An exact analytic spectrum of relic gravitational waves in an accelerating universe

Zhang, Yang; Er, Xinzhong; Xia, Tianyang; Zhao, Wen; Miao, H.

doi:10.1088/0264-9381/23/11/007

Cited by 57 publications

(64 citation statements)

References 41 publications

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“…For the RGWs outside the barrier the corresponding amplitude decreases as h k ∝ 1/S(η) while for the waves inside the barrier, h k = C k simply is a constant. Therefore these results can be used to obtain the spectrum for the present stage of universe [23,32]. The history of the expansion of the universe can be written as follows.…”

Section: Appendix Amentioning

confidence: 99%

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

Ghayour

Khodagholizadeh

2017

Eur. Phys. J. C

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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(η) ∝ η 1+β , S(η) ∝ η 1+β s , respectively, with constraints 1+β < 0, 1+β s > 0. The β and β s have an unique effect on the shape of the spectrum. We find some values of the β and β s by considering the mentioned comparison. As obtained results give us more information about the evolution of inflation and reheating stages.

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Section: Appendix Amentioning

confidence: 99%

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

Ghayour

Khodagholizadeh

2017

Eur. Phys. J. C

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“…By its nature, RGWs constitute a stochastic background, and the mean value of the field h ij is zero at every instance of time and at every spatial point: 0|h ij (x, τ )|0 = 0. But the variance is not zero [25,27,28], Figure 6: The spectrum of RGWs for the cosmological model with the tensor-scalar ratio r = 0.22, the dark energy Ω Λ = 0.75, and the inflation parameter β = −1.9. The spectrum in GHz band depends sensitively on the reheating parameter β s [29].…”

Section: Detecting Rgwsmentioning

confidence: 99%

“…Thus it can serve as the main target of detection using the maser beam. We shall estimate qualitatively the sensitivity of detection of a sample detector, and make a comparison with the known analytic spectrum of RGWs [27,28,29], which has not been made before. The organization of the paper is as follows.…”

Section: Introductionmentioning

confidence: 99%

Using a polarized maser to detect high-frequency relic gravitational waves

Tong

Zhang

2008

Phys. Rev. D

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A GHz maser beam with Gaussian-type distribution passing through a homogenous static magnetic field can be used to detect gravitational waves (GWs) with the same frequency. The presence of GWs will perturb the electromagnetic (EM) fields, giving rise to perturbed photon fluxes (PPFs). After being reflected by a fractal membrane, the perturbed photons suffer little decay and can be measured by a microwave receiver. This idea has been explored to certain extent as a method for very high frequency gravitational waves. In this paper, we examine and develop this method more extensively, and confront the possible detection with the predicted signal of relic gravitational waves (RGWs). A maser beam with high linear polarization is used to reduce the background photon fluxes (BPFs) in the detecting direction as the main noise. As a key factor of applicability of this method, we give a preliminary estimation of the sensitivity of a sample detector limited by thermal noise using currently common technology. The minimal detectable amplitude of GWs is found to be h min ∼ 10 −30 . Comparing with the known spectrum of the RGWs in the accelerating universe for β = −1.9, there is still roughly a gap of 4 ∼ 5 orders. However, possible improvements on the detector can further narrow down the gap and make it a feasible method to detect high frequency RGWs.

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“…From the consideration of physics of the Universe, we take the following specifications [30] − [32]:…”

Section: Rgw In the Accelerating Universementioning

confidence: 99%

“…[30] − [32] However, the resulting spectrum will plotted for illustration. Taking the ratio r = 0.37 and γ = 1.05,…”

Section: Rgw In the Accelerating Universementioning

confidence: 99%

Relic Gravitational Waves and CMB Polarization in the Accelerating Universe

Zhang

Zhao

Xia

et al. 2008

Int. J. Mod. Phys. D

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In this paper we briefly present our works on the relic gravitational waves (RGW) and the CMB polarization in the accelerating universe. The spectrum of RGW has been obtained, showing the influence of the dark energy. Compared with those from non-accelerating models, the shape of the spectrum is approximately similar, nevertheless, the amplitude of RGW now acquires a suppressing factor of the ratio of matter over dark energy ∝ Ω m /Ω Λ ∼ 0.4 over almost the whole range of frequencies. The RGW spectrum is then used as the source to calculate the spectra of CMB polarization. By a two half Gaussian function as an approximation to the visibility function during the photon decoupling, both the "electric" and "magnetic" spectra have been analytically derived, which are quite close to the numerical ones. Several physical elements that affect the spectra have been examined, such as the decoupling process, the inflation, the dark energy, the baryons, etc.

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An exact analytic spectrum of relic gravitational waves in an accelerating universe

Cited by 57 publications

References 41 publications

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

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

Using a polarized maser to detect high-frequency relic gravitational waves

Relic Gravitational Waves and CMB Polarization in the Accelerating Universe

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