The physics of inflation and dark energy

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The physics of inflation and dark energy
1.3 Dark energy some evidence (short list)

• SN Ia W L - W m _at_ 0.3

• CMB W L W m _at_ 1.0

• Large scale motions 0.15 lt W m lt
  0.4

• Ages of glob. clusters/galaxies at z2-3 W m lt
  0.6

• Cluster mass function W m 0.3

Bottom line many indep. hints that Wm
0.35 W L 0.65 (W K 0.0)
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The physics of inflation and dark energy
2. How to achieve acceleration
2.1 Physical basis

• Newtonian physics ?

DENIED
...only mass is a source for gravity in Newtonian
physics
gt gravity is always attractive...

• Einsteins theory ?

APPROVED
...energy density and pressure are components of
a tensor (the stress-energy tensor Tab) and both
are sources for gravity
gt gravity can be repulsive (cosmologically) if
pressure is sufficiently negative !
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The physics of inflation and dark energy
2.2 Einstein, Friedman, de Sitter...
FRW geometry
Friedman equations
pgt-r/3 decceleration
plt-r/3 acceleration
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The physics of inflation and dark energy
2.3 Can pressure ever be negative?
General equation of state pX wX rX
wX wX (t)
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The physics of inflation and dark energy
2.4 Pressure and energy density conservation
Energy conservation law in FRW
wX constant
wRad 1/3 wDust 0 wL -1 wX ...
If X is dominant
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The physics of inflation and dark energy
2.5 Life in an accelerating spacetime