We report on a novel phenomenon of the resonance effect primordial density perturbations arisen from sound speed parameter with an oscillatory behavior, which can generically lead to formation black holes in early Universe. For general inflaton field, it seed fluctuations and their propagation is governed by square. Once if this achieves feature for while during inflation, significant non-perturbative field takes place around critical length scale, results peaks power spectrum. By virtue...

Abstract Primordial non-Gaussianities from multi-field inflation are a leading target for cosmological observations, because of the possible large correlations generated between long and short distances. These signatures captured by local shape scalar bispectrum. In this paper, we revisit nonlinearities conversion process additional light scalars into curvature perturbations during inflation. We provide analytic templates correlation functions valid at any kinematical configuration, using...

Non-attractor inflation is known as the only single field inflationary scenario that can violate non-Gaussianity consistency relation with Bunch-Davies vacuum state and generate large local non-Gaussianity. However, it also non-attractor by itself incomplete should be followed a phase of slow-roll attractor. Moreover, there transition process between these two phases. In past literature, this was approximated instant evolution in not fully studied. paper, we follow detailed through into...

As potential candidates of dark matter, primordial black holes (PBHs) are within the core scopes various astronomical observations. In light explosive development gravitational wave (GW) and radio astronomy, we thoroughly analyze a stochastic background cosmological GWs, induced by overly large density perturbations, with several spikes that was inspired sound speed resonance effect can predict particular pattern on mass spectrum PBHs. With specific mechanism for PBH formation, first time...

We report on the first joint analysis of observational signatures from electroweak baryogenesis in both gravitational wave (GW) detectors and particle colliders. With an effective extension Higgs sector terms dimension-six operators, we derive a strong first-order phase transition associated with sizable CP violation to realize successful baryogenesis. calculate GW spectrum resulting bubble nucleation, plasma transportation, magnetohydrodynamic turbulence this process that occurred after big...

A bstract Cosmological correlation functions contain valuable information about the primordial Universe, with possible signatures of new massive particles at very high energies. Recent developments, including cosmological bootstrap, bring perspectives and powerful tools to study these observables. In this paper, we systematically classify inflationary three-point correlators scalar perturbations using bootstrap method. For first time, derive a complete set single-exchange collider bispectra...

Abstract For primordial perturbations, deviations from Gaussian statistics on the tail of probability distribution can be associated with non-perturbative effects inflation. In this paper, we present some particular examples in which becomes highly non-Gaussian although remains almost perturbative regime. We begin an extension ultra-slow-roll inflation that incorporates a transition process, where inflaton climbs up tiny potential step at end non-attractor stage before it converges to...

We report a novel prediction from single-field inflation that even tiny step in the inflaton potential can change our perception of primordial non-Gaussianities curvature perturbation. Our analysis focuses on tail probability distribution generated by an upward transition between two stages slow-roll evolution. The nontrivial background dynamics with off-attractor behavior is identified. By using non-perturbative $\delta N$ analysis, we explicitly show highly non-Gaussian be step, when...

A bstract In this paper, we revisit the infrared (IR) divergences in de Sitter (dS) space using wavefunction method, and explicitly explore how resummation of higher-order loops leads to stochastic formalism. light recent developments cosmological bootstrap, track behaviour these nontrivial IR effects from perturbation theory non-perturbative regime. Specifically, first examine perturbative computation coefficients, show that there is a clear distinction between classical components...

Abstract In this paper, we present the first comprehensive CMB data analysis of cosmological collider physics. New heavy particles during inflation can leave imprints in primordial correlators which are observable today's surveys. This remarkable detection channel provides an unsurpassed opportunity to probe new physics at extremely high energies. Here initiate search for these relic signals cosmic microwave background (CMB) from Planck legacy release. On theory side, guided by recent...

We study a particular version of the theory cosmological α-attractors with α=1/3, in which both dilaton (inflaton) field and axion are light during inflation. The kinetic terms this originate from maximal =4 superconformal symmetry =8 supergravity. show that because underlying hyperbolic geometry moduli space theory, it exhibits double attractor behavior: their predictions stable not only respect to significant modifications potential, but also potential: ns≃1−2/N, r≃4/N2. universality...

A bstract Our understanding of quantum correlators in cosmological spacetimes, including those that we can observe surveys, has improved qualitatively the past few years. Now know many constraints these objects must satisfy as consequences general physical principles, such symmetries, unitarity and locality. Using this new understanding, derive most scalar four-point correlator, i.e., trispectrum, to all orders derivatives for manifestly local contact interactions. To obtain result use...

We study the effects of non-attractor initial conditions for canonical single-field inflation. The stage can last only several $e$-folding numbers, and should be followed by hilltop This two-stage evolution leads to large scale suppression in primordial power spectrum, which is favored recent observations. Moreover we give a detailed calculation non-Guassianity due "from slow-roll" transition, find step features local equilateral shapes. conclude that plateau-like inflaton potential with an...

We review matter bounce scenarios where the content is dark and energy. These cosmologies predict a nearly scale-invariant power spectrum with slightly red tilt for scalar perturbations small tensor-to-scalar ratio. Importantly, these models positive running of index, contrary to predictions simplest inflationary ekpyrotic models, hence could potentially be falsified by future observations. also how bouncing cosmological space-times can arise in theories either Einstein equations are...

We construct a model of natural inflation in the context α-attractor supergravity, which both dilaton field and axion are light during inflation, inflaton may be combination two. The T-model version this theory is defined on Poincaré disk with radius |Z| = 1. It describes Mexican hat potential flat direction corresponding to circle < decay constant fa can exponentially large because hyperbolic geometry disk. Depending initial conditions, describe driven by radial component field, or sequence...

We present a new class of two-field inflationary attractor models, known as shift-symmetric orbital inflation, whose behavior is strongly multifield but predictions are remarkably close to those single-field inflation. In these the field space metric and potential such that inflaton trajectory along an ``angular'' isometry direction ``radius'' constant arbitrary. As result, radial (isocurvature) perturbations away from exactly massless they freeze on superhorizon scales. These models first...

Massive fields during inflation provide an interesting opportunity to test new physics at very high energy scales. Meanwhile in fundamental realizations, the inflationary field space typically has a curved geometry, which may leave detectable imprints primordial observables. In this paper we study extension of quasi-single where inflaton and massive belong manifold. Because nontrivial curvature, here can get significant mass corrections order Hubble scale, thus predictions on non-Gaussianity...

We extend the matter bounce scenario to a more general theory in which background dynamics and cosmological perturbations are generated by $k$-essence scalar field with an arbitrary sound speed. When speed is small, curvature perturbation enhanced, tensor-to-scalar ratio, excessively large original model, can be sufficiently suppressed consistent observational bounds. Then, we study primordial three-point correlation function during matter-dominated contraction stage find that it only...

The matter bounce scenario allows for a sizable parameter space where cosmological fluctuations originally exited the Hubble radius when background energy density was small. In this and its extended versions, low degrees of freedom are likely responsible statistical properties cosmic microwave power spectrum at large length scales. An interesting consequence is that these modes might be observable only relatively late times. Therefore redshift observations could provide evidence for, or even...

Abstract Objective To derive age- and sex-specific reference values for waist circumference (WC) waist-to-height ratio (WHtR) Han Chinese children adolescents to establish the prevalence of excess central adiposity in our study population. Design Cross-sectional schoolchildren attending randomly selected primary secondary schools south-west China October 2003 April 2004. Anthropometry was measured using standard procedures. The LMS method used construct smoothed WC WHtR percentile curves....

The spectrum of relic gravitational wave (RGW) contains high-frequency divergences, which should be removed. We present a systematic study the issue, based on exact RGW solution that covers five stages, from inflation to acceleration, each being power law expansion. show consists vacuum dominating at $f>10^{11}$Hz and graviton $f<10^{11}$Hz, respectively. gravitons are produced by four cosmic transitions, mostly inflation-reheating one. perform adiabatic regularization remove divergences in...

We explore preheating in multi-field models of inflation which the field-space metric is a highly curved hyperbolic manifold. One broad family such called α-attractors, whose single-field regimes have been extensively studied context and supergravity. focus on simple two-field generalization T-model, has received renewed attention literature. Krajewski et al. concluded, using lattice simulations, that effects can dramatically speed-up preheating. recover their results further demonstrate...

We analyze and compare the multi-field dynamics during inflation preheating in symmetric asymmetric models of $α$-attractors, characterized by a hyperbolic field-space manifold. show that generalized (asymmetric) E- (symmetric) T-models exhibit identical two-field for wide range initial conditions. The resulting motion can be decomposed two approximately single-field segments connected sharp turn field-space. details nevertheless different. For T-model one main mass-scale dominates evolution...

We explore a plausible mechanism that the hemispherical power asymmetry in CMB is produced by spatial variation of primordial sound speed parameter. suggest generalized approach δ N formalism local e-folding number may depend on some other parameters besides initial values inflaton. Here extended considering effects spatially varying parameter caused super-Hubble perturbation light field. Using this formalism, we systematically calculate asymmetric spectrum model multi-speed inflation taking...