Non-linear effects in early Universe cosmology

Abstract

In this thesis, we discuss several instances in which non-linear behaviour affects cosmological evolution in the early Universe. We begin by reviewing the standard cosmological model and the tools used to understand it theoretically and to compute its observational consequences. This includes a detailed exposition of cosmological perturbation theory and the theory of inflation. We then describe the results in this thesis, starting with the non-linear evolution of the curvature perturbation in the presence of vector and tensor fluctuations, in which we identify the version of that variable that is conserved in the most general situation. Next, we use second order perturbation theory to describe the most general initial conditions for the evolution of scalar perturbations at second order in the standard cosmological model. We compute approximate solutions valid in the initial stages of the evolution, which can be used to initialize second order Boltzmann codes, and to compute many observables taking isocurvature modes into account. We then move on to the study of the inflationary Universe. We start by analysing a new way to compute the consequences of a sudden transition in the evolution of a scalar during inflation. We use the formalism of quantum quenches to compute the effect of those transitions on the spectral index of perturbations. Finally, we detail the results of the exploration of a multi-field model of inflation with a non-minimal coupling to gravity. We study popular attractor models in this regime in both the metric and the Palatini formulations of gravity and find all results for both the power spectrum and bispectrum of fluctuations to closely resemble those of the single-field case. In all systems under study we discuss the effects of non-linear dynamics and their importance for the resolution of problems in cosmology.

arXiv comment219 pages, including appendices. 16 Figures. PhD thesis

References in corpus (144)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters
• Efficient Computation of CMB anisotropies in closed FRW models
• f(R) Theories Of Gravity
• Modified Gravity and Cosmology
• Non-Gaussian features of primordial fluctuations in single field inflationary models
• The Dynamics of General Relativity
• The 2dF Galaxy Redshift Survey: Power-spectrum analysis of the final dataset and cosmological implications
• The Standard Model Higgs boson as the inflaton
• Axion Cosmology
• The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations in the Data Release 10 and 11 galaxy samples
• Reheating after Inflation
• The 3D power spectrum of galaxies from the SDSS
• The Cosmic Microwave Background Spectrum from the Full COBE/FIRAS Data Set
• Three Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Polarization Analysis
• Generating the curvature perturbation without an inflaton
• MAXIMA-1: A Measurement of the Cosmic Microwave Background Anisotropy on angular scales of 10 arcminutes to 5 degrees
• Time-dependence of correlation functions following a quantum quench
• Non-Gaussianity from Inflation: Theory and Observations
• Quantum Contributions to Cosmological Correlations
• A new approach to the evolution of cosmological perturbations on large scales
• Equilibrium State of a Massless Self-Interacting Scalar Field in the De Sitter Background
• A general proof of the conservation of the curvature perturbation
• The primordial density perturbation in the curvaton scenario
• Nongaussian Isocurvature Perturbations from Inflation
• Formalising the Slow-Roll Approximation in Inflation
• Single field consistency relation for the 3-point function
• Cosmological perturbations
• A New Calculation of the Recombination Epoch
• The Dawn of FIMP Dark Matter: A Review of Models and Constraints
• The Cosmic Linear Anisotropy Solving System (CLASS) I: Overview
• The Unity of Cosmological Attractors
• f(R) Gravity and scalar-tensor theory
• Inflationary perturbations from a potential with a step
• Perturbations of spacetime: gauge transformations and gauge invariance at second order and beyond
• A universal attractor for inflation at strong coupling
• Particle physics models of inflation and curvaton scenarios
• The Energy-Momentum Tensor for Cosmological Perturbations
• Inflation with Non-Minimal Coupling: Metric vs. Palatini Formulations
• HyRec: A fast and highly accurate primordial hydrogen and helium recombination code
• Probing Planckian physics: resonant production of particles during inflation and features in the primordial power spectrum
• Analytic and Numerical Study of Preheating Dynamics
• Effective Field Theory of Cosmic Acceleration: an implementation in CAMB
• Non-minimal Inflationary Attractors
• Correlated adiabatic and isocurvature perturbations from double inflation
• xPerm: fast index canonicalization for tensor computer algebra
• The General Primordial Cosmic Perturbation
• Non-Equilibrium Quantum Fields in the Large N Expansion
• The Observed Squeezed Limit of Cosmological Three-Point Functions
• Super-Hubble de Sitter Fluctuations and the Dynamical RG
• The Separate Universe Approach and the Evolution of Nonlinear Superhorizon Cosmological Perturbations
• Six-dimensional Methods for Four-dimensional Conformal Field Theories
• Multifield Inflation after Planck: The Case for Nonminimal Couplings
• Large-scale curvature and entropy perturbations for multiple interacting fluids
• Higgs-Palatini Inflation and Unitarity
• Evolution of second-order cosmological perturbations
• Multi-field Conformal Cosmological Attractors
• Conformal Transformations with Multiple Scalar Fields
• Random Matrices and the Spectrum of N-flation
• General relativity and cosmic structure formation
• Quantum quench in interacting field theory: a self-consistent approximation
• Observational constraints on the curvaton model of inflation
• Phase transitions in the early and the present Universe
• Primordial Bispectrum from Multifield Inflation with Nonminimal Couplings
• Massive Neutrinos and Magnetic Fields in the Early Universe
• Higgs inflation with loop corrections in the Palatini formulation
• Dynamics of Assisted Inflation
• Integral Solution for the Microwave Background Anisotropies in Non-fl at Universes
• Non-Gaussianity from Step Features in the Inflationary Potential
• New Universal Local Feature in the Inflationary Perturbation Spectrum
• Conserved non-linear quantities in cosmology
• The Spectrum of Density Perturbations produced during Inflation to Leading Order in a General Slow-Roll Approximation
• Geometrical Destabilization of Inflation
• Dominance of gauge artifact in the consistency relation for the primordial bispectrum
• Primordial features due to a step in the inflaton potential
• Tachyonic preheating using 2PI-1/N dynamics and the classical approximation
• CMBFAST for spatially closed universes
• The full contribution of a stochastic background of magnetic fields to CMB anisotropies
• Effective potential for quantum scalar fields on a de Sitter geometry
• Re-Ionization and its Imprint on the Cosmic Microwave Background
• Second Order General Slow-Roll Power Spectrum
• Correlating features in the primordial spectra
• Evolution of cosmological dark matter perturbations
• The non-adiabatic pressure in general scalar field systems
• The Palatini side of inflationary attractors
• Generalized Slow Roll for Large Power Spectrum Features
• Nonlinear perturbations of cosmological scalar fields
• Multifield Inflation after Planck: Isocurvature Modes from Nonminimal Couplings
• The cosmic microwave background bispectrum from the non-linear evolution of the cosmological perturbations
• Must Cosmological Perturbations Remain Non-Adiabatic After Multi-Field Inflation?
• The Impact of Stochastic Primordial Magnetic Fields on the Scalar Contribution to Cosmic Microwave Background Anisotropies
• Standard Clock in Primordial Density Perturbations and Cosmic Microwave Background
• Scalar field correlator in de Sitter space at next-to-leading order in a 1/N expansion
• Inflationary Perturbations in Palatini Generalised Gravity
• Localized correlated features in the CMB power spectrum and primordial bispectrum from a transient reduction in the speed of sound
• Moment transport equations for non-Gaussianity
• Bounds on CDM and neutrino isocurvature perturbations from CMB and LSS data
• Simple predictions from multifield inflationary models
• Cosmological Perturbations at Second Order and Recombination Perturbed
• The intrinsic bispectrum of the Cosmic Microwave Background [PhD thesis]
• Compensated Isocurvature Perturbations and the Cosmic Microwave Background
• The CMB bispectrum from recombination
• The seed magnetic field generated during recombination
• Curvature perturbation in multi-field inflation with non-minimal coupling
• Inflationary dynamics and preheating of the non-minimally coupled inflaton field in the metric and Palatini formalisms
• Vorticity generation at second order in cosmological perturbation theory
• Boltzmann hierarchy for the cosmic microwave background at second order including photon polarization
• A Concise Introduction to Perturbation Theory in Cosmology
• Simulations of Cold Electroweak Baryogenesis: Finite time quenches
• Primordial Perturbations from Multifield Inflation with Nonminimal Couplings
• Relativistic Interpretation of Newtonian Simulations for Cosmic Structure Formation
• Transport equations for the inflationary spectral index
• Cold Dark Matter Isocurvature Perturbations: Constraints and Model Selection
• The curvature perturbation at second order
• Compensated isocurvature perturbations in the curvaton model
• Mild bounds on bigravity from primordial gravitational waves
• Transport equations for the inflationary trispectrum
• Isocurvature modes in the CMB bispectrum
• Simple emergent power spectra from complex inflationary physics
• Post-Newtonian parameter $\gamma$ for multiscalar-tensor gravity with a general potential
• Can cosmological perturbations produce early universe vorticity?
• Random Potentials and Cosmological Attractors
• Nonlinear perturbations for dissipative and interacting relativistic fluids
• Physical momentum representation of scalar field correlators in de Sitter space
• Consistency relations for sharp features in the primordial spectra
• The effects of a fast-turning trajectory in multiple-field inflation
• Estimating the amount of vorticity generated by cosmological perturbations in the early universe
• Parameterization of temperature and spectral distortions in future CMB experiments
• A Direct Probe of the Evolutionary History of the Primordial Universe
• Covariant generalization of cosmological perturbation theory
• Vector and tensor contributions to the curvature perturbation at second order
• Lensing Bias to CMB Measurements of Compensated Isocurvature Perturbations
• A precise numerical estimation of the magnetic field generated around recombination
• Out of Equilibrium Non-perturbative Quantum Field Dynamics in Homogeneous External Fields
• Modification of late time phase structure by quantum quenches
• Primordial magnetic fields generated by the non-adiabatic fluctuations at pre-recombination era
• PyTransport: A Python package for the calculation of inflationary correlation functions
• What Planck does not tell us about inflation
• Quantum quenches during inflation
• A short note on the curvature perturbation at second order
• Conserved Quantities in Lemaitre-Tolman-Bondi Cosmology
• A note on the initial conditions within the effective field theory approach of cosmic acceleration
• Local gauge-invariance at any order in cosmological perturbation theory

Cited by in corpus (1)

• Applications of Cosmological Perturbation Theory in the Late Universe