1. Dark Energy L
The first Surprise in the era
of precision cosmology? f

2. L
Dark Energy Evidence f

3. L
Dark Energy Evidence f
Percival et al. MNRAS

4. WMAP+ACBAR+CBI+2dF+Lyman
Dark Energy Evidence
 4% f
WMAP+ACBAR+CBI+2dF+Lyman

5. Cosmological Constant Problem
G=8 T f

6. Cosmological Constant Problem
Geometry
G+ g=8 T +Vg f
Quantum Vacuum

7. Cosmological Constant Problem: ?
|-V|/M4Planck 10-120 f 4 V: ? M
Planck

8. ?? L
for Physics
Two ?
Why so small with respect to any particle physics scale ?
Why comparable to the cosmological matter density today f

9. L
Dark Energy Models
Trans Planckian: energy stored in perturbation modes
on super-horizon scales (Mersini et al., PRD , 2001)
Spacetime microstructure: self-adjusting spacetime capable
to absorbe vacuum energy (Padmanabhan, gr-qc/ )
Matter-Energy Transition: dark matter converts to dark energy at
low redshifts (astro-ph/ )
Brane worlds: brane tension (Shani & Sthanov astro-ph/ );
cyclic-ekpyrotic cosmic vacuum (Steinhardt &Tutok hep-th/ )
Quintessence: tracking scalar fields (Steinhardt, Wang & Zlatev,
PRD59, , 1999; Ratra & Peebles, Wetterich 1988)
Extended Quintessence: non-minimal coupling to Gravity (Uzan
Chiba, Perrotta, Baccigalupi, Matarrese, PRD61, , 2000
Coupled Quintessence: coupling with dark matter (Amendola,
Pietroni...) f

10. L
Quintessence Field
(t)+(t,x), U() f

11. L
Effects on the CMB
Projection
Integrated Sachs-Wolfe f

12. Quintessence & CMB: wf ,WfL f
Baccigalupi et al. 2002

13. Quintessence & CMB: wf ,WfL f

14. Quintessence & CMB: bispectrum Giovi et al. 2003, in preparationf

15. L f Quintessence & Large Scale Structure
Growth Factor, Transfer Function: Ma et al. 1998
Aperture Mass Statistics: Bartelmann, Perrotta, Baccigalupi 2002
Halo Concentration: Bartelmann et al. A&A 2002
N-body: Maccio’ et al. 2003

16. L f Extended Quintessence   Gravity   m c2eff,  1
dk2=4p k3(dr /r)k2
  Gravity
  m
c2eff,  1 f
Perrotta, Baccigalupi, Matarrese 2000, Perrotta & Baccigalupi 2002

17. L f Conclusions Discovery Concerning Vacuum Energy
Observable, Here and Now!
Probes: WMAPext+LSS, LSST, Planck, SNAP f

18. L
Dark Energy f