The HORIZON Quintessential
Simulations
A. Füzfa1,2,
J.-M. Alimi2, V. Boucher3, F. Roy2
1Chargé de recherches F.N.R.S.,
University of Namur, Belgium
2LUTh – Observatoire de Paris
3Center for Particle Physics Phenomenology (CP3), University of Louvain, Belgium
Cosmological Constant
Fine-tuning and coincidence! Frozen DE : =ct for all time Homogeneous DE No direct interactions with matter
(purely gravitational)
What is the nature of Dark Energy (DE)? Quintessence
Dynamical DE : Qvaries with time
Inhomogeneous DE : k,t≠0 Possible direct interactions with
matter (not purely gravitational):
• DE-DM couplings (see PSC talk)
• DE-Baryons couplings
• Violation of the equivalence principle!
Casimir effect(Vacuum
Fluctuations)
Negative pressures!
Evacuum↑
Evacuum
Evacuum↑↑↑
Cosmic expansion produces more vacuum energy
Cosmic acceleration!
V
t
)(ta
Theoretical approaches to DE (quintessence, scalar-tensor gravity, …)
→ a(t),H(t), (t), G(t), D+(a) …
↓
Constraints from recent cosmic expansion
(Hubble diagrams of SNe Ia)→ m,Q
↓
Constraints from CMB angular fluctuations → b,CDM, 8lin
↓
Linear Matter Power Spectrum at z=0
and Linear growing modes D+(a)
→ initial conditions at zstart
↓
N-body simulations (CDM only, here) with corresponding H(a)
↓
Observational constraints :
weak-lensing, baryon acoustic oscillation, …
Dark energy and structure formation
Cosmological constant CDM
Quintessence scenari:
Ratra-Peebles potential (SUSY breaking, backreactions, …) RPCDM
Sugra potential (radiative correction of RPCDM at E~mPl) SUCDM
A) Considered theoretical models
2
3
4m
G
a
a
3 if 0 QQpa
QQm p
G
a
a3
3
4
VQ 2
² VpQ
2
²
4
V
²4exp4
GV
03
d
dV
a
a
Determination of m and ,Q) from SNLS 1st year data set
Degeneracies of the models (≈²=116 for 115 data) CDM vs QCDM’s : frozen vs dynamical DE RPCDM vs SUCDM: LSS tests of varying w(z)
B) Constraints from Hubble diagrams
SNe Iaredshift
range z<1.1
astart
CMB
Hubble Parameter Equation of State
Modification of CAMB code (in collaboration with V. Boucher, CP3): Cosmic expansion with quintessence (zeroth order) first order perturbations of the quintessence fluid (large-scales inhomogeneities) minimal-coupling
Results:
C) Constraints from CMB anisotropies
Angular Power Spectrum Linear Matter Power Spectrum
DE Clusterization
Different b/CDM
Different 8
D) Cosmological parameters table
Models/
ParametersCDM RPCDM SUCDM
m 0.24 0.2 0.18
b 0.042 0.041 0.042
8lin 0.74 0.58 0.45
/ =5 eV , =0.5 =3x106 GeV , =6
(SNLS data) 116.76 116.58 116.66
WMAP3)
(log-likelihood)
-486.25 -491.23 -502.35
H0=73 km/s/Mpc ; ,Q=1-m
astart=0.0403 ; ns=0.951
E) N-body quintessential simulations
Quintessence and cosmological constant DE models are almost equivalent to explain CMB and SNe Ia
LSS can settle the DE debate? New constraints on DE from LSS Criteria for detecting w(z) at z>>1 Predictions on LSS from alternatives to
Horizon Quintessential Simulations (CDM, RPCDM, SUCDM): L=500h-1Mpc ; Npart=Ncells=10243 ; CDM only (Particle-Mesh code) 65 snapshots (26+1) between as=0.04 and a0=1 3x1.6 Tb data 3 x 3000 h on Zahir (IDRIS) with 32 Procs, 3.7Gb RAM/Procs (300 time steps) Present storage: gaya.idris.fr => /fuzfa At disposal for the collaboration at horizon.obspm.fr:/storage
The results so far…
CDM@z=0
RPCDM@z=0
SUCDM@z=0
CDM@z=0
RPCDM@z=0
SUCDM@z=0
Tools developped: DarkCosmos (homogeneous cosmological models with quintessence ; adequacy
with Hubble diagrams of type Ia SNe and linear growing modes) CAMB+Q : CMB code with zero and first order behavior of quintessence Mpgrafic-Q : initial conditions from a CAMB generated power spectrum PM+Q : N-body DM only Particle-Mesh code with quintessence (normalization
and cosmic expansion)
Interesting analysis of quintessential simulations (HORIZON Collaboration): Effect of slope of power spectrum at large-scales (DE clusterization): 3D skeleton Baryon wiggles, correlation function (baryon acoustic oscillation) and non-linear
8
DM Clusters properties (mass function, velocity distribution, …) Semi-analytical approaches to populate with virtual objects Quintessential simulations for weak-lensing
Toward new constraints on DE from LSS?
Conclusions