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Dark Energy Dark Energy The first Surprise in The first Surprise in the era the era of precision of precision cosmology?cosmology?
Dark Energy Evidence Dark Energy Evidence
Dark Energy Evidence Dark Energy Evidence
Percival et al. MNRAS Percival et al. MNRAS 327 1297 2001327 1297 2001
Dark Energy Evidence Dark Energy Evidence
WMAP+ACBAR+CBI+2dF+LymanWMAP+ACBAR+CBI+2dF+Lyman
4%4%
Cosmological Constant Problem Cosmological Constant Problem
GG=8=8 T T
Cosmological Constant Problem Cosmological Constant Problem
GG+ + gg=8=8 T T ++VVgg
Geometry Geometry
Quantum VacuumQuantum Vacuum
Cosmological Constant Problem Cosmological Constant Problem
||-V|/M-V|/M44PlanckPlanck 1010-120-120
::
V:V:
for Physics for Physics
Why so small Why so small with respect to with respect to
any particle any particle physics scalephysics scale
Why Why comparable comparable
to the to the cosmological cosmological
matter matter density todaydensity today
Two Two
Dark Energy Models Dark Energy Models • Trans PlanckianTrans Planckian: : energy stored in perturbation modes energy stored in perturbation modes on super-horizon scales (Mersini et al., PRD64 043508, 2001)on super-horizon scales (Mersini et al., PRD64 043508, 2001)• Spacetime microstructureSpacetime microstructure: self-adjusting spacetime capable : self-adjusting spacetime capable to absorbe vacuum energy (Padmanabhan, gr-qc/0204020)to absorbe vacuum energy (Padmanabhan, gr-qc/0204020)• Matter-Energy TransitionMatter-Energy Transition: dark matter converts to dark energy at: dark matter converts to dark energy atlow redshifts (astro-ph/0203383)low redshifts (astro-ph/0203383)• Brane worldsBrane worlds: brane tension (Shani & Sthanov astro-ph/0202346);: brane tension (Shani & Sthanov astro-ph/0202346);cyclic-ekpyrotic cosmic vacuum (Steinhardt &Tutok hep-th/0111098)cyclic-ekpyrotic cosmic vacuum (Steinhardt &Tutok hep-th/0111098)
• Quintessence: tracking scalar fields (Steinhardt, Wang & Zlatev, PRD59, 123504, 1999; Ratra & Peebles, Wetterich 1988)• Extended Quintessence: non-minimal coupling to Gravity (Uzan Chiba, Perrotta, Baccigalupi, Matarrese, PRD61, 023507, 2000• Coupled Quintessence: coupling with dark matter (Amendola, Pietroni...)
Quintessence Field Quintessence Field
(t)+(t)+(t,x), U((t,x), U())
Effects on the CMB Effects on the CMB • ProjectionProjection• Integrated Sachs-WolfeIntegrated Sachs-Wolfe
Quintessence & CMB: wQuintessence & CMB: w,,
Baccigalupi et al. 2002Baccigalupi et al. 2002
Quintessence & CMB: wQuintessence & CMB: w,,
Quintessence & CMB: bispectrum Quintessence & CMB: bispectrum
Giovi et al. 2003, in preparation Giovi et al. 2003, in preparation
Quintessence & Large Scale StructureQuintessence & Large Scale Structure
Aperture Mass Statistics: Bartelmann, Perrotta, Baccigalupi 2002 Aperture Mass Statistics: Bartelmann, Perrotta, Baccigalupi 2002
Halo Concentration: Bartelmann et al. A&A 2002 Halo Concentration: Bartelmann et al. A&A 2002
Growth Factor, Transfer Function: Ma et al. 1998Growth Factor, Transfer Function: Ma et al. 1998
N-body: Maccio’ et al. 2003 N-body: Maccio’ et al. 2003
Extended Quintessence Extended Quintessence kk
22=4=4 k k33(( / /))kk22
Perrotta, Baccigalupi, Matarrese 2000, Perrotta & Baccigalupi 2002 Perrotta, Baccigalupi, Matarrese 2000, Perrotta & Baccigalupi 2002
mm
cc22eff, eff, 11
GravityGravity
ConclusionsConclusions•DiscoveryDiscovery•Concerning Vacuum Concerning Vacuum EnergyEnergy
•Observable, Here and Now!Observable, Here and Now!•Probes: WMAPext+LSS, Probes: WMAPext+LSS, LSST, Planck, SNAPLSST, Planck, SNAP
Dark Energy Dark Energy