COSMOLOGY

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COSMOLOGY
International Meeting of Fundamental
Physics (Winter meeting) Santiago de
Compostela, 2007
Eduard Massó UAB/IFAE
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Program

• The standard cosmological model
• The observed universe
• Inflation. Neutrinos in cosmology

Emphasis on Particles
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Science, vol. 315, 2007
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Our universe is expanding
lights-years ago
co-moving distance
scale
today
redshift
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Co-moving co-ordinates
On top peculiar (real) velocities
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Hubbles law Cosmological principle
Universe homogenous isotropic on large scales
Cosmological principle
Hubble parameter
(today)
Hubbles discovery
Hubbles law
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Expansion (or contraction) is inevitable
Robertson-Walker metric (homogeneity isotropy)
Parameters
Content (matterradiation)
Content too (cosm. const.)
Parameters are related by eqs.
Spatial geometry
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Cosmological equations
Friedmann eqs.
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2a
12a -gt 2b
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Spatial geometry Light propagation
Open
Closed
FLAT
3D
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Spatial geometry Light propagation
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Luminosity distance
Absolute luminosity E/time in rest frame
Measured flux (E/time/area)
Luminosity distance
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Hubbles law
Exact
Small z
Deceleration parameter
That was kinematics
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Cosmological constant contribution
Negative pressure
any other component
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Solution to cosmological eqs.
Equation of state
Assume i - dominance and
RD universe
MD universe.
CCD universe
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Critical density
Define
Define also (Today)
Not energy-density contribution
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Rewriting Friedmann eqs.
Cosmic sum rule
2a today
Notice signs
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The future
Diff. eq.
Initial conditions taken today
Eternal Expansion OR Recollapse ?
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2
3
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Distance - Redshift
Co-moving distance to source
Where
Can neglect
Distance-redshift relation is function of
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Age of the universe
look-back time
lifetime
Flat univ.
Our univ.
(Age crisis Open universe gave too low lifetime)
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Which universe ?
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The past universe
nucleosynthesis
rad
recombination
mat
cc
equality
today
next
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The hot universe
Equilibrium thermodynamics
g deg. of freedom
number density
energy density
pressure
distribution
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Decoupling of species
Expansion Interaction
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Phase transitionsSymmetry restoring
2n order
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Phase transitions
1st order
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Conformal time
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Particle Horizon
It is the physical distance photons can travel
until a time t
Defines causal distance at a given time t
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Program

• The standard cosmological model
• The observed universe
• Inflation. Neutrinos in cosmology