CMB Polarization

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CMB Polarization

• A New Tool for Cosmology Fundamental Physics
• James G. Bartlett
• APC - Université Paris 7

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We are approaching the ultimate limit on CMB
temperature measurements with WMAP and Planck
(2007)
The next major step is to measure the
polarization anisotropy important fundamental
science
This is happening now
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CMB Polarization a new tool

• The CMB and Cosmology
• CMB polarization anisotropies
• Origin
• Description (E B modes)
• Their use
• Primordial gravity waves
• Lensing (dark energy, neutrino mass)
• Observational effort

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The CMB and Cosmology
GUT?
Perturbations

• density (scalar)

• gravity waves (tensor)

Dark Energy
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(douspis)
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State of the Art (Spergel et al 02)
6 parameters flat
No running WMAPextLSS
WMAPext LSS
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The Planck Mission (2007)
(Planck Blue Book)
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CMB Polarization Anisotropies
Hu White 97
Thompson scattering in the plasma

• Linear polarization
• Local quadrupole anisotropy
• Finite optical depth

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Two Kinds of Spatial Patterns
E-modes (even parity)
Density perturbations
Gravity waves
B-modes (odd parity)
Gravity waves
Gravitational lensing
Zaldarriaga
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Decomposition into parity states (E B)
Even parity
On the sphere
Odd parity
Four possible spectra
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Importance of decomposition

• T (intensity), E B call all be measured
  separately
• They isolate different physical processes

E spectrum
T spectrum
B spectrum
Cross TE spectrum
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Produced with CAMB
Gravity Waves
Scalar T
Tensor T
Scalar TE
Scalar E
Tensor B
Fiducial WMAP Model
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Lensing
Hu Okamoto astro-ph/ 0111606
(Zaldarriaga Seljak 1998 Bernardeau
1997 Blanchard Schneider 1987)
10 degs
Lensed E field
Unlensed E field
B-mode induced by lensing of E-mode
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Produced with CAMB
Grav. Lensing
Weak lensing signal
dark energy
Fiducial WMAP Model
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Uses of CMB Polarization

• Constraining ICs tighter
• constraints on params
• Gravity waves from
• Inflation
• nature of gravity
• test of inflation
• energy scale
• Planck-era physics?
• Lensing reconstruction
• constraints on Dark Energy
• neutrino mass measurement

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Observational Effort
E TE modes first detected by DASI Kovac et al.
2002
Oliveira-Costa et al. 02
(South Pole Station)
J. Carlstrom
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WMAP
TE cross power spectrum
Kogut et al. 2003
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BOOMERanG 03
MacTavish et al. 0507503
CMBallB03LSS
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CBI
Sievers et al. 0509203
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Planck Polarization
(Planck Blue Book)
TE cross spectra
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Planck Polarization
(Planck Blue Book)
E spectra
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Planck Polarization
(Planck Blue Book)
Grav. Waves
Lensing
B spectra
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Long-term Effort
Bowden et al. 04
2005
BICEP QUaD
Ground/ balloon
2008-2010
ClOVER EBEX PolarBear QUIET SPIDER
Taylor et al. 04
Ganga 04
Grav. Waves
gt2015
Dark Energy
CMBpol (NASA ESA) SAMPAN (CNES)
(Kaplinghat et al. 2003)
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Neutrino mass
Fogli et al. 2005
Should measure Something!!
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Conclusions

• Exciting Science
• Constraining ICs tighter
• constraints on params
• Gravity waves from
• Inflation
• nature of gravity
• test of inflation
• energy scale
• Planck-era physics?
• Lensing reconstruction
• constraints on Dark Energy
• neutrino mass measurement
• Currently
• Several measurements EE, TE
• Boomerang 03
• Adiabatic seems good

• Challenges
• Sensitivity
• Systematics
• Foregrounds TE, EE not so bad, it would seem (on
  small well-chosen patches) BB??

Orders of mag.to be gained