Surveying Inflation and Reheating

Cosmological Landscape: Strings, Gravity and Inflation Seoul, September 2005

“K. listened intently. So the Castle had appointed him land surveyor …”

“The Castle” by F.Kafka

Lev Kofman, CITA

Bottom-up approach to inflation:reconstruction of acceleration trajectories

Top-down approach to inflation:seeks to embed it in fundamental theory

Early Universe Inflation

Scale factor

time

Realization of Inflation

Phase portrait of inflation

Particlegenesis

time

Inflation

no entropyno temperature

BANG

Occupation number

Classical Quantum

Resonant Preheating in Chaotic Inflation

Resonant Preheating in Chaotic Inflation

Classical Quantum

Decay of inflatonand preheating after inflation

movieFelder, LK,05

Classical Quantum

Decay of inflatonand preheating after inflation

Tachyonic Preheating in Hybrid Inflation

l

movie

Felder, LK, Linde,01

Tachyonic Preheating

inflationHot FRW

Initial conditions from Inflation

Modulated Fluctuations

Hà1

x~

î ÿ(x~)

î ÿ =Rd3k(akÿk(t)eik

~x~+h:c:)

t

Light field at inflation

Inflation radiation

LK03;Dvali et al,03

Modulated fluctuations in Chaotic Inflation

Podolsky, Felder, LK,Pelosohep-ph/0507096

Modulated fluctuations in Hybrid Inflation

inhomogeneous waterfall

Bernardeau, Uzan, LK 03

4 dimensional Inflation predicts

No classical inhomogeneities from the past

Scale free gaussian fluctuations of all light scalars

No vector perturbations

Scalar (almost scale free gaussian) metric perturbations

Tensor (scale free gaussian) metric perturbations

Creation of all SM particles in preheating/thermalization

Òtot =1

Cö÷úû = 0

î ÿk(t)eik~x~

Aö =0

Ð ! Ðk(t)eik~x~

hik ! hk(t)eik~x~eij

Treh

One inflation helps to ignite another inflation

Inflation in the context of ever changing fundamental theory

1980

2000

1990

-inflation Old Inflation

New Inflation Chaotic inflation

Double InflationExtended inflation

DBI inflation

Super-natural Inflation

Hybrid inflation

SUGRA inflation

SUSY F-term inflation SUSY D-term

inflation

SUSY P-term inflation

Brane inflation

K-flationN-flation

Warped Brane inflation

inflation

Power-law inflation

Tachyon inflationRacetrack inflation

Assisted inflation

Search for inflaton with branes in extra dimensions

4-dim picture

Dvali,Tye 98

Prototype of hybrid inflation

Compactification of inner dimensions with branes

Old string theory

New phenomenology

Strongly warped 5d geometry

ds2 = A2(y)(à dt2+dx~2) +gabdyadyb

RS 99

Stabilization of Inner dimensionsand moduli in string theory

dS4 â M

ds2 = A2(y)(à dt2+e2Htdx~2) +gabdyadyb

Realization of String Theory Chaotic Inflation

Mobile brane

Chaotic inflation

Realization of String Theory Inflation

on the ground of KKLT throat warped geometry

Mobile brane

modulated fluctuations

Conformal coupling problem

scalar field associated with angular position at

KKLMMT03

Warped brane inflation

Realization of warped brane inflation with conformal inflaton

Reheating after String Theory Inflation

Barnaby, Burgess, Cline, hep-th/0412095

LK, Yi, hep-th/0507257

Frey, Mazumdar, Myers, hep-th/0508139

Chialva, Shiu, Underwood, hep-th/0508229

Open strings

between branes are unstable

End point of inflation

BANG

SM particles

Closed strings

Unstable KK modes

Long-living KK modesrelated to inner isometries

LK, Yi 05

KK story

KK particles are thermalized firstSM particles are thermalized much later

KK from M with isometriesare stable

No complete decya

KK particles freeze out

KK

KK

KK

KK

SM

4 dim Inflation in 10dim String Theory predicts

All what 4 dim inflation predicts

Scale free gaussian fluctuations of many light scalars

Creation of non-SM particles (KK modes) in reheating/thermalization

î ÿk(t)eik~x~

TK K

Short-wavelength gravitational radiation

Modulated cosmological fluctuations

String theory Cosmic strings

string theoristCY

AdS3+1 FRW

Fluctuations in Cosmology with Compactification

string theoristCY

AdS3+1 FRW

3+1 FRW

Fluctuations in Cosmology with Compactification

CYcosmologist

string theorist

Practical cosmologist

CY

AdS

CY +fluctuations

3+1 FRW

3+1 FRW

3+1 FRW +fluctuations

Fluctuations in Cosmology with Compactification

CYcosmologist

background

fluctuations

Fluctuations in Cosmology with Compactification

ds2=A2(y)[(à dt2+e2Htdx~2) +gabdyadyb]

dS4 â M

Gravitational instability of anysotropocgeometry

Too strong fluxes lead to new instability

Summary

Theory of cosmological fluctuations in models withextra dimensions

Generic properties of fluctuations in 3+1+d dim

Instabilities exclude regions of landscape

Potential observables: varying couplings/masses,Primordial fluctuations

Scanning Inflation R.Bond, C.Contaldi,A.Frolov, L.KofmanT.SouradeepP.Vandrevange

Bottom-up

Ensemble of Inflationary trajectories

Chebyshev decomposition

Space of models opens wide

H(N) P(k)

ns;nt; r;dn=dlnk;As; :::

ï ;ñ:::

Observational constraints on trajectories

Markov Chain Monte Carlo

Degeneracy of the Potential Reconstruction

“Best fit” model is awkward:

features in the potential

suppression of scalar mode at large scales

large tensor mode

Bottom-up:personal priors

Top-down approach:no priors

Non-vanishing probability

Reconstruction of Inflationary Trajectory