Quantum diffusion and large primordial perturbations from inflation

Abstract

Quantum diffusion describes the inflow of vacuum quantum fluctuations as they get amplified by gravitational instability, and stretched to large distances during inflation. In this picture, the dynamics of the universe's expansion becomes stochastic, and the statistics of the curvature perturbation is encoded in the distribution of the duration of inflation. This provides a non-perturbative framework to study cosmological fluctuations during inflation, which is well-suited to the case of primordial black holes since they originate from large fluctuations. We show that standard, perturbative expectations for the primordial black hole abundance can be significantly modified by quantum-diffusion effects, and we identify a few open challenges.

Invited chapter to the book "Primordial Black Holes'', Springer 2024, ed. Chris Byrnes, Gabriele Franciolini, Tomohiro Harada, Paolo Pani, Misao Sasaki. 22 pages, 3 figures, matches published version

References in corpus (59)

• A General Analytic Formula for the Spectral Index of the Density Perturbations produced during Inflation
• A new approach to the evolution of cosmological perturbations on large scales
• A general proof of the conservation of the curvature perturbation
• Cosmological perturbations
• The inflationary prediction for primordial non-gaussianity
• Semiclassicality and Decoherence of Cosmological Perturbations
• Super-Horizon Scale Dynamics of Multi-Scalar Inflation
• Black hole formation in the Friedmann universe: Formulation and computation in numerical relativity
• Observation of critical phenomena and self-similarity in the gravitational collapse of radiation fluid
• Adiabatic Modes in Cosmology
• Threshold for primordial black holes: Dependence on the shape of the cosmological perturbations
• Critical behaviour in gravitational collapse of radiation fluid --- A renormalization group (linear perturbation) analysis ---
• Correlation Functions in Stochastic Inflation
• Enhancement of superhorizon scale inflationary curvature perturbations
• The Separate Universe Approach and the Evolution of Nonlinear Superhorizon Cosmological Perturbations
• Cosmological long-wavelength solutions and primordial black hole formation
• Quantum-to-classical Transition of Cosmological Perturbations for Non-vacuum Initial States
• Quantum diffusion during inflation and primordial black holes
• The exponential tail of inflationary fluctuations: consequences for primordial black holes
• Conserved cosmological perturbations
• Quantum Discord of Cosmic Inflation: Can we Show that CMB Anisotropies are of Quantum-Mechanical Origin?
• On the divergences of inflationary superhorizon perturbations
• A Fluctuation-Dissipation Relation for Semiclassical Cosmology
• Non-Gaussian tail of the curvature perturbation in stochastic ultra-slow-roll inflation: implications for primordial black hole production
• Non-linear perturbations in multiple-field inflation
• Non-perturbative non-Gaussianity and primordial black holes
• Ultra-slow-roll inflation with quantum diffusion
• Stochastic Inflation:The Quantum Phase Space Approach
• Stochastic inflation in phase space: Is slow roll a stochastic attractor?
• Stochastic inflation beyond slow roll
• A new algorithm for calculating the curvature perturbations in stochastic inflation
• Implications of stochastic effects for primordial black hole production in ultra-slow-roll inflation
• Obstructions to Bell CMB Experiments
• Highly non-Gaussian tails and primordial black holes from single-field inflation
• Stochastic Ultra Slow Roll Inflation
• Power spectrum in stochastic inflation
• Primordial black holes from stochastic tunnelling
• Minimal decoherence from inflation
• A manifestly covariant theory of multifield stochastic inflation in phase space: solving the discretisation ambiguity in stochastic inflation
• Statistics of coarse-grained cosmological fields in stochastic inflation
• Bell's Inequalities for Continuous-Variable Systems in Generic Squeezed States
• Statistical nature of infrared dynamics on de Sitter background
• Influence of Super-Horizon Scales on Cosmological Observables Generated during Inflation
• Stochastic constant-roll inflation and primordial black holes
• Discord and Decoherence
• Stochastic Inflation Revisited: Non-Slow Roll Statistics and DBI Inflation
• Stochastic inflation at all order in slow-roll parameters: foundations
• The separate-universe approach and sudden transitions during inflation
• Real-space entanglement in the Cosmic Microwave Background
• Gradient expansion approach to nonlinear superhorizon perturbations II -- a single scalar field --
• Can all the infrared secular growth really be understood as increase of classical statistical variance?
• Highly asymmetric probability distribution from a finite-width upward step during inflation
• Bipartite temporal Bell inequalities for two-mode squeezed states
• Clustering of primordial black holes from quantum diffusion during inflation
• Uphill inflation
• Primordial black hole compaction function from stochastic fluctuations in ultra-slow-roll inflation
• Real-space Bell inequalities in de Sitter
• Stochastic Inflation in General Relativity
• Computing First-Passage Times with the Functional Renormalisation Group

Cited by in corpus (9)

• Large fluctuations and Primordial Black Holes
• Stochastic inflation with gradient interactions
• Stochastic inflation and non-perturbative power spectrum beyond slow roll
• Itô, Stratonovich, and zoom-in schemes in stochastic inflation
• Dip and non-linearity in the curvature perturbation from inflation with a transient non-slow-roll stage
• Primordial black holes from a curvaton: the role of bimodal distributions
• Improved model of large-field inflation with primordial black hole production in Starobinsky-like supergravity
• Eternal inflation near inflection points: a challenge to primordial black hole models
• Effect of stochastic kicks on primordial black hole abundance and mass via the compaction function