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arXiv · 2012.03498

Cross-correlations as a Diagnostic Tool for Primordial Gravitational Waves

Ameek Malhotra·Ema Dimastrogiovanni·Matteo Fasiello·Maresuke Shiraishi
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Abstract

We explore and corroborate, by working out explicit examples, the effectiveness of cross-correlating stochastic gravitational wave background anisotropies with CMB temperature fluctuations as a way to establish the primordial nature of a given gravitational wave signal. We consider the case of gravitational wave anisotropies induced by scalar-tensor-tensor primordial non-Gaussianity. Our analysis spans anisotropies exhibiting different angular behaviours, including a quadrupolar dependence. We calculate the expected uncertainty on the non-linearity parameter $F_{\rm NL}$ obtained as a result of cross-correlation measurements for several proposed experiments such as the ground-based Einstein Telescope, Cosmic Explorer, and the space-based Big-Bang Observer. As a benchmark for future survey planning, we also calculate the theoretical, cosmic-variance-limited, error on the non-linearity parameter.

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Ameek Malhotra, Ema Dimastrogiovanni, Matteo Fasiello, Maresuke Shiraishi. 2020-12-07. Cross-correlations as a Diagnostic Tool for Primordial Gravitational Waves. https://doi.org/10.1088/1475-7516%2F2021%2F03%2F088

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