Cross-correlating pulsar timing and polarimetry isolates the circular polarization of isotropic stochastic GW backgrounds and shares the Hellings-Downs angular pattern.
Circular Polarization of Primordial Gravitational Waves in String-inspired Inflationary Cosmology
8 Pith papers cite this work. Polarity classification is still indexing.
abstract
We study a mechanism to produce the circular polarization of primordial gravitational waves. The circular polarization is generated during the super-inflation driven by the Gauss-Bonnet term in the string-inspired cosmology. The instability in the tensor mode caused by the Gauss-Bonnet term and the parity violation due to the gravitational Chern-Simons term are the essential ingredients of the mechanism. We also discuss detectability of the produced circular polarization of gravitational waves. It turns out that the simple model of single-field inflation contradicts CMB observations. To circumvent this difficulty, we propose a two-field inflation model. In this two-field model, the circular polarization of gravitational waves is created in the frequency range designed by the Big-Bang Observer (BBO) or the deci-hertz gravitational-wave observatory (DECIGO).
citation-role summary
citation-polarity summary
verdicts
UNVERDICTED 8roles
background 2polarities
background 2representative citing papers
An effective constrained scalar-Gauss-Bonnet inflation model yields n_s ≃ 0.958 and r ≃ 2.7×10^{-4} while the exact theory has no propagating scalar degree of freedom.
Fuzzy dark matter induces frequency-dependent amplitude birefringence in gravitational waves with periodic time modulation set by the scalar mass, but no velocity birefringence.
A transient parity-violating phase during inflation generates a robust blue-tilted (n_T ≃ 2) primordial gravitational wave spectrum at small scales with nearly maximal helicity coherence and linear polarization, offering a cosmological template for PTA data distinct from astrophysical sources.
Dimension-six operators |Φ|²R² and |Φ|⁴R in R²-Higgs inflation accommodate enhanced n_s from CMB+BAO data and enable rapid preheating via Goldstone modes.
Quadratic f(Q) gravity adds an H^4 term to the Friedmann equation and introduces a time-dependent G_eff that suppresses linear growth and halo abundance, offering a modified-gravity route to easing the S8 tension.
Four Einstein-Gauss-Bonnet inflationary models are reconstructed from a chosen tensor-to-scalar ratio and shown to satisfy ACT and GW170817 constraints including scalar perturbation amplitude.
Einstein-Gauss-Bonnet inflation can yield positive spectral-index running with a viable era under ACT-like hints, while scalar-field and F(R) models largely cannot.
citing papers explorer
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Detecting Parity-Violating Gravitational Wave Backgrounds with Pulsar Polarization Arrays
Cross-correlating pulsar timing and polarimetry isolates the circular polarization of isotropic stochastic GW backgrounds and shares the Hellings-Downs angular pattern.
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Effective Constrained Scalar--Gauss--Bonnet Inflation Motivated by $f(R,\mathcal{G})$ Gravity
An effective constrained scalar-Gauss-Bonnet inflation model yields n_s ≃ 0.958 and r ≃ 2.7×10^{-4} while the exact theory has no propagating scalar degree of freedom.
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Gravitational Wave Birefringence from Fuzzy Dark Matter
Fuzzy dark matter induces frequency-dependent amplitude birefringence in gravitational waves with periodic time modulation set by the scalar mass, but no velocity birefringence.
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Transient Parity Violation during Inflation: Implications for PTA Gravitational Waves
A transient parity-violating phase during inflation generates a robust blue-tilted (n_T ≃ 2) primordial gravitational wave spectrum at small scales with nearly maximal helicity coherence and linear polarization, offering a cosmological template for PTA data distinct from astrophysical sources.
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Nonminimal couplings and preheating effects in $R^2$-Higgs inflation after ACT and SPT
Dimension-six operators |Φ|²R² and |Φ|⁴R in R²-Higgs inflation accommodate enhanced n_s from CMB+BAO data and enable rapid preheating via Goldstone modes.
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Late-Time Cosmology and Structure Formation in Quadratic $f(Q)$ Gravity
Quadratic f(Q) gravity adds an H^4 term to the Friedmann equation and introduces a time-dependent G_eff that suppresses linear growth and halo abundance, offering a modified-gravity route to easing the S8 tension.
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Reconstructing ACT-compatible and GW170817-compatible Einstein-Gauss-Bonnet Inflation from the Observational Indices
Four Einstein-Gauss-Bonnet inflationary models are reconstructed from a chosen tensor-to-scalar ratio and shown to satisfy ACT and GW170817 constraints including scalar perturbation amplitude.
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ACT Data and Positive Running of the Spectral Index for Scalar Theory and Modified Gravity
Einstein-Gauss-Bonnet inflation can yield positive spectral-index running with a viable era under ACT-like hints, while scalar-field and F(R) models largely cannot.