nonlinear cosmological probes of screening mechanisms in modified...
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David F. Mota
Institute of Theoretical Astrophysics University of Oslo
Nonlinear Cosmological Probes of Screening Mechanisms in Modified Gravity
Scalar-Tensor Theories with Chameleon or Symmetron screening mechanisms
10-3cm 1AU 1kpc 1Mpc 1000Mpcextra dimensions? GR Modified Gravity?
Extremely tight constraints on Modified Gravity from experiments at small scales!
Cassini ProbeLunar Laser Range
SupernovaeSupernovae + Large Scale StructuresSupernovae + Large Scale Structures + CMBRSupernovae + Large Scale Structures + CMBR + Baryon Oscillations
Decelerated Expansion
Accelerated Expansion
PLANCK
SDSS
High-Z Supernovae Search Team
GR
Large Scale Structure Formation: deviations from GR must be small
Amargui,Elgaroy, DFM, A&A
GRf(R)
Structure formation probes deviations from GR
Llinares, DFM & Winther, ApJ
rStronger coupling -> bigger deviations from LCDM Larger range -> large scale deviations from LCDM
Short range Long range
Structure formation dependence on coupling and range
r
Llinares, DFM & Winther, ApJ
screening at high densities
Structure formation dependence on the screening scale
Chameleon screening
critical scale
screening at high densities
screening at low densitiesscreening at low densities
Symmetron screening
Gronke, Llinares, DFM, A&A
Very difficult to differentiate between Chameleon and Symmetron
f
VeffHfL
f
VeffHfL
ScreenedUnscreened!
Symmetron Unique Feature
Symmetron Domain Wallsf
VeffHfL
f
VeffHfL
Llinares & DFM, PRL
-0.015
-0.01
-0.005
0
0.005
0.01
0.015
0.1 1 10
(Pfu
ll-Pst
atic
)/Pst
atic
k (h/Mpc)
(32,0,64)(32,32,64)(32,64,64)(32,96,64)
Probing Symmetron with Local Power Spectrum
Llinares & DFM, PRL
Summary
} If one wants probe Modified Gravity then: } one should look at structure formation } Effects are stronger within the fifth force range and
proportional to the coupling } Nonlinear regime is the most interesting!
} If one wants to probe screening mechanisms then: } Global observables may not do the job } Only local observables with an environmental dependence can
be smoking guns
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