Observable signals in a string inspired axion-dilaton background and Randall-Sundrum scenario

TL;DR

This paper investigates how axion and dilaton fields in string theory, especially within a Randall-Sundrum braneworld scenario, can cause observable polarization rotation in distant galactic radio waves, comparing theoretical predictions with cosmological data.

Contribution

It provides a detailed analysis of optical rotation effects caused by axion-dilaton backgrounds and explores the impact of warped extra dimensions on these signals in a string-inspired framework.

Findings

Axion induces wavelength-independent optical rotation larger than dilaton.

Theoretical rotation values are consistent with recent cosmological observations.

Warped extra dimensions influence the magnitude of polarization rotation.

Abstract

Rotation angle of the plane of polarization of the distant galactic radio waves has been estimated in a string inspired axion-dilaton background. It is found that the axion,dual to the field strength of the second rank antisymmetric massless Kalb-Ramond field in the string spectrum, produces a wavelength independent optical rotation which is much larger than that produced by the dilaton. Detection of such rotation has been reported in some recent cosmological experiments. The observed value has been compared with our estimated theoretical value following various cosmological constraints. The effects of warped extra dimensions in a braneworld scenario on such an optical rotation have been investigated.