Is the NANOGrav signal a hint of dS decay during inflation?

Abstract

As suggested by the swampland conjectures, de Sitter (dS) space might be highly unstable if it exists at all. During inflation, the short-lived dS states will decay through a cascade of the first-order phase transition (PT). We find that the gravitational waves (GWs) yielded by such a PT will be "reddened" by subsequent dS expansion, which may result in a slightly red-tilt stochastic GWs background at low-frequency band, compatible with the NANOGrav 12.5-yr result.

arXiv comment12 pages,3 figures, published version

References in corpus (30)

• On the Geometry of the String Landscape and the Swampland
• Statistics of Cosmic Microwave Background Polarization
• Cosmological Backgrounds of Gravitational Waves
• A Probe of Primordial Gravity Waves and Vorticity
• Distance and de Sitter Conjectures on the Swampland
• De Sitter Space and the Swampland
• General Properties of the Gravitational Wave Spectrum from Phase Transitions
• Gravitational wave generation from bubble collisions in first-order phase transitions: an analytic approach
• Probing the early universe with inflationary gravitational waves
• Tensor Perturbations in Inflationary Models as a Probe of Cosmology
• Gravitational waves from bubble collisions: analytic derivation
• Is the Hubble tension a hint of AdS phase around recombination?
• Gravitational waves from vacuum first-order phase transitions: from the envelope to the lattice
• Trans-Planckian Censorship and Inflationary Cosmology
• Phantom Inflation and Primordial Perturbation Spectrum
• Gauged Supergravities, de Sitter Space and Cosmology
• Relic gravitational waves and their detection
• Revisiting the envelope approximation: gravitational waves from bubble collisions
• Inflation with violation of the null energy condition
• Trans-Planckian censorship and other swampland bothers addressed in warm inflation
• Propagating speed of primordial gravitational waves and inflation
• Is there an effect of a nontrivial $c_T$ during inflation?
• Trans-Planckian censorship of multistage inflation and dark energy
• Trans-Planckian Censorship Conjecture and Non-thermal post-inflationary history
• Inflating with the QCD Axion
• Preheating and symmetry restoration in collisions of vacuum bubbles
• Echoes of Inflationary First-Order Phase Transitions in the CMB
• Non-Standard Cosmological Models and the trans-Planckian Censorship Conjecture
• Phase-transition sound of inflation at gravitational waves detectors
• Preheating in Bubble Collisions

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• Primordial gravitational waves from NANOGrav: a broken power-law approach
• On the perturbative expansion at high temperature and implications for cosmological phase transitions
• Decoding the phases of early and late time reheating through imprints on primordial gravitational waves
• Blue-tilted inflationary tensor spectrum and reheating in the light of NANOGrav results
• The Detected Stochastic Gravitational Waves and Subsolar-Mass Primordial Black Holes
• The NANOGrav 12.5-year data set: Search for Non-Einsteinian Polarization Modes in theGravitational-Wave Background
• Towards hybrid inflation with $n_s=1$ in light of Hubble tension and primordial gravitational waves
• Intermittent null energy condition violations during inflation and primordial gravitational waves
• NANOGrav Signal from First-Order Confinement/Deconfinement Phase Transition in Different QCD Matters
• Broken blue-tilted inflationary gravitational waves: a joint analysis of NANOGrav 15-year and BICEP/Keck 2018 data
• Implications of the NANOGrav result on primordial gravitational waves in nonstandard cosmologies
• Escape from supercooling with or without bubbles: gravitational wave signatures
• NANOGrav signal and LIGO-Virgo Primordial Black Holes from the Higgs field
• Testing clockwork axion with gravitational waves
• Can the gravitational wave background feel wiggles in spacetime?
• NANOGrav Hints on Planet-Mass Primordial Black Holes
• Pulsar Timing Residual induced by Wideband Ultralight Dark Matter with Spin 0, 1, 2
• Generating enhanced primordial GWs during inflation with intermittent violation of NEC and diminishment of GW propagating speed
• Implications of cosmologically coupled black holes for pulsar timing arrays
• Scalar induced gravitational waves review
• Hitchhiker's Guide to the Swampland: The Cosmologist's Handbook to the string-theoretical Swampland Programme
• Gravitational wave signal from primordial magnetic fields in the Pulsar Timing Array frequency band
• Search for the non-linearities of gravitational wave background in NANOGrav 15-year data set
• Curvature perturbations from vacuum transition during inflation
• Inflationary phase transitions in the early Universe: A Bayesian study with space-based gravitational-wave detectors