For infinitely differentiable effective potentials describing the post-inflation transition, the regularized power spectrum of primary gravitational waves exhibits exponential suppression at small scales.
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TASI Lectures on Inflation
Canonical reference. 73% of citing Pith papers cite this work as background.
abstract
In a series of five lectures I review inflationary cosmology. I begin with a description of the initial conditions problems of the Friedmann-Robertson-Walker (FRW) cosmology and then explain how inflation, an early period of accelerated expansion, solves these problems. Next, I describe how inflation transforms microscopic quantum fluctuations into macroscopic seeds for cosmological structure formation. I present in full detail the famous calculation for the primordial spectra of scalar and tensor fluctuations. I then define the inverse problem of extracting information on the inflationary era from observations of cosmic microwave background fluctuations. The current observational evidence for inflation and opportunities for future tests of inflation are discussed. Finally, I review the challenge of relating inflation to fundamental physics by giving an account of inflation in string theory.
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Compactified 5D unparticle theories generate gapped excitations whose exchange in inflationary correlators yields oscillations modulated by anomalous dimensions and possible interference patterns under brane-localized interactions.
Computes inflationary bispectra and trispectra from tree-level unparticle exchanges using Mellin-Barnes methods and symmetry-based differential equations, revealing that full shapes are needed to distinguish unparticles from light particles.
Small 7B reasoning models were fine-tuned on synthetic and curated QFT problems using RL and SFT, yielding performance gains, error analysis, and public release of data and traces.
In an LQC bouncing cosmology, second-order quantum moments yield a Planck-suppressed scale-dependent correction δP_R ∝ (k ℓ_Pl)^6 to the curvature power spectrum together with post-bounce damping from gravitational moments.
The paper develops a descriptive framework in which scientific reward in physics is understood as transformations of the Polydoxon, the structured set of viable theories, with reward scaling by the transformation's scope, centrality, depth, and future leverage.
Fractional cosmology produces emergent inflation as a stable attractor from a non-singular pre-inflationary regime, with the number of e-folds related to the fractional parameter α and a subsequent radiation-dominated era.
No evidence for primordial hotspots in Planck polarization data leads to improved bounds on inflationary particle production couplings for light particles.
The stochastic noise amplitude is modified to (H/2π) * sqrt(1 + ΔP_R / P0_R) to account for one-loop corrections in interacting theories, demonstrated in a three-phase SR-USR-SR setup for PBH formation.
In USR inflation with an idealized instantaneous sharp transition to slow-roll, higher loop corrections to curvature perturbations on CMB scales grow rapidly with loop order L and may exit perturbative control.
Improved end-of-inflation dynamics shift the Starobinsky model's predicted spectral index n_s by up to 1.2×10^{-3} within the allowed reheating range.
Ricci cosmology adds curvature-matter coupling terms to the stress-energy tensor, enabling analytic inflationary solutions in standard flat FLRW cosmology without Lambda or new scalar fields.
The equilateral bispectrum from massive scalar exchange in inflation is not universally negative in the full EFT of inflation; its sign depends on a critical ratio of operator coefficients.
Inflaton accretion during reheating drives non-linear PBH mass growth that extends lifetimes and amplifies emitted SGWB by multiple orders of magnitude.
The authors derive modified Friedmann equations from Kaniadakis entropy, compute inflationary observables, and find that Planck data require the deformation parameter kappa to be strongly suppressed in the standard case while allowing limited viable regions in the dual formulation.
Inflationary magnetic fields induce curvature perturbations that form ultralight PBHs, generating a stochastic GW background with model-specific features.
Adiabatic regularization combined with smoothed transitions suppresses the high-frequency oscillations in the power spectrum of primary gravitational waves about a zero mean.
A stable initial state is identified in mLQC-I that diagonalizes the Hamiltonian and minimizes particle creation, with mode functions approximated analytically by Airy or cylindrical functions whose constants are fixed by that state.
Reports f_NL = -20.5^{+19.0}_{-18.1} (68% CL) from combined Quaia quasar auto-correlation and CMB lensing cross-correlation assuming p_phi=1, or -28.7^{+26.1}_{-24.6} for p_phi=1.6.
Phase transitions in dark sectors can generate CMB B-modes with amplitudes competitive with inflation but peaking at smaller angular scales.
Einstein-Cartan pseudoscalaron inflation coupled to type-I seesaw neutrinos makes nonthermal leptogenesis a necessary mechanism for the baryon asymmetry, yielding ns ~ 0.97, r ~ 0.004 and nB/s ~ 8.7e-11 for gamma ~ -1/100 and lightest Majorana mass ~ 10^13 GeV.
NANOGrav data favors a blue-tilted tensor spectrum with nt ≈ 2.2, radiation-dominated reheating, and alpha-vacuum states over standard Bunch-Davies, with a frequency-dependent alpha suggested to resolve the blue-tilt tension.
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.
A spectator scalar field with strong portal coupling to the inflaton sources a stochastic gravitational wave background reaching Ω_GW h² ∼ 10^{-11} at frequencies 10^7-10^8 Hz for benchmark parameters σ/λ ≃ 10^4 and T_reh = 2×10^{14} GeV.
citing papers explorer
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Massive Exchange and the Sign of the Equilateral Bispectrum
The equilateral bispectrum from massive scalar exchange in inflation is not universally negative in the full EFT of inflation; its sign depends on a critical ratio of operator coefficients.
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Modified Gravity Theories on a Nutshell: Inflation, Bounce and Late-time Evolution
Modified gravity theories supply viable mathematical frameworks for inflation, bounces, and dark energy eras that match observational data.