Comments and Questions about the Dark Universe

1
Comments and Questions about the Dark Universe
Charling TAO CPPM Université de la
Méditerranée Tsinghua 2005 tao_at_cppm.in2p3.fr
2
Outline of the presentation
1) Brief introduction on SuperNovae 2) Present
SNIa data 3) Determination of cosmological
parameters a concordant or a convergent
Universe? 4)  Experimentalist  point of view
SNIa  2 s   effect? Perhaps too early to speak
about new physics !?! 5) How can SN results be
improved? 6) Need for more theoretical work 7)
What about Cosmology tests in the lab?
3
Supernovae

• Exploding stars ? Brightest objects in Universe
• Can sometimes be seen by eye rare! 8 recorded
  in 2000 years

• Historical (super) novae
• Chinese records 185, 369, 1006 (arabo-persian
  also), 1054, 1181.

• 1572 (Tycho Brahe), 1604 (Kepler)
• visible during the day

• 1987A LMC UV, X, radio, visible, neutrinos
  !

4
Historical SN Classification
SN Spectra

• Type I absence of hydrogen
• Type Ia presence of ionised Silicium (SiII)
• Type Ib absence of silicium, presence of helium
• Type Ic absence of silicium and helium
• Type II Presence of hydrogen Ha and Hb
• Type II normal domination of hydrogen,
  presence of helium. IIL (linear) or IIP (plateau)
  according to Light curves
• Type IIb Dominating presence of helium
• Peculiar types

5
Supernovae explosions
Red giant
White dwarf
Chandrasekhar mass 1.4 MO
Core Collapse SN
SNIa 2 stars (a white dwarf )
6
Interest of SN study

• Physics of galaxies ISM heavy elements and
  star formation
• Physics of stars explosion at end of star life
• Particle Physics neutrinos properties
• Philosophy We are supernovae dust

• Cosmology distance indicators (SNIa)

7
Equations of evolution of the Universe
General Relativity Matter and energy impact the
geometry of the Universe and its evolution. gt
Equation of movement Friedmann equation
.
.
Mmatter Rradiation Xexotic L cosmological
constant kcurvature

• Equation of state wp/? (w-1 for ?) describes
  the change in the Hubble parameter and impacts
• angular distance - diameter
• structures growth rates
• Large Scale Structures (LSS) power spectra
• Weak Lensing (WL) power spectra
• . (Ma, Caldwell, Bode Wang ,
  1999)

8
Measuring distances
Cosmology additional a(t) scale factor
D(t) a(t) D(t0)
a(t) a0(1 H0t -1/2 q0 (H0t)2 )
SN 1996
H0 Hubble parameter measures the expansion
rate of the Universe H0 (a/a)0 100 h
km/s/Mpc , h 0.72 /- 0.05 (?) q0
deceleration parameter A Universe with only
matter is expected to decelerate
.
.
9
The Hubble diagram with SNIa
Absolute magnitude
m(z) M 5 log (DL(z,WM,WL))-5log(H0)25
10
The classical SN observation method

• A 3 steps method
• Discovery subtraction from a reference image.
• Supernova type identification and redshift
  measurement
• Photometric follow-up

light curve
spectrum
?Final analysis Hubble diagram.
11
SN Ia are not exact standard candles!
The light of SNIa explosions can be followed up
for several weeks with telescopes
12
Different standardisation methods
Standardisation to Dm 0.2
Before mB
After, eg, stretch correction mBcor mB a
(s-1)
Different standardisation methods stretch
(SCP), MLC2k2 (HiZ), Dm15, ...
13
The  classical  method
galaxy
magnitude
z(redshift)
Images
Hubble
identification.
Spectra
Ia
14
Fit cosmological parameters

• From Hubble diagram, fit models
• Determine dark energy parameters WL, or (WX, w,
  w) and matter density WM

mag
z
1
15
SNIa
SURPRISE Indication for negative deceleration
parameter q0 Acceleration!!!

• W r(t)/rc(t) WM WL
• 1- Wk
• ?L L/3H02
• q0 1/2 WM- WL lt 0

z
16
2) SN Ia the present status a selection by
Riess et al, astro-ph 0402512
16 new SN Ia with HST (GOOD ACS Treasury
program) 6 / 7 existing with z gt1.25

• Compilation (Tonry et al. 2003) 172 with
  changes from
• Knop et al, 2003, SCP 11 new 0.4 lt z lt
  0.85
• reanalysis of 1999, Perlmutter et al.
  
• 15 / original 42 excluded/inaccurate colour
  measurements and uncertain classification
• 6 /42 and 5/11 fail  strict  SNIA 
  sample cut
• Barris et al, 2003, HZT 22 new varying
  degrees of completeness on
  photometry and spectroscopy records
• Blakesly et al, 2003 2 with ACS on
  HST

• Low z 0.01 lt z lt 0.15
• Calan-Tololo (Hamuy et al., 1996) 29
• CfA I (Riess et al. 1999) 22
• CfA II (Jha et al, 2004b) 44

17
SN Ia 2004 Riess et al, astro-ph 0402512
183 SNIa selected ? Gold set of 157 SN Ia
WM0.29 WL0.71 Prior Flat Universe
But also non concordant models
Fits well the concordance model c2 178 /157
SNe Ia
18
Riess et al. (fit quality)
19
Determination of Cosmological parameters
wp/r
w w0w z
Riess et al, astro-ph 0402512
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Some Phenomenological work on SNIa
Virey, Ealet, Tao, Tilquin, Bonissent, Fouchez,
Taxil astro-ph/0407452
Simulation and analysis tool Kosmoshow
developed in IDL by André Tilquin (CPPM)
marwww.in2p3.fr/renoir/Kosmoshow.html
21
Equations of evolution of the Universe
Matter and energy impact the geometry of the
Universe and its evolution. gt Equation of
movement Friedmann equation
Mmatter Rradiation Xexotic L cosmological
constant kcurvature

• Equation of state wp/? (w-1 for ?) describes
  the change in the Hubble parameter and impacts
• angular distance - diameter
• structures growth rates
• Large Scale Structures (LSS) power spectra
• Weak Lensing (WL) power spectra
• . (Ma, Caldwell,
  Bode Wang , 1999)

22
Example of possible bias large w1

• Suggestion Maor et al...
• w0F-0.7
• w1F 0.8
• WM 0.3

Beware of fitting method !!!
Bias from the time evolution of the equation of
state astro-ph/0403285, Virey et
al. Quantitative analysis of the bias on the
cosmological parameters from the fitting
procedure, ie, assuming a constant w, when it is
not!
With present statistics, can be
ignored Not the case with larger samples!
23
Riess 2004, gold sample
Fit with no prior
LCDM concordant model
24
Riess et al. SNIa data results for different
fits
(157 SN Ia  gold sample   Riess et al.,
astro-ph/040251)
w p/r w0 w1z
Results Riess et al

• SN data seem to prefer larger Wm
• Instability of results with fits
• Errors on w1 are small only if Wm 0.3

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3) Reanalysis of Riess et al. SNIa data
A concordant or a converging Universe ?
Virey et al., astro-ph 0407452

• With prior WM 0.27 /- 0.04, always LCDM (ie
  w-1) reconstructed, even with different
  assumptions in simulations , eg, WM 0.48 ,
  w/-1
• ? LCDM convergent model !?!

• Without flat prior, NO strong constraints from
  SNIa
• Prior Flat Universe , but no prior on WM
• SNIa ? WM 0.48 preferred value

Is WM 0.27 /- 0.04 ???
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Many determinations of WM
Riess et al., astro-ph/0402512 SN ?
WM 0.27 /- 0.04
X
Freedman and Turner, Rev.Mod.Phys.
(astro-ph/0308418) WM 0.29 /- 0.04

• WMAP CMB
• Bennett et al., 2003 ApJS, 148, 1 with h0.71
  /- 0.05 ? 0.27 /- 0.04
• Spergel et al. 2003 ApJS, 148, 175
• CMB alone WM h2 0.14 /- 0.02
  ? 0.27 /- 0.10
• CMB 2dFGRS WMh2 0.134 /- 0.006 with h0.72
  /- 0.05 ?0.26 /- 0.04

• 2dFGRS Hawkins et al., astro-ph/0212375 MNRAS,
  only bias
• Tegmark et al. astro-ph/0310725 3D power
  spectrum of galaxies from SDSS
• astro-ph/0310723
  Cosmological parameters from SDSS and WMAP,
• 
  Clusters, Weak Lensing, etc.

N. Bahcall et al. Comparison M/L
data/simulation WM 0.16 /-0.05 S.
Vauclair et al. XMM X-ray clusters
WM gt 0.85
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What is Cosmic Microwave Background?

• Penzias et Wilson (1965) Giant Bell Lab Radio
  Antenna for detection of intergalactic radio
  emission
• Noise excess in all directions (7,5 cm l)
  Black body radiation at 3.7 /- 1 o K
  Plancks Law

• Cosmological Interpretation Dicke, Wilkinson
  Peebles, Roll
• Big Bang ? Relic radiation
• (Gamow (1948) et Alpher et Herman (1950))

Black Body radiation curve COBE (1992) from 0.5
to 5mm T 2.728 /- 0.002 K (T 2.72528 /-
0.00065 K)
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Anisotropies
Simulation de galaxies
Ned Wright Cosmology tutorial

• Anisotropies can be generated by many effects
• acoustic, Doppler, gravitational redshift,
  photons scattering,
• Complex phenomena ?
• Initial surprise Weakness of the observed
  effect

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A very isotropic CMB
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First measured anisotropies
dipole radiation from the Milky Way (1969)
Milky Way horizontal in the centre
v/c T0
-v/c T0
COBE (1992) v 371 /- 0.5 km/s
Temperature fluctuations 1 / 1000
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Brief History
Photons hot enough to ionize H Compton
Scattering couples g to e, and baryons?
Dynamical system Baryon-photon Fluid g
pressure resists the fluid gravitational
compression ? acoustic oscillations
Recombination Neutral hydrogen formation and g
last scattering Hot (compression) and cold
regions ? present traces g undergo also a
gravitational redshift from the potentials at
last scattering.
W.Hu
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First measurements of CMB anisotropies
Prédictions de Sachs et Wolfe (1967) autour de
10-3, non observées
COBE (1990) around 10-5 30 mK
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Temperature fluctuations

• Decomposition in spherical harmonics
• T (2.725/-0.01)K (3.358/-0.02)mK
  cosq S lgt1,m alm Ylm
• Temperature is real ? alm alm
• Term in l ? variation on angular scale Dq p/ l
• angle-multipole connexion due to
• Ylm has l-m zeros for 1lt cosqlt 1
• Re(Ylm) has m zeros for 0ltFlt2p

Solar system peculiar velocity
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Angular power spectrum
(Adapted Lineweaver, 1998)
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Foreground contaminations
Component separation by measurements in different
frequencies Theoretical Extrapolation to CMB
region
Between 100 and 200 GHz !
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WMAP
Launched june 2001 in space
37
Wilkinson Microwave Anisotropy Probe
David T. Wilkinson 1935-2002
WMAP model
WMAP science team
http//map.gsfc.nasa.gov/m_mm/pub_papers/firstyear
.html
2003
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WMAP results
Curve best fit LCDM
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WMAP cosmological parameters (Table I)

• LCDM, ie, flat Universe and equation of state w
  p/r cte ( -1)
• Measures Wm h2 and Wb h2 ? fb Wb/Wm 0.17
  /-0.02

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!!!! WMAP note !!!!! Strong degeneracy
in Spergel et al., 2003 ApJS, 148, 175

• WM 0.47, w-0.5 and h0.57 gt identical power
  spectrum
• solution excluded for 3 reasons
• 1) h0.57 2s from HST
• 2) worse fit SNIa results not true
• 3) poor fit 2dFGRS galaxy power spectrum
  surveys

Blanchard et al. controversial
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2dfGRS use of CMB prior
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SDSS galaxies power spectrum
Tegmark et al. astro-ph/0310723
WM0.4 h0.72 0.5 h0.56
Baryon fraction

• Indication for
• Systematics
• not cste w?
• ?

WMAP LCDM
h WM
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Precision cosmology? Not Just Yet
Bridle et al. Science 299(2003) 1532astro-ph
0303180
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SNIa fits with weak priorsWM 0.30 /- 0.2
Virey, Ealet, Tao, Tilquin, Bonissent, Fouchez,
Taxil astro-ph/0407452

• no prior on WM (flat Universe), eg, WM lt
  0.60
• other solutions still possible even
  decelerating Universes

Quintessence
Phantom
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SN data interpretation needs more precise
determinations of WMor combination with other
data
Tools existing for each observation eg, CMB
CMBFAST, etc SNIa Kosmoshow, Y. Wang, Weak
Lensing, Clusters, Extraction of cosmological
parameters using  priors on other data
Tools needed for combined analysis Attempts
Tegmark Wang, Corasaniti et al., Padmanabhan et
al., For different models, eg, with variable w
46
Combined SN, CMB, WL constraints on equation of
state
Upadhye , Ishak and Steinhardt, astro-ph 0411803
Future constraints
SNAP/JDEM Planck
47
Weak gravitational Lensing
Background image distorsions by foreground matter

Without lensing lensing
effect
48
Weak Lensing
Distortion Matrix

• Direct measurement of mass distribution in the
  universe,
• Other methods measure light distributions

49
Weak Lensing principle
Distortion Matrix Convergence Shear Critic
al surface density
Weak lensing regime ? ltlt 1 (linear
approximation) ?Measure shear ? and solve for
projected mass ?
50
Dark Energy and Weak Lensing
w is measurable by WL power spectrum But
degeneracy between w, ?M ,?8 and ?
Hui 1999, Benabed Bernardeau 2001, Huterer
2001, Hu 2000, Munshi Wang 2002
51
4) A closer look at SN measurements
52
Spectroscopy when possible

• SN Ia Identification
• Spectrum structure
• Redshift z measurement
• From position of identified lines from spectra SN
  and/or underlying galaxy

53
Supernovæ identification
Simulation of a SN Ia spectrum at z?0,5

• With Spectra
• Main stamp of the SNe Ia Si II at 6150 Å
  (supernova rest frame)
• Hardly observable beyond z gt 0.4-0.5.
• Otherwise, search for features in the range
  3500-5500 Å (supernova rest frame)
• Ca HK, SiII at 4100 Å, SII,

Ca HK SiII 4100
observed at VLT (SNLS)
54
SNIa sample contamination
Need strict selection criteria But reduces
statistics !
55
Atmospheric transmission (ground)
Reduced efficiency Not homogeneous
filters Redshift dependent !!!
Reduction of transmission in visible Absorption
water O2 reduce visibility in IR
56
Atmospheric emission
57
Spectroscopy Need to subtract galaxy
58
Systematic effects
Extragalactic environment
local
Supernova environment
reduction/correlations SNIa contamination Selectio
n bias Inter calibration filters
Normal Dust absorption Lensing Grey Dust SN
evolution
59
Systematic effects
Observational problems Standardisation
method Light curve fitting Heterogeneity of SN
data SNIa identification Subtractions Calibration
s Atmospheric corrections K-corrections Selection
bias

• Astrophysical problems
• SN evolution
• Internal extinction not negligible in spiral
  galaxies
• Corrections for peculiar velocity effects
• Grey dust
• Lensing
• Rowan-Robinson astro-ph/021034
• Perlmutter Schmidt 0303428

60
SN Ia photometry needs many corrections
mag
light curve
- Atmospheric observational corrections - Light
Curves measured in SN reference frame ? in local
reference frame - Galactic extinction
correction NOT ALL VERY PRECISE OR WELL
UNDERSTOOD!, YET!
61
Precision on the magnitude at the maximum
Stretch uncorrected
Stretch corrected
Precision on the magnitude dominated by intrinsic
dispersion dmint ? 0.15
62
Knop et al (2003) light curves
63
Redshift calibration

• Spectrum is dilated by (1z)
• Flux is integrated in a filter for a photometric
  point, but filter responses are not flat.
• Sometimes, need different filters
• Corrections for differences (l shift)
• ? Systematic effects

64
Astrophysical effects

• SN evolution
• Internal extinction not negligible in spiral
  galaxies
• Increase of the fraction of star-forming systems
  with z ? average host galaxy extinction should be
  higher?
• DeVaucouleurs prescription (1976)
• Corrections for peculiar velocity effects
• Grey dust
• Lensing

65
Dependence on SN Environment
Blue have a lower metallicity - Can be seen
further
66
Supernovae evolution
Peak magnitude can change Explosion changes with
environment Difference of chemical elements
around SN Depends on galaxy morphology, age,
type,

• Sullivan et al (2002) SCP
• SNIa host galaxy morphological classification
• Not a large effect, but statistics are still low

67
Extinction and Dust

• Extinction by dust from Our or SN galaxy

• Correction factor to the magnitude
• A R E(B-V)
• Measurements in many filters
• Select minimal dust regions ?

Before extinction

• Rv3.1 /- 0.3 for our Galaxy
• Very large correction
• Effective SNIa Rv 2 ?

After correction

• Grey dust not well known, intergalactic,?

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A strong limit on grey dust?
Peerels, Tells, Petric, Helfand (2003)

• A 24.7 hr Chandra exposure of QSO 1508-5714
  z4.3 shows no dust scattering halo
• Upper limit on mass density of large grained
  (gt1mm) intergalactic dust Wdust lt 2 10-6

69
Dust and evolution ?
Sensitivity to dark energy decrease for z gt 0.6
Dust Homogeneous gray intergalactic
dust? Galactic dust responsible for extinction?

• Evolution shift due to progenitor
• mass?
• metallicity?
• Ni distribution?
• Other effects?

Is there a region of deceleration? Need
to go to zgt 1
70
Gravitational Lensing in a Clumpy Universe
Weak lensing approximation Power spectrum of
mass density in a relatively smooth universe
71
Some estimates of Systematics
72
Systematic differences between standardisation
methods (Riess et al.)
73
Constraints on cosmological parameters
Dm 0.2 - 0.3 effect!
74
Systematic errors on magnitude
3 fit with no prior
Use Kosmoshow an IDL program by A. Tilquin!
marwww.in2p3.fr/renoir/kosmoshow.html
20 calibration error on intermediate fluxes
gives no cosmological constant
75
Riess gold sample sensitivity
Kosmoshow, A. Tilquin
76
A Dm0.27 shift of low z data
A  2 s  effect!
Use Kosmoshow by A. Tilquin!
Shift z lt0.15 data by Dm 0.27 ? Wm 0.43 /-0.2
and WL 0 /-0.34

• No need for L
• But Universe is not flat!

77
5) How can SN results be improved?

• Data still dominated by statistical errors
• ? Need more data ? Better study of systematic
  effects
• ground space

• Study of w(z)
• ? Need large sample of low z data for
  systematics
• ? Need higher z data ? Need low z UV SN sample
• ? need to
  go to space atmosphere

• Need better quality data
• Reduce atmospheric fluctuations
• Gain statistics by spectro most SN
  

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Requirements for SNIa search

• Ideally
• Many SN for a negligible statistical error and
  study
• of systematic conditions. ? wide field
• Detect deceleration zone (zgt1) ? measure in IR
• (or have large local UV sample for SNIa
  identification)
• Control the correction precision for SNIa
• standardisation (environment and measurement
  corrections)
• Control non corrected systematic effects to the
  same level
• ? Very precise light curves and spectra to
  determine
• the explosion parameters, at all distances.

Best in space!
79
How to constrain SNIa systematic effects and get
precise measurements?

• Ideally in space SNAP/JDEM, DUNE
• Problem gt 2014

• In the meantime More statistics from as
  homogeneous samples as possible
• CFHTLS and ESSENCE Nearby

80
Low z activities

• Nearby SuperNova Factory
• 300 SNIa (2004-) snfactory.lbl.gov
• Physics of SNIa explosions
• Supernovae at CfA (ongoing)
• Expect 100
• www.harvard.edu/cfa/oir/Research/supernova.html

81
Low z Nearby Supernova Factory (2004-)

• Goals
• 100/yr 0.03ltzlt0.08
• 10 spectro-photometric between 14d and 40d
• Spectra 320-1000 nm
• Tools
• Discovery Two cameras (one wide field) 1.2 m
  ground based telescopes NEAT
• Lightcurve follow-up with YALO
• Photo-spectro follow-up with Field Integral
  Spectrometre (SNIFS) for ground based 2.2m
  telescope (Hawaii)

• Collaboration
• France CRAL,IPNL, LPNHE
• US LBNL, U.Chicago

82
Intermediate z (2003-2014)

• ESSENCE at CTIO www.ctio.noao.edu/wproject/sne
• 50 SN Ia/year
• SNLS with MEGACAM of CFHT Legacy Survey
  /snls.in2p3.fr/
• MEGACAM working since march 2003
• Foreseen 700 SNIa z lt 1.

83
The CFHT Legacy Survey Supernovæ Program
84
SNLS the instruments
A wide field camera (1 square degree, MEGACAM
0.35 Giga pixels) on 3.6 m CFHT (Hawaii)
telescope
85
SNLS expected results
WM contraint
WM contraint
SN only DWL0.1 and Dw0.2 limited to zlt0.95
(atmosphere)
86
Comparison with present measurements
Only statistical errors
68
Flat
87
Joint Dark Energy Constraints
Current efforts focus on the complementarity of
supernova and weak-lensing measurements of the
dark-energy parameters.
CFHTLS Wide Field Weak Lensing - an ongoing
program
88
Joint Dark Energy Constraints from SNAP
Dark Energy Constraints from Cross-Correlation
Cosmography Bernstein Jain 2004 Constraints
from Power Spectrum and Bispectrum Takada Jain
2003
NOTE Lensing constraints do not contain
systematic error estimates.
(wwa/2 at z1)
89
SNAP /JDEM a dedicated satellite
Large statistics 2000 Sne Ia/yr redshift to
zlt1.7, Minimal selection Ia identification
2m wide field telescope
90
SNAP survey
Hubble Deep Field
Observe repeatedly same sky area
Wide field !!

• Surveys
• Supernova Survey
• 2X7,5 sq. deg.
• 2X16 months
• Rlt30.4 (9 bands)
• Weak Lensing Survey
• 300 sq. deg.
• 0.5-1 year
• Rlt28.8 (9 bands)

Supernova Survey
Weak Lensing Survey
Each field is observed 4 days All images are
accumulated
91
SNAP Expectations
Résultats-diagramme de Hubble
92
SNAP expected results
Weak Lensing CMB
93
6) Testing the Dark Energy Paradigm
Where is progress to come from?
Phenomenology
Observations
Theory !
94
The cosmological constant L a problem for field
theorists
X

• General Relativity ? L scale
• Cosmological measurements
• rLobs (10-12 GeV)4 2 x 10-17 J/cm3
• Particle physics ? L vacuum energy
• vacuum perfect fluid p -rL -
  L/(8pG)
• rLEW (200 GeV)4 3 x 1040 J/cm3
• rLQCD (0.3 GeV)4 1.6 x 1029 J/cm3
• rLPl (1018 GeV)4 2 x 10103 J/cm3

1 GeV 1.6 10-10 Joules
X
Difference 120 orders of magnitude !
Coincidence with Neutrino scale?
rLobs (10-12 GeV)4 (meV)4
95
Quintessence

• Introduced to solve the cosmological constant
  problem
• Wetterich, Ratra Peebles (1988),
• Exponential scalar field
•  Berk!!!  (field theorist),  Unnatural 
  (tHooft)
• Many varieties of the model
• does not couple with gravity (in simplest
  models)
• Predictions for SNIA, CMB,
• Different from simple inflation models

96
A Quantum Gravity effect?

• - What is the average density of the Universe
  that is measured by cosmologists?
• If it has to do with Quantum Gravity Vacuum
  fluctuations, need to unify General Relativity
  and Gravity!

Loop Quantum Gravity Ashtekar, Smolin, Rovelli,
etc
Spinor Gravity Wetterich
SuperStrings ..
MOND Milgrom, Beckenstein
Extensions to GR Moffat
Negative energies Henry-Couannier
QFT in curved spacetime
97
Why measure precisely cosmological parameters?

• Check that the Universe is flat to a better
  precision (Planck Surveyor)
• If Wtot 1 Distinguish between inflationary
  models
• Alternative models predict deviations from scale
  invariance
• Amount of tensor perturbations to large scale CMB
  anisotropies small or comparable to scalar
  perturbations?
• Determination of neutrino masses to around 0.1
  eV?
• Massive neutrinos slow down structure growth in
  small scales and modify the amplitude and shape
  of the matter and CMB power spectrum
• Check that there is really a Dark Energy
  component. Is Dark Energy a cosmological
  constant or something more complex and dynamical
  ?
• Dependence on the equation of state w
• (SNAP/JDEM, DUNE
  Planck Surveyor ???)

98
Modern Cosmology Dark Matter, Dark Energy
Universe by Aristotle
Modern epicycles?
Need for a conceptual Revolution?
99
A mysterious and interesting Universe
Definition Wr/rc (rc10-29 g/cm3)
Ordinary Matter 4
100
Testing the Dark Energy Paradigm
Where is progress to come from?
Phenomenology
Observations
Theory !
What about testing Physics in the Lab?
101
Zero point energy and vacuum fluctuations
Plancks second theory of black body radiation
Average energy of collection of oscillators

• Zero point energy term
• Experimental effects
• X-ray scattering in solids
• Lamb shift understanding between s and p levels
  in hydrogen
• Casimir effect
• Origin of van der Waals forces
• Interpretation of Aharonov-Bohm effect
• Compton scattering

Well known black-body spectrum
Look eg, _at_ Spectra of noise in electrical
circuits
102
Josephson junctions evidence for ZPE term
From Koch et al., Phys. Rev. B, 26, 74, (1982).
103
Dark energy cutoff?
Beck and Mackey astro-ph/0406504
104
TeraHz Josephson junctions ?
From Koch et al., Phys. Rev. B, 26, 74,(1982).
Possible cutoff?
Interesting lab experiments ? A factor 3 to gain
from 1982 experiment
Exist in LERMA
105
DE Contributions cannot be determined from noise
measurements
Jetzer Straumann, astro-ph 0411034
The absolute value of the ZPE of a quantum
mechanical system has no meaning when
gravitational coupling is ignored.
All that is measurable are changes of the ZPE
under variations of system parameters or of
external changes
ZPE / Gravity vacuum fluctuations