CMB but also Dark Energy

Carlo Baccigalupi, Francesca Perrotta

Work Fun

• Theory, Extended Quintessence, funny effects of Gravity and Dark Energy Coupling

• Phenomenology, CMB spectrum and bispectrum, B modes, acceleration and structure formation

“Quintessence’’ models of DE

A classical, minimally-coupled scalar field evolves in a potential Vwhile its energy density and pressure combine to produce a negative equation of state w=p/

• Fine-tuning problem: in analogy with the need to tune initial values of to get the observed energy density and equation of state;

• “Coincidence’’ problem: why m ~just today ?

Search for ATTRACTOR SOLUTIONS (“tracking fields”)Search for ATTRACTOR SOLUTIONS (“tracking fields”)

Perrotta F., Matarrese S., Baccigalupi C., Phys. Rev. D 61 (2000) 023507

Extended Quintessence

R-boost Klein-Gordon equation in EQ:

Since R diverges as a-3 as a 0 (if non-relativistic species arepresent) , an “effective” potential is generated in the KG equation, boosting the dynamics of at early times. EQ admits tracking trajectories AND they are good trackers(large basin of attraction)

r m

(mc)

R-boost

(mc)

(TEQ)

(TEQ)

Approaching without fine-tuning

Matarrese S., Baccigalupi C., Perrotta F., to appear on Phys. Rev. D

W0= -0.999, TEQ for different initial K,V

W0= -0.999 for minimally coupled Q and different initial values of

Linear and non-linear perturbations

• Clustering properties: scalar field perturbations may interact with matter perturbations in EQ models.

• Weak lensing : variations of G induce corrections in distance calculations; perturbations gain a new d.o.f., the anisotropic stress

• CMB effects (ISW, projection, lensing, bispectrum)• Effects on LSS and structure formation • Backreaction of EQ perturbations on the background metric? (difference between Einstein

tensor formed from the averaged metric and the averaged value of the Einstein tensor)

• Search for purely gravitational explanation of cosmic acceleration (EQ without

potential)

Perrotta F., Baccigalupi 2002; Perrotta et al. 2003

Acquaviva V., Baccigalupi C., Perrotta F., 2004

Dark Energy and CMB

DEfast

• A cmbfast 4.0 based code for dark energy cosmologies

• Scalar field dark energy models in ordinary or scalar-tensor cosmologies

• Effective dark energy models (Linder 2003): w=w0+(1-a)(w1-w0)

• Used for ~ 10 papers

ISW and Projection

CMB Cls and Dark Energy

• ISW killed by Cosmic Variance

• Projection degenerated with s, H0, K, … but still the basic effect on which CMB constraints on dark energy are based so far

• Projection unable to probe w(z), two redshift integrals wash that out

CMB Cls and Dark Energy

Phys.Rev.D65, 063520, 2002

CMB Cls and Dark Energy

Phys.Rev.D65, 063520, 2002

Efstathiou Tensor Degenera

cy, 2003

BBllm m

l`l`m`m`

l``l``m``m``=a=almlm a al`m`l`m` a al``m``l``m``

aalmlm==ss ( ( )Y )Ylmlm(( )d )d

BBl l`l``l l`l``==m m` m``m m` m`` ( (mmllm`m`

l`l`m``m``

l``l``) a) almlm a al`m`l`m` a al``m``l``m``

ll

l`l`l``l``

(( ) ) ´́ T(T( )/T )/T

Beyond Cls: CMB bispectrum

< B< Bllm m

l`l`m`m`

l``l``m`` m`` >=0>=0

< B< Bllm m

l`l`m`m`

l``l``m`` m`` >> 0 0

Weak lensing and CMB bispectrum

CMB bispectrum and w1

w1=-0.3

w0=w1=-0.9

Beyond Cls: B modes in CMB Polarisation

Dark Energy and Structure Formation

DE, lin. Pert., Carlo Baccigalupi

DE theory & models, Francesca Perrotta

Trieste

DE, lin. Pert., Carlo Baccigalupi

DE theory & models, Francesca Perrotta

Lensing, Str.Form., Matthias Bartelmann

Lensing, Massimo MeneghettiHeidelberg

DE, lin. Pert., Carlo Baccigalupi

DE theory & models, Francesca Perrotta

Lensing, Str.Form., Matthias Bartelmann

Lensing, Massimo Meneghetti

Str. Form., Lauro Moscardini

N-body, Klaus Dolag

Str. Form., Giuseppe Tormen Bologna

Padua

Garching

Cluster Concentration

Astron.Astrophys. 416, 853, 2004

Simulating Arcs

astro-ph/0405070

More…

• CMB bispectrum, how much does it helps?

• Weak lensing and B modes on large scales in dark energy cosmologies

• Non-linear structures and CMB lensing…

• Bring the news on CMB and SNIa together, a Beyond Einstein proposal in preparation (Linder & Baccigalupi)