Primordial density perturbations from the vector fields - PowerPoint PPT Presentation

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Primordial density perturbations from the vector fields

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Primordial density perturbations from the vector fields Mindaugas Kar iauskas in collaboration with Konstantinos Dimopoulos Jacques M. Wagstaff – PowerPoint PPT presentation

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Title: Primordial density perturbations from the vector fields


1
Primordial density perturbations from the vector
fields
  • Mindaugas Karciauskas
  • in collaboration with
  • Konstantinos Dimopoulos
  • Jacques M. Wagstaff

2
Plan
  • Hot Big Bang and its problems
  • Primordial perturbations
  • Inflation and CMB parameters
  • New observable statistical anisotropy
  • Vector curvaton model

3
The Universe After 1s
  • The Universe is expanding
  • Universe started being hot
  • Big bang nucleosynthesis
  • Large scale structure formation

4
The Universe After 1s
  • The Universe is expanding
  • Hubbles discovery 1929
  • Current measurements
  • Freedman et al. (2001)

5
The Universe After 1s
  • The early universe was hot
  • Discovery of the CMB
  • A. Penzias R. Wilson (1965)
  • Radiation which cooled downfrom 3000K to 2.7K
  • Steady State Cosmology is wrong

6
The Universe After 1s
  • Big Bang Nucleosynthesis
  • H, He, Li and Be formed during first 3 minutes
  • R. A. Alpher G. Gamow (1948)
  • Predictions span 9 orders of magnitude
  • Confirmed by CMB observationsat

7
The Universe After 1s
  • Large Scale Structure formation
  • Seed perturbations of theorder
  • Subsequent growth due to gravitational
    instability

8
Initial conditions for the Hot Big Bang
  • Horizon the universe is so uniform
  • Flatness the universe is so old
  • Primordial perturbations what is their origin

9
Inflation
  • Horizon the universe is so uniform
  • Flatness the universe is so old

gt Inflation
ll ll lt/
  • Primordial perturbations what is their origin

10
Superhorizon Density perturbations
TE cross correlation
  • Perturbations are superhorizon
  • One can mimic acousticpeaks
  • but not superhorizoncorrelations

Hu et al. (1997)
  • gt Inflation

Barreiro (2009)
11
CMB a Probe of Inflationary Physics
  • What are the properties of primordial density
    perturbations and what can they tell about
    inflation?
  • Random fields
  • The curvature perturbation
  • is conserved on super-horizon scales if
    .

12
Random Fields
  • Curvature perturbations random fields
  • Isotropic two point correlation function
  • isotropic gt
  • Momentum space

13
Correlation function
  • Two point correlator in momentum space
  • The shape of thepower spectrum
  • Inflation models gt
  • WMAP 5yr measurements
  • Errorbars small enough to rule out some
    inflationary models

14
Higher Order Correlators
  • Three point correlator
  • Non-Gaussianity parameter
  • Single field inflation gt Gaussian perturbations
  • WMAP 5yr measurements

15
Statistical Anisotropy
  • New observable
  • Anisotropic two point correlation
  • function
  • Anisotropic if for
  • The anisotropic power spectrum
  • The anisotropic bispectrum

16
Random Fields with Statistical Anisotropy
Isotropic
- preferred direction
17
Vector Field Model
  • Until recently only scalar fields were considered
    for production of primordial curvature
    perturbations
  • We consider curvature perturbations from vector
    fields

18
Vector Fields
  • Vector fields not considered previously because
  • Conformaly invariant gt cannot undergo particle
    production
  • Induces anisotropic expansion of the universe
  • Brakes Lorentz invariance
  • Solved by using massive vector field
  • Conformal invariance is broken
  • Oscillates and acts as pressureless isotropic
    matter
  • Decays before BBN

19
Vector Curvaton Scenario
  • The energy momentum tensor
  • Inflation
  • Light Vector Field
  • Heavy Vector Field
  • Vector Field Decay.Onset of Hot Big Bang

20
Particle Production
  • Lagrangian
  • De Sitter inflation with the Hubble parameter
  • Three degrees of freedom and
  • If and gt scale invariant
    perturbation spectra
  • At the end of inflation and

21
Power Spectra
22
Anisotropic Perturbations
  • Curvature perturbations statistically
    anisotropic
  • gt Vector contribution subdominant
  • Non-Gaussianity
  • Correlated with statistical anisotropy
  • Itself anisotropic
  • Smoking gun for the vector field contribution to
    the curvature perturbations.

Groeneboom et al. (2009)
23
No Scalar Fields
  • Curvature perturbations statistically isotropic
  • gt No need for other sources of perturbations.
  • Vector fields starts oscillating during
    inflation
  • Parameter space
  • Inflationary energy scale
  • Oscillations starts at least

24
Summary
  • Inflation most successful paradigm for solving
    HBB problems and explaining the primordial
    density perturbations
  • New observable statistical anisotropy
  • Massive vector curvaton model
  • Can produce the statistically anisotropic
    curvature perturbations
  • Non-Gaussianity is correlated with statistical
    anisotropy
  • Non-Gaussianity is itself anisotropic
  • Possible inflationary model building without
    scalar fields
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