Imprint of Scalar Dark Energy on Cosmic Microwave Background Polarization

TL;DR

This paper investigates how scalar dark energy interacting with photons could leave detectable signatures in the CMB polarization, potentially revealing new physics related to dark energy and cosmic parity violation.

Contribution

It introduces the theoretical framework for scalar dark energy's impact on CMB polarization, highlighting potential observable effects like $B$-modes and parity violation.

Findings

Scalar dark energy can induce $B$-mode polarization in the CMB.

Future observations may detect parity violation in temperature-polarization correlation.

Perturbation effects could mimic signals from gravitational lensing or primordial gravitational waves.

Abstract

We study the imprint of a coupling of scalar dark energy to photon on the cosmic microwave background (CMB) polarization. The time-evolving field value as well as the perturbation of the scalar generically induce $B$-mode polarization. Future CMB data will find either a cosmic parity violation in temperature-polarization correlation due to the field value, or perturbation-induced $B$-mode polarization that is almost indistinguishable from that generated by gravitational lensing or primordial gravitational waves.