Transcript 投影片 1 - National Tsing Hua University

Inflation after WMAP
Kin-Wang Ng (吳建宏)
Academia Sinica, Taiwan
2nd International Workshop on
Dark Matter, Dark Energy, and
Matter-Antimatter Asymmetry
Hsinchu, Nov 5 – 6 , 2010
Collaborators: Yeo-Yie Charng, Hing-Tong Cho, Da-Shin Lee, Wolung Lee,
I-Chin Wang, Chun-Hsien Wu
Outline
• Cosmic background backgroud anisotropy
and WMAP observation
• Primordial density perturbation
scale-invariant, running spectral index, Gaussianity
• Large-scale CMB anomalies
• Implications to inflation
7-year
WMAP 2010
PR(k)= (δρ/ρ)2
Running
spectral
index
Inflation and Primordial Density Fluctuations
H
PR(k)= (δρ/ρ)2
|dn/dlnk| << |n-1|
Curvature potential
▽2Φ=δρ/ρ
Slow-roll inflation
WMAP3 Data on
Non-Gaussianity
Radiation transfer function
Large-scale CMB anomalies
WMAP1
WMAP3
Low quadrupole
South-North Power Asymmetry
Eriksen et al 04
Park 04
Eriksen et al 04
northern hemisphere
southern hemisphere
full sky
North pole (80o,57o)
WMAP3
CMB sky map
Land & Magueijo 05
“Axis of Evil”
l=2, quadrupole
l=3, octopole
A Challenge to Standard Slow-roll inflation!?
Slow-roll kinematics
Slow-roll conditions
violated after horizon
crossing (Leach et al)
General slow-roll
condition (Steward)
|n-1|~|dn/dlnk|
Multi-field (Vernizzi, Tent,

Rigopoulos, Yokoyama et al)
etc
Quantum fluctuations
Chaotic inflation –
classical fluctuations driven
by a white noise (Starobinsky)
or by a colored noise

(Liguori, Matarrese et al.)
coming from high-k inflaton
Driven by a colored noise
from interacting quantum
environment (Wu et al)
 Trapped inflation (Green et al)
Our Inflaton-Scalar Interacting Model
Single-field inflation〈σ〉= 0
(Wu et al 07)
Trace out sigma field to obtain :
Feynman & Vernon 1963
Influence Functional Method
semi-classical
Dissipation
imaginary part
Colored,
dependent
on history
Noise
real part
Start of inflation
Dominant passive fluctuations and low CMB quadrupole
assuming no active de Sitter quantum fluctuations
Running spectral index and Non-gaussianity
• We propose a new dynamical source for density
perturbation: Colored Quantum Noise
- give a low CMB quadrupole
• Can be applied to trapped inflation (Green et al. 09)
• Working on running spectral index and nonGaussianity, both are natural with colored noise
ns
Dissipation?
Relative large
three-point functions
Following is an effort to go
from homogenous to
directional effects
A black hole in inflation Cho, Ng, Wang 09
Schwarzschild-de Sitter
M - black hole mass
H - Hubble parameter
Static ------> Planar
Inflaton
fluctuations
Expansion
parameter
where the source term
Solutions
Zero order
First order
Power spectrum
de Sitter
quantum fluctuations
End of inflation  → 0
Possible effects to CMB anisotropy
early universe
present universe
e.g. black holes
formed via
thermal
fluctuations
Scardigli et al.
Carroll, Tseng, & Wise 08 preferred point, line, or plane
Speculations
• Is it possible not to fine tune inflation
duration to 60 efolds?
• Then there must be something taking
place during slow-roll inflation
• Formation rate must not be far below the
expansion rate of inflation
• e.g. Collapse of density peaks of quantum
fluctuations during inflation or…
String Landscape
• 10500 de Sitter vacua
• Metastable, bubble nucleation via
tunneling
• Barriers of string scale, slow
tunneling rate
• The spacetime is a hierachy of de
Sitter vacuum bubbles
• Most part in eternal inflation
• Some regions tunnel down to flat
potential for slow-roll infaltion
• We sit in a vacuum with a small
cosmological constant today
Efficient and rapid tunneling
Tye, Shiu,…
slow-roll inflation in a de Sitter vauum Λ2
Λ1
Λ2
Will these bubbles Λ1 collapse
into black holes?
Motion of the bubble wall
surface
tension
bubble radius
Work is in progress towards
an explanation of
large-scale CMB anomalies
with
black holes, domain filaments,
and bubble walls
Conclusion
• Hints from WMAP data on beyond standard
slow-roll inflation !?
• A fine tuning – physics just at 60 e-foldings
• Maybe there is a window to see the first few efoldings of inflation !?
• Many models give a suppressed CMB low
multipoles and/or directional effects
• Perhaps we are all fooled by probability – it is
indeed a Gaussian quantum process
• Nongaussianity is an important check