REVIEW 6 cited by
Highly non-Gaussian tails and primordial black holes from single-field inflation
Not yet reviewed by Pith; the record is open.
This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.
SPECIMEN: schema-true, not a live event
T0 review · schema-true
One-sentence machine reading of the paper's core claim.
pith:XXXXXXXX · record.json · timestamp
read the original abstract
For primordial perturbations, deviations from Gaussian statistics on the tail of the probability distribution can be associated with non-perturbative effects of inflation. In this paper, we present some particular examples in which the tail of the distribution becomes highly non-Gaussian although the statistics remains almost Gaussian in the perturbative regime. We begin with an extension of the ultra-slow-roll inflation that incorporates a transition process, where the inflaton climbs up a tiny potential step at the end of the non-attractor stage before it converges to the slow-roll attractor. Through this example, we identify the key role of the off-attractor behaviour for the upward-step transition, and then extend the analysis to another type of the transition with two slow-roll stages connected by a tiny step. We perform both the perturbative and non-perturbative analyses of primordial fluctuations generated around the step in detail, and show that the tiny but nontrivial transition may affect large perturbations in the tail of the distribution, while the perturbative non-Gaussianity remains small. Our result indicates that the non-Gaussian tails can have rich phenomenology which has been overlooked in conventional analyses. We also study the implications of this non-Gaussian tail for the formation of primordial black holes, and find that their mass fraction can be parametrically amplified by several orders of magnitudes in comparison with the case of the Gaussian distribution. Additionally, we also discuss a mechanism of primordial black holes formation for this upward step inflation model by trapping the inflaton in the bottom of the step.
Forward citations
Cited by 6 Pith papers
-
Confronting infrared divergences in de Sitter: loops, logarithms and the stochastic formalism
The authors show that loop corrections do not alter tree-level time dependence in de Sitter correlators, so secular growth is a regularization artifact, not a physical effect.
-
Spectator Axions in String Inflation and Primordial Black Holes
In Fibre Inflation, spectator axions with f≲0.1 M_Pl leave the PBH power spectrum unchanged, while for f≳0.1 M_Pl and exponentially small non-perturbative prefactors they can raise P_R from 1.9e-4 to 3.5e-3 and enable...
-
Trispectrum in Extended USR Model with Transition to SR
In the two-phase USR-SR inflation model, g_NL = 25 h^3 / (3 (h-6)^3) and tau_NL = 9 h^4 / (h-6)^4, confirmed by both delta-N and in-in formalisms.
-
Axion USR Inflation
In axion inflation with an intermediate ultra-slow-roll phase, the instability parameter collapses at the start of USR, terminating gauge production and yielding a two-peak power spectrum with P_R ∝ k^m, m>4.
-
Constraining primordial non-Gaussianity and parity-violation through Scalar-Induced Gravitational Waves with next-generation ground-based interferometers
ET+CE forecast: injected SIGW parameters (A_p, f_peak, f_NL, tau_NL, parity-odd tau_tilde_NL) are recovered within 1-2 sigma despite an astrophysical foreground, but the chiral V-mode is sub-threshold (SNR 0.5-1.9).
-
Evolution of Linear Perturbations under Time-Dependent Hubble Friction I: SR-USR-SR Inflation
Analytic asymptotics show the dip in the SR-USR-SR curvature power spectrum comes from cancellation between two growing modes, not a constant-versus-growing cancellation.
Discussion (0). Sign in to comment.