Measurement of Parity Violation in the Early Universe using Gravitational-wave Detectors
Cosmology and Nongalactic Astrophysics2015-06-12v1General Relativity and Quantum CosmologyHigh Energy Physics - PhenomenologyHigh Energy Physics - Theory
A stochastic gravitational-wave background (SGWB) is expected to arise from the superposition of many independent and unresolved gravitational-wave signals, of either cosmological or astrophysical origin. Some cosmological models (characterized, for instance, by a pseudo-scalar inflaton, or by some modification of gravity) break parity, leading to a polarized SGWB. We present a new technique to measure this parity violation, which we then apply to the recent results from LIGO to produce the first upper limit on parity violation in the SGWB, assuming a generic power-law SGWB spectrum across the LIGO sensitive frequency region. We also estimate sensitivity to parity violation of the future generations of gravitational-wave detectors, both for a power-law spectrum and for a model of axion inflation. This technique offers a new way of differentiating between the cosmological and astrophysical sources of the isotropic SGWB, as astrophysical sources are not expected to produce a polarized SGWB.
@article{arxiv.1212.4165,
title = {Measurement of Parity Violation in the Early Universe using Gravitational-wave Detectors},
author = {S. G. Crowder and R. Namba and V. Mandic and S. Mukohyama and M. Peloso},
journal= {arXiv preprint arXiv:1212.4165},
year = {2015}
}