syr.edu/phy/210

Source

Harvested from Arxiv.org