2014/10/27 by Jiewen Chen, Yang Zhang, Chen, Jie-Wen +5
Earth and Planetary Sciences · Physics and Astronomy · #Cosmology and Gravitation Theories #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #Geophysics and Gravity Measurements #High Energy Physics - Theory (hep-th) #Pulsars and Gravitational Waves Research
paper · pdf · doi:10.48550/arxiv.1410.7151
openalex publication_date 2014/10/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The relic gravitational wave (RGW) generated during the inflation depends on the initial condition via the amplitude, the spectral index nt and the running index αt. CMB observations so far have only constrained the tensor-scalar ratio r, but not nt nor αt. Complementary to this, the ground-based interferometric detectors working at ∼ 102Hz are able to constrain the spectral indices that influence the spectrum sensitively at high frequencies. In this work we give a proper normalization of the analytical spectrum at the low frequency end, yielding a modification by a factor of ∼ 1/50 to the previous treatment. We calculate the signal-noise ratios (SNR) for various (nt,αt) at fixed r=0.2 by S6 of LIGO H-L, and obtain the observational upper limit on the running index αt<0.02093 (i.e, at a detection rate 95% and a false alarm rate 5%) at the default (nt=0,r=0.2). This is consistent with the constraint on the energy density obtained by LIGO-Virgo Collaboration. Extending to the four correlated detectors currently running, the calculated SNR improves slightly. When extending to the six correlated detectors of the second-generation in design, the calculated SNR is ∼ 103 times over the previous two cases, due to the high sensitivities. RGW can be directly detected by the six 2nd-generation detectors for models with αt>0.01364.