String Theoretic Bounds on Lorentz-Violating Warped Compactification

TL;DR

This paper explores string theory models with asymmetric warping that violate Lorentz invariance, calculating corrections to particle dispersion relations and setting new limits on gravitational Lorentz violation.

Contribution

It provides a string-theoretic framework for asymmetric warped compactifications and derives bounds on Lorentz violation from dispersion relation corrections.

Findings

Limits on gravitational Lorentz violation are improved.

Stringy corrections to standard model dispersion relations are calculated.

Viability of asymmetric warping for cosmological constant self-tuning is discussed.

Abstract

We consider warped compactifications that solve the 10 dimensional supergravity equations of motion at a point, stabilize the position of a D3-brane world, and admit a warp factor that violates Lorentz invariance along the brane. This gives a string embedding of ``asymmetrically warped'' models which we use to calculate stringy (\alpha') corrections to standard model dispersion relations, paying attention to the maximum speeds for different particles. We find, from the dispersion relations, limits on gravitational Lorentz violation in these models, improving on current limits on the speed of graviton propagation, including those derived from field theoretic loops. We comment on the viability of models that use asymmetric warping for self-tuning of the brane cosmological constant.