Measuring a Parity Violation Signature in the Early Universe via Ground-based Laser Interferometers

TL;DR

This paper proposes using pairs of ground-based laser interferometers to detect parity violation in the early universe by measuring the Stokes parameter V of a gravitational wave background, enabling separate assessment of intensity and asymmetry.

Contribution

It introduces a method utilizing widely separated interferometer pairs to distinguish the parity-violating component of gravitational waves from the overall background.

Findings

Pairs like LIGO-Livingston and LCGT are effective for measuring V.

At least three detectors are needed to separately measure Omega_GW and V.

The approach enhances sensitivity to parity violation signals in gravitational wave data.

Abstract

We show that pairs of widely separated interferometers are advantageous for measuring the Stokes parameter V of a stochastic background of gravitational waves. This parameter characterizes asymmetry of amplitudes of right- and left-handed waves and generation of the asymmetry is closely related to parity violation in the early universe. The advantageous pairs include LIGO(Livingston)-LCGT and AIGO-Virgo that are relatively insensitive to Omega_GW (the simple intensity of the background). Using at least three detectors, information of the intensity Omega_GW and the degree of asymmetry V can be separately measured.