Relic gravitational waves and their detection

Abstract

As the strong evidence for inflation, the relic gravitational waves (RGW) have been extensively studied. Although, it has not been detected, yet some constraints have been achieved by the observations. Future experiments for the RGW detection are mainly two kinds: the CMB experiments and the laser interferometers. In this paper, we study these current constraints and the detective abilities of future experiments. We calculate the strength of RGW ${\Omega }_g(k)$ in two methods: the analytic method and the numerical method by solving the inflationary flow equations. By the first method we obtain a bound ${\Omega }_g<3.89\times 10^{-16}$ at $\nu =0.1$Hz, where we have used the current constraints on the scalar spectral index, the tensor-scalar ratio, furthermore, we have taken into account of the redshift-suppression effect, the accelerating expansion effect, the neutrino damping effect on the RGW. But the analytic expression of ${\Omega }_g(k)$ depends on the specific inflationary models and not well applies for the waves with very high frequencies. The numerical method is more precise for the waves with high frequencies and applies to any single-field inflationary model. It gives a bound ${\Omega }_g<8.62\times 10^{-14}$, which is independent of the inflationary parameters, and applies to any single-field slow-roll inflationary model. After considering the current constraints on the inflationary parameters, this bound becomes ${\Omega }_g<2\times 10^{-17}$ (see text).

17 pages including 3 figures. Only style is revised

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Cited by in corpus (10)

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• Detecting relic gravitational waves in the CMB: Optimal parameters and their constraints
• WMAP-normalized Inflationary Model Predictions and the Search for Primordial Gravitational Waves with Direct Detection Experiments
• $CPT$ Violating Electrodynamics and Chern-Simons Modified Gravity
• Modifications by QCD transition and $e^{+}{e}^{-}$ annihilation on analytic spectrum of relic gravitational waves in accelerating universe
• Detecting relic gravitational waves in the CMB: Comparison of different methods
• Detecting Relic Gravitational Waves in the CMB: Comparison of Planck and Ground-based Experiments
• Relic Gravitational Waves And CMB Polarization In The Accelerating Universe