Pulsar timing array observations as possible hints for nonsingular cosmology

Abstract

Recent pulsar timing array (PTA) experiments have reported strong evidence of the stochastic gravitational wave background (SGWB). If interpreted as primordial gravitational waves (GWs), the signal favors a strongly blue-tilted spectrum. Consequently, the nonsingular cosmology, which is able to predict a strongly blue-tilted GW spectrum with $n_T\simeq 2$ on certain scales, offers a potential explanation for the observed SGWB signal. In this paper, we present a Genesis-inflation model capable of explaining the SGWB signal observed by the PTA collaborations while also overcoming the initial singularity problem associated with the inflationary cosmology. Furthermore, our model predicts distinctive features in the SGWB spectrum, which might be examined by forthcoming space-based gravitational wave experiments.

20 pages, 8 figures; references added, published in EPJC

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Cited by in corpus (21)

• Implications of Nano-Hertz Gravitational Waves on Electroweak Phase Transition in the Singlet Dark Matter Model
• Simultaneously probing the sound speed and equation of state of the early Universe with pulsar timing arrays
• Exploring the NANOGrav Signal and Planet-mass Primordial Black Holes through Higgs Inflation
• Probing the speed of scalar-induced gravitational waves with pulsar timing arrays
• Realisation of the ultra-slow roll phase in Galileon inflation and PBH overproduction
• Enhancement of gravitational waves at Q-ball decay including non-linear density perturbations
• Null energy condition violation during inflation and pulsar timing array observations
• Obviating PBH overproduction for SIGWs generated by Pulsar Timing Arrays in loop corrected EFT of bounce
• Can we distinguish the adiabatic fluctuations and isocurvature fluctuations with pulsar timing arrays?
• Charting the Nanohertz Gravitational Wave Sky with Pulsar Timing Arrays
• Regularized-Renormalized-Resummed loop corrected power spectrum of non-singular bounce with Primordial Black Hole formation
• Untangling PBH overproduction in $w$-SIGWs generated by Pulsar Timing Arrays for MST-EFT of single field inflation
• Toward a test of Gaussianity of a gravitational wave background
• Negative non-Gaussianity as a salvager for PBHs with PTAs in bounce
• Interpreting Pulsar Timing Array data of Gravitational Waves with Ekpyrosis-Bouncing Cosmology
• Interplay between the muon $g-2$ anomaly and the PTA nHZ gravitational waves from domain walls in next-to minimal supersymmetric standard model
• Parity-violating primordial gravitational waves from null energy condition violation
• Climbing over the potential barrier during inflation via null energy condition violation
• Implications of pulsar timing arrays for Gauss-Bonnet Inflation
• Search for the non-linearities of gravitational wave background in NANOGrav 15-year data set
• Primordial Black Holes from Spatially Varying Cosmological Constant Induced by Field Fluctuations in Extra Dimensions