Detection of relic gravitational waves in thermal case by using Adv.LIGO data of GW150914

The thermal spectrum of relic gravitational waves enhances the usual spectrum. Our analysis shows that there exist some chances for detection of the thermal spectrum in addition to the usual spectrum by comparison with sensitivity of Adv.LIGO of GW150914 and detector based on the maser light. The behavior of the inflation and reheating stages are often known as power law expansion like \(S(\eta )\propto \eta ^{1+\beta }\), \(S(\eta )\propto \eta ^{1+\beta _s}\), respectively, with constraints \(1+\beta <0, 1+\beta _{s}>0\). The \(\beta \) and \(\beta _s\) have an unique effect on the shape of the spectrum. We find some values of the \(\beta \) and \(\beta _s\) by considering the mentioned comparison. As obtained, the results give us more information as regards the evolution of inflation and reheating stages.