1. The HORIZON Quintessential Simulations A.Füzfa 1,2, J.-M. Alimi 2, V. Boucher 3, F. Roy 2 1 Chargé de recherches F.N.R.S., University of Namur, Belgium 2 LUTh – Observatoire de Paris 3 Center for Particle Physics Phenomenology (CP3), University of Louvain, Belgium

2.  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 :  Q varies 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! E vacuum ↑ E vacuum E vacuum ↑↑↑ Cosmic expansion produces more vacuum energy Cosmic acceleration!

3. 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,  8 lin ↓ Linear Matter Power Spectrum at z=0 and Linear growing modes D + (a) → initial conditions at z start ↓ N-body simulations (CDM only, here) with corresponding H(a) ↓ Observational constraints : weak-lensing, baryon acoustic oscillation, … Dark energy and structure formation

4.  Cosmological constant  CDM  Quintessence scenari:  Ratra-Peebles potential (SUSY breaking, backreactions, …) RPCDM  Sugra potential (radiative correction of RPCDM at E~m Pl ) SUCDM A) Considered theoretical models

5.  Determination of  m and  ,Q) from SNLS 1 st 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 Ia redshift range z<1.1 a start CMB Hubble Parameter Equation of State

6.  Modification of CAMB code (in collaboration with V. Boucher, CP3):  Cosmic expansion with quintessence (zero th order)  first order perturbations of the quintessence fluid (large-scales inhomogeneities)  minimal-coupling  Results: C) Constraints from CMB anisotropies Angular Power SpectrumLinear Matter Power Spectrum DE Clusterization Different  b /  CDM Different  8

7. D) Cosmological parameters table Models / Parameters  CDM RPCDMSUCDM mm 0.240.20.18 bb 0.0420.0410.042  8 lin 0.740.580.45  / =5 eV,  =0.5 =3x10 6 GeV,  =6   (SNLS data) 116.76116.58116.66    WMAP3) (log-likelihood) - 486.25 - 491.23 - 502.35 H 0 =73 km/s/Mpc ;  ,Q =1-  m a start =0.0403 ; n s =0.951

8. 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 -1 Mpc ; N part =N cells =1024 3 ; CDM only (Particle-Mesh code)  65 snapshots (2 6 +1) between a s =0.04 and a 0 =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

9. The results so far…

10.  CDM @z=0

11. RPCDM @z=0

12. SUCDM @z=0

13.  CDM @z=0

14. RPCDM @z=0

15. SUCDM @z=0

16.  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