Hybrid inflation's waterfall tachyonic instability grows isocurvature modes that convert to curvature perturbations at the field-space turn, yielding a k^{3}-peaked spectrum with always-positive f_NL that enhances PBH formation.
Inflation with a constant rate of roll
7 Pith papers cite this work, alongside 240 external citations. Polarity classification is still indexing.
7
Pith papers citing it
240
external citations · Pith
abstract
We consider an inflationary scenario where the rate of inflaton roll defined by $\ddot\phi/H\dot \phi$ remains constant. The rate of roll is small for slow-roll inflation, while a generic rate of roll leads to the interesting case of `constant-roll' inflation. We find a general exact solution for the inflaton potential required for such inflaton behaviour. In this model, due to non-slow evolution of background, the would-be decaying mode of linear scalar (curvature) perturbations may not be neglected. It can even grow for some values of the model parameter, while the other mode always remains constant. However, this always occurs for unstable solutions which are not attractors for the given potential. The most interesting particular cases of constant-roll inflation remaining viable with the most recent observational data are quadratic hilltop inflation (with cutoff) and natural inflation (with an additional negative cosmological constant). In these cases even-order slow-roll parameters approach non-negligible constants while the odd ones are asymptotically vanishing in the quasi-de Sitter regime.
citation-role summary
background 3
citation-polarity summary
years
2026 7roles
background 3representative citing papers
Analytical formulae for power spectrum peaks in constant-roll inflation enable parameter reconstruction from peak features and smoothed approximations for induced gravitational wave estimates.
Spectral solution of the Fokker-Planck operator for hilltop constant-roll inflation shows rare crossing trajectories dominate the mean, so the median yields a coarse-grained ΔN distribution whose exponential tail flattens into a peak near maximal value.
A new eigenvalue method is introduced to compute the PDF of stochastic e-folds in inflation, recovering a known flat-potential result and analyzing constant-drift cases in narrow and broad well limits.
Thermal backreaction modifies de Sitter geometry so that late-exiting modes produce a blue-tilted spectrum n_S ~ 2 while the boundary theory matches the 3d Sp(N) model flow.
Exponential and sech Gauss–Bonnet couplings restore ACT-compatible ns and r for quintessential inflation, while tanh fails for a structural sign reason; reheating remains BBN-safe.
An exactly solvable inflation model with negative cosmological constant from quantum cosmology is tested against Planck, ACT, and DESI data.
citing papers explorer
-
Superhorizon curvature perturbations in hybrid inflation revisited
Hybrid inflation's waterfall tachyonic instability grows isocurvature modes that convert to curvature perturbations at the field-space turn, yielding a k^{3}-peaked spectrum with always-positive f_NL that enhances PBH formation.
-
Constant-Roll Inflation: Analytical Formulae for Power Spectrum and Implications for Induced Gravitational Waves
Analytical formulae for power spectrum peaks in constant-roll inflation enable parameter reconstruction from peak features and smoothed approximations for induced gravitational wave estimates.
-
Stochastic constant-roll inflation beyond the hilltop with the spectral method
Spectral solution of the Fokker-Planck operator for hilltop constant-roll inflation shows rare crossing trajectories dominate the mean, so the median yields a coarse-grained ΔN distribution whose exponential tail flattens into a peak near maximal value.
-
Eigenvalue formulation of Stochastic Inflation and application to large perturbation generating inflationary features
A new eigenvalue method is introduced to compute the PDF of stochastic e-folds in inflation, recovering a known flat-potential result and analyzing constant-drift cases in narrow and broad well limits.
-
The thermal backreaction of a scalar field in de Sitter spacetime. II. Spectrum enhancement and holography
Thermal backreaction modifies de Sitter geometry so that late-exiting modes produce a blue-tilted spectrum n_S ~ 2 while the boundary theory matches the 3d Sp(N) model flow.
-
Constraining Quintessential Inflation with ACT: A Gauss-Bonnet Gateway
Exponential and sech Gauss–Bonnet couplings restore ACT-compatible ns and r for quintessential inflation, while tanh fails for a structural sign reason; reheating remains BBN-safe.
-
Natural Inflation with a negative cosmological constant
An exactly solvable inflation model with negative cosmological constant from quantum cosmology is tested against Planck, ACT, and DESI data.