Null energy condition violation during inflation and pulsar timing array observations

Abstract

Recently, evidence of stochastic gravitational wave background (SGWB) signals observed by pulsar timing array (PTA) collaborations, has prompted investigations into their origins. We explore the compatibility of a proposed inflationary scenario, incorporating an intermediate null energy condition (NEC)-violating phase, with the PTA observations. The NEC violation potentially amplifies the primordial tensor power spectrum, offering a promising explanation for PTA observations. Numerical analyses, primarily focused on NANOGrav's 15-year results, reveal the model's compatibility with PTA data. Notably, the model predicts a nearly scale-invariant GW spectrum in the mHz frequency range, which sets our scenario apart from other interpretations predicting a red primordial GW spectrum on smaller scales.

arXiv comment14 pages plus one appendix, 4 figures; match published version; reference added; correct a typo in eq.15

References in corpus (61)

• TianQin: a space-borne gravitational wave detector
• Search for an isotropic gravitational-wave background with the Parkes Pulsar Timing Array
• Generalized G-inflation: Inflation with the most general second-order field equations
• Searching for the nano-Hertz stochastic gravitational wave background with the Chinese Pulsar Timing Array Data Release I
• G-inflation: inflation driven by the Galileon field
• Towards a Nonsingular Bouncing Cosmology
• Solid Inflation
• Tensor Perturbations in Inflationary Models as a Probe of Cosmology
• The Null Energy Condition and its violation
• The recent gravitational wave observation by pulsar timing arrays and primordial black holes: the importance of non-gaussianities
• Generic instabilities of non-singular cosmologies in Horndeski theory: a no-go theorem
• The Effective Field Theory of nonsingular cosmology
• Phantom Inflation and Primordial Perturbation Spectrum
• Generalized Galileons: instabilities of bouncing and Genesis cosmologies and modified Genesis
• Fully stable cosmological solutions with a non-singular classical bounce
• Blue-tilted Tensor Spectrum and Thermal History of the Universe
• Stability of Geodesically Complete Cosmologies
• Limits on scalar-induced gravitational waves from the stochastic background by pulsar timing array observations
• A covariant Lagrangian for stable nonsingular bounce
• The Need For Speed: Rapid Refitting Techniques for Bayesian Spectral Characterization of the Gravitational Wave Background Using PTAs
• The Effective Field Theory of nonsingular cosmology: II
• The nanohertz stochastic gravitational wave background from cosmic string loops and the abundant high redshift massive galaxies
• Cosmological bounce and Genesis beyond Horndeski
• Have pulsar timing array methods detected a cosmological phase transition?
• Blue-tilted inflationary tensor spectrum and reheating in the light of NANOGrav results
• Gravitational Waves from SMBH Binaries in Light of the NANOGrav 15-Year Data
• Implications for the Supermassive Black Hole Binaries from the NANOGrav 15-year Data Set
• Inflation with violation of the null energy condition
• Nano-Hertz gravitational waves from collapsing domain walls associated with freeze-in dark matter in light of pulsar timing array observations
• DHOST Bounce
• Scalar induced gravitational waves in light of Pulsar Timing Array data
• Generalised tensor fluctuations and inflation
• Unbraiding the Bounce: Superluminality around the Corner
• QCD-Collapsed Domain Walls: QCD Phase Transition and Gravitational Wave Spectroscopy
• Implications of Nano-Hertz Gravitational Waves on Electroweak Phase Transition in the Singlet Dark Matter Model
• On the possibility of blue tensor spectrum within single field inflation
• Intermittent null energy condition violations during inflation and primordial gravitational waves
• Propagating speed of primordial gravitational waves and inflation
• Blue-tilted Primordial Gravitational Waves from Massive Gravity
• Is there an effect of a nontrivial $c_T$ during inflation?
• NANOGrav signal from axion inflation
• Probing The Early Universe Cosmology With NANOGrav: Possibilities and Limitations
• First post-Newtonian $N$-body problem in Einstein-Cartan theory with the Weyssenhoff fluid: Lagrangian and first integrals
• Emergent Universe and Genesis from the DHOST Cosmology
• Inflation and Alternatives with Blue Tensor Spectra
• Analytical results for binary dynamics at the first post-Newtonian order in Einstein-Cartan theory with the Weyssenhoff fluid
• Towards a reliable calculation of relic radiation from primordial gravitational waves
• Fingerprint of GeV scale right-handed neutrinos on inflationary gravitational waves and PTA data
• Pulsar timing array observations as possible hints for nonsingular cosmology
• Heavy QCD axion model in light of pulsar timing arrays
• Enhancement of gravitational waves at Q-ball decay including non-linear density perturbations
• Generating enhanced parity-violating gravitational waves during inflation with violation of the null energy condition
• Higher-Curvature Corrections and Tensor Modes
• Primordial tensor non-Gaussianities from general single-field inflation with non-Bunch-Davies initial states
• Improved DHOST Genesis
• Generating enhanced primordial GWs during inflation with intermittent violation of NEC and diminishment of GW propagating speed
• Probing the primordial universe with gravitational waves detectors
• Blue running of the primordial tensor spectrum
• Parity-violation in bouncing cosmology
• Perturbative unitarity and NEC violation in genesis cosmology
• Gravitational Wave Background from Phantom Superinflation

Cited by in corpus (18)

• Charting the Nanohertz Gravitational Wave Sky with Pulsar Timing Arrays
• Constraining the impact of standard model phase transitions on primordial black holes
• Constraints on Inflation with Null Energy Condition Violation from Advanced LIGO and Advanced Virgo's First Three Observing Runs
• Toward a test of Gaussianity of a gravitational wave background
• Null energy condition violation and beyond Horndeski physics in light of DESI DR2 data
• Constraining string cosmology with the gravitational-wave background using the NANOGrav 15-year data set
• Interpreting Pulsar Timing Array data of Gravitational Waves with Ekpyrosis-Bouncing Cosmology
• Detecting a Gravitational-Wave Background from Inflation with Null Energy Condition Violation: Prospects for Taiji
• NEC violation in $f(\bar{R},\bar{T})$ gravity in the context of a non-canonical theory via modified Raychaudhuri equation
• Parity-violating primordial gravitational waves from null energy condition violation
• Climbing over the potential barrier during inflation via null energy condition violation
• Thermodynamics of a Non-canonical $f(\bar{R},\bar{T})$ gravity
• Gravitational waves in a cyclic Universe: resilience through cycles and vacuum state
• Multimodality in the Search for New Physics in Pulsar Timing Data and the Case of Kination-amplified Gravitational-wave Background from Inflation
• Implications of pulsar timing arrays for Gauss-Bonnet Inflation
• SageNet: Fast Neural Network Emulation of the Stiff-amplified Gravitational Waves from Inflation
• Gravitational Waves from Primordial Black Holes formed by Null Energy Condition Violation during Inflation
• Testing No slip model with pulsar timing arrays: NANOGrav and IPTA