The prospects for direct measurements of inflationary gravitational waves by next generation interferometric detectors inferred from the possible detection of B-mode polarization of the cosmic microwave background are studied. We compute the spectra of the gravitational wave background and the signal-to-noise ratios by two interferometric detectors (DECIGO and BBO) for large-field inflationary models in which the tensor-to-scalar ratio is greater than the order of 0.01. If the reheating temperature TRH of chaotic inflation with the quadratic potential is high (TRH>7.9×106 GeV for upgraded DECIGO and TRH>1.8×106 GeV for BBO), it will be possible to reach the sensitivity of the gravitational background in future experiments at 3σ confidence level. The direct detection is also possible for natural inflation with the potential V(φ)=Λ4[1-cos(φ/f)], provided that f>4.2Mpl (upgraded DECIGO) and f>3.6Mpl (BBO) with TRH higher than 108 GeV. The quartic potential V(φ)=λφ4/4 with a nonminimal coupling ξ between the inflaton field φ and the Ricci scalar R gives rise to a detectable level of gravitational waves for |ξ| smaller than the order of 0.01, irrespective of the reheating temperature.
|Physical Review D - Particles, Fields, Gravitation and Cosmology
|Published - 2014 Sept 12
ASJC Scopus subject areas
- Nuclear and High Energy Physics
- Physics and Astronomy (miscellaneous)