Calibrates a one-parameter semi-analytic damping model for oscillatory primordial power spectrum features using N-body simulations and validates sub-percent accuracy via GPR emulation when modulation frequency is high enough.
Features and New Physical Scales in Primordial Observables: Theory and Observation
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abstract
All cosmological observations to date are consistent with adiabatic, Gaussian and nearly scale invariant initial conditions. These findings provide strong evidence for a particular symmetry breaking pattern in the very early universe (with a close to vanishing order parameter, $\epsilon$), widely accepted as conforming to the predictions of the simplest realizations of the inflationary paradigm. However, given that our observations are only privy to perturbations, in inferring something about the background that gave rise to them, it should be clear that many different underlying constructions project onto the same set of cosmological observables. Features in the primordial correlation functions, if present, would offer a unique and discriminating window onto the parent theory in which the mechanism that generated the initial conditions is embedded. In certain contexts, simple linear response theory allows us to infer new characteristic scales from the presence of features that can break the aforementioned degeneracies among different background models, and in some cases can even offer a limited spectroscopy of the heavier degrees of freedom that couple to the inflaton. In this review, we offer a pedagogical survey of the diverse, theoretically well grounded mechanisms which can imprint features into primordial correlation functions in addition to reviewing the techniques one can employ to probe observations. These observations include cosmic microwave background anisotropies and spectral distortions as well as the matter two and three point functions as inferred from large-scale structure and potentially, 21 cm surveys.
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BOSS + eBOSS galaxy clustering favors a featureless, quasi-scale-invariant primordial spectrum, with a reconstructed spectral index n_s = 0.976 ± 0.021.
A shear-free locally FLRW lattice framework for single-field inflation captures spatially varying expansion, curvature corrections, and nonlinear δN observables at a fraction of the cost of full numerical relativity.
Joint power spectrum and bispectrum analysis from future HI intensity mapping surveys improves constraints on primordial feature amplitudes by 30-40% and achieves percent-level precision on oscillation frequencies when combined with CMB measurements.
Genetic algorithm reconstructs single-field inflationary models with features in the scalar power spectrum that fit Planck 2018 CMB data better by Δχ² ≲ -10 and suggest alternative background parameters.
Systematic re-analysis of Planck PR3 and PR4 CMB datasets finds local fit improvements of up to Δχ² ≈ -15 for certain oscillatory templates but no global significance above 2.6σ after look-elsewhere correction and Bayesian penalties.
Updated SKAO-AA4 forecasts show multi-tracer HI+galaxy analyses can reach σ(f_local_NL)≲1 and improve αs bounds by tens of percent when combined with future CMB, while foregrounds and GR light-cone effects remain the main systematics.
A review chapter summarizing theoretical 21-cm signatures from Cosmic Dawn and Reionization and their detectability with SKA-Low.
A review that unifies analytical expressions for scalar-induced gravitational waves and emphasizes calculations for non-radiation-dominated cosmologies.
citing papers explorer
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(The) Wiggles going non-linear
Calibrates a one-parameter semi-analytic damping model for oscillatory primordial power spectrum features using N-body simulations and validates sub-percent accuracy via GPR emulation when modulation frequency is high enough.
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Primordial power spectrum reconstructions from BOSS + eBOSS
BOSS + eBOSS galaxy clustering favors a featureless, quasi-scale-invariant primordial spectrum, with a reconstructed spectral index n_s = 0.976 ± 0.021.
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Nonlinear Lattice Framework for Inflation: Bridging stochastic inflation and the $\delta{N}$ formalism
A shear-free locally FLRW lattice framework for single-field inflation captures spatially varying expansion, curvature corrections, and nonlinear δN observables at a fraction of the cost of full numerical relativity.
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Searching for primordial features with radio surveys: synergy between the power spectrum and bispectrum
Joint power spectrum and bispectrum analysis from future HI intensity mapping surveys improves constraints on primordial feature amplitudes by 30-40% and achieves percent-level precision on oscillation frequencies when combined with CMB measurements.
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Reconstructing inflationary features on large scales using genetic algorithm
Genetic algorithm reconstructs single-field inflationary models with features in the scalar power spectrum that fit Planck 2018 CMB data better by Δχ² ≲ -10 and suggest alternative background parameters.
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Signals from the early Universe: a comprehensive search for primordial features in Planck CMB datasets
Systematic re-analysis of Planck PR3 and PR4 CMB datasets finds local fit improvements of up to Δχ² ≈ -15 for certain oscillatory templates but no global significance above 2.6σ after look-elsewhere correction and Bayesian penalties.
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Beyond {\Lambda}CDM with the SKA Observatory -- II: Unveiling the Secrets of the Early Universe
Updated SKAO-AA4 forecasts show multi-tracer HI+galaxy analyses can reach σ(f_local_NL)≲1 and improve αs bounds by tens of percent when combined with future CMB, while foregrounds and GR light-cone effects remain the main systematics.
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High-Redshift Signatures from the Cosmic Dawn and the Epoch of Reionization
A review chapter summarizing theoretical 21-cm signatures from Cosmic Dawn and Reionization and their detectability with SKA-Low.
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Scalar induced gravitational waves review
A review that unifies analytical expressions for scalar-induced gravitational waves and emphasizes calculations for non-radiation-dominated cosmologies.