CMB lensing and cosmic acceleration

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CMB lensingand cosmic acceleration

• Viviana Acquaviva
• SISSA, Trieste

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Outline

• Physics of lensing
• From CMB to dark energy
• Results and forecasts

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geodesic equation
Einstein equations
small deflection angles ? WEAK LENSING
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why lensing for dark energy?
us
r/H0-1
2
1
0
5
CMB lensing phenomenology
re-mapping
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Temperature power spectrum
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B polarization modes power spectrum
reionization
primordial GW
lensing
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B polarization modes power spectrum
unbiased observable, tracking DE at lensing epoch
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plan of our work

• Formal extension of lensing framework
• to generalized theories of gravity

VA, Baccigalupi and Perrotta 2004
2. Study of lensed B signal in different models
RP V(?) M4?/?? (aka IPL) Ratra
Peebles 2000 SUGRA V(?) M4?/?? e4?(?/Mpl)2
Brax Martin 2000
VA Baccigalupi 2005
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technicalities ?
lensed correlation functions are obtained by a
convolution with a gaussian of arguments
Zaldarriaga Seljak 1998
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RESULTS FOR THE QUINTESSENCE MODELS
no anisotropic stress basically geometry effects
tracking behaviour ? main dependence is on a
w0 - 0.9
tuned to get Geff G0
SAME PRIMORDIAL NORMALIZATION
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Lensing kernel
different amount of dark energy at z 1
? significant deviation
Perturbation growth factor
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TT power spectrum
only slight projection effect
EE power spectrum
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COMPARISON OF B-MODES SPECTRA
IPL
SUGRA
30 difference in amplitude at peak
effect is due to B-modes sensitivity to DE
equation of state DERIVATIVE!
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GETTING MORE QUANTITATIVE A FISHER MATRIX
ANALYSIS
ESTIMATOR OF ACHIEVABLE PRECISION
set of parameters ai
single spectrum
four spectra
F-1ij gives marginalized 1-s error on parameters
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dark energy parametrization
Chevallier Polarski 2001, Linder Huterer 2005
fixing primordial normalization one has only
projection effects on TT,TE,EE spectra
B spectrum ? amplitude changes! ?
(sensitivity to dynamics at lower redshifts)
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PARAMETERS
?CDM
SUGRA

• w0 -1
• w8 -1
• ns 0.96
• h0 0.72
• t 0.11
• Obh2 0.022
• Om h2 0.11
• A 1

• w0 -0.9
• w8 -0.4
• ns 0.96
• h0 0.72
• t 0.11
• Obh2 0.023
• Om h2 0.12
• A 1

EBEX-like experiment
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v(F-1)ii
0.1
?CDM RESULTS
few 10-2
w0
310-3
610-2
w
310-3
5 10-2
810-5
ns
h0
710-4
few10-2
t
310-3
Obh2
210-3
210-2
Omh2
310-3
A
710-5
SUGRA RESULTS
510-4
v(F-1)ii
5.010-3
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CONCLUSIONS AND FURTHER THOUGHTS

• We can extract valuable information from
• the lensed CMB spectra
• The B-modes are the most faithful tracer
• of the dark energy behaviour at intermediate
• redshifts and can discriminate among models
• We have a computational machine allowing us
• to predict the lensed spectra of a wide
  range
• of models
• We expect to be able to rule out or select
• models thanks to the next generation of CMB
• polarization-devoted experiments
• (EBEX, CMBpol, PolarBEar)

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CONCLUSIONS AND FURTHER THOUGHTS

• We can extract valuable information from
• the lensed CMB spectra
• The B-modes are the most faithful tracer
• of the dark energy behaviour at intermediate
• redshifts and can discriminate among models
• We have a computational machine allowing us
• to predict the lensed spectra of a wide
  range
• of models
• We expect to be able to rule out or select
• models thanks to the next generation of CMB
• polarization-devoted experiments
• (EBEX, CMBpol, PolarBEar)

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CONCLUSIONS AND FURTHER THOUGHTS

• We can extract valuable information from
• the lensed CMB spectra
• The B-modes are the most faithful tracer
• of the dark energy behaviour at intermediate
• redshifts and can discriminate among models
• We have a computational machine allowing us
• to predict the lensed spectra of a wide
  range
• of models
• We expect to be able to rule out or select
• models thanks to the next generation of CMB
• polarization-devoted experiments
• (EBEX, CMBpol, PolarBEar)

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CONCLUSIONS AND FURTHER THOUGHTS

• We can extract valuable information from
• the lensed CMB spectra
• The B-modes are the most faithful tracer
• of the dark energy behaviour at intermediate
• redshifts and can discriminate among models
• We have a computational machine allowing us
• to predict the lensed spectra of a wide
  range
• of models
• We expect to be able to rule out or select
• models thanks to the next generation of CMB
• polarization-devoted experiments
• (EBEX, CMBpol, PolarBEar)

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CONCLUSIONS AND FURTHER THOUGHTS

• We can extract valuable information from
• the lensed CMB spectra
• The B-modes are the most faithful tracer
• of the dark energy behaviour at intermediate
• redshifts and can discriminate among models
• We have a computational machine allowing us
• to predict the lensed spectra of a wide
  range
• of models
• We expect to be able to rule out or select
• models thanks to the next generation of CMB
• polarization-devoted experiments
• (EBEX, CMBpol, PolarBEar)

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