Frdric HenryCouannier

1
The Dark Side of Gravity and our Universe

• Frédéric Henry-Couannier
• CPPM/RENOIR Marseille
• www.darksideofgravity.com

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Motivations for alternativetheories of gravity

• Anomalous gravity effects?
• Pioneer effect
• Anisotropies in CMB quadrupôle
• Cosmology ?? GR Dark matter Inflation Dark
  energy ?!?!
• Local PN gravity tests dont tell us that GR is
  right in the cosmological domain !

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From non gravitational theory to GR

• Requirement equations should be invariant under
  general coordinate transformations
• Covariantisation program ? new field g???(and
  derivatives)
• g???is not only a pseudoforce but describes a
  genuine interaction gravity
• 1. 2. 3. simplicity ? GR satisfies by
  construction the equivalence principle.

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GR a geometric theory ?

• GR equations atomsphotons interact with g???
  field ? gravity affects the measured space and
  time intervals.
• g???has the properties of a metric
• The Geometrical viewpoint
• 1.2. ? g???is the metric of space-time. The
  geometrical properties of g???tell us about the
  geometry of space-time (Deformations, Curvature)?
• ? Trajectories geodesics

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The non geometrical viewpoint

• g???is just a field, spacetime is a flat and
  static manifold with true metric ???. ? many
  possibilities
• Keep GR the covariant theory of g???
• ?????is not observable (not in the equations!)?
•  Multimetric  theories
• Introduce two or more independent g???type fields
  (Petit, Linde, Damour)?
• Introduce ????in equations (Rosen)?
• Introduce?????through g???? g???is a Janus
  field
• Respect the symetry between the two faces
  ? Dark Gravity (mimics class 1.)?

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DG Gravity with its Dark side DG
mimics bigravity theories
Our side Srandard Model lives in gravity
Other side Standard Model
lives in gravity
?is dark from our side
viewpoint
Two gravities are related ?
anti-gravitational connection between 2 worlds

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DG rehabilitates global space-time symmetries

• Spacetime is flat as in QFT with metric ? we
  recover
• Global Lorentz-Poincaré invariance ? Noether
  currents
• Global space-time discrete symmetries and Lorentz
  group  bad  representations (negative energies,
  tachyons)?
• DG cosmological solution satisfies
• ? Two faces of our universe are conjugate under
  time reversal !

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DG equations

• T
• New equations

Extremum action eliminate
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Global space-time symmetries ? freeze degrees of
freedom

• Isotropic form
• Symmetry between space and time (links tachyons
  to bradions)?
• ? 2 theories
• and

Cosmology GW
Gravity Pioneer effect
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Local gravity

• As in Petit theory
• Objects living in the same gravity attract each
  other
• Objects living in different gravity reppel each
  other

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Schwarschild Gravity
DG RG
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Cosmology in DG
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Cosmology

• No source term (exact compensation) ? symmetries
  completely determine the universes global gravity
  
• Spatially flat universes
• No Big Bang singularity
• Constantly accelerated regime ? ?
• Negligible expansion rate in early universe
• Our universe is twice older than in SM

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Universe A(t)(dt2-d?2)?
Time reversal
GR Reversing time Going backward in time
t ? 8
Universe A(t)(dt2-d?2)?
Dark gravity Reversing time Jumping into
hidden face of universe
A-1(t)?
1
A(t)e-t
A(t) t -2
t ? 8
- 8???t
t0 Big Bang
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Magnitude vs redshiftSNA test (SCP 2003)?

• Fit a(t)?t?
• ????????

• 1.60.3(stat)?
• OK with constant acceleration
• 2

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From the CMB to large scale structures

• Universe expansion rate negligible relative to
  fluctuations growing rate
• Baryonic matter only, same density as in SM
• ?
• Exponentially growing fluctuations early reach
  the nonlinear regime

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No need for Dark Matter ?

• Universe twice older 26 billion years
• Oldest galaxies (z5) 17 billion years
• Repelling gravity ? each galaxy creates a void in
  conjugate universe equivalent to a Halo

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Other predictions of DG

• Longitudinal spin0 gravitational waves
• Different Schwarzschild solution (different PPN
  parameters, no BH)?
• Pioneer effect (postdiction)?
• Possibly new frame-dragging effects
• Gravitational discontinuity effects

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Conclusion

• DG is essentially the other option of a binary
• choice at the level of the conceptual fondations
  of GR
• DG has no coincidence problem, no epicycles
• DG is a stable theory with repelling gravity
• DG is OK with all local tests of gravity and
  explains the Pioneer anomaly
• DG provides a promissing framework to compete
  with the cosmological SM but DG needs detailed
  simulations to see if it can actually compete
  with (do better than SM?).

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RG vs DG

• The metric is the object one must use to raise
  and
• lower indices on any tensor field
• RG is the metric ?
• RG is the theory of
• DG is the metric ?
• DG is the theory of non independent
  and

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La symétrie x/t

• Forme la plus générale de
• ? If , C viole la symétrie x/t
• ?
  

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La symétrie x/t (II)?

• Si Ai
• ? Symétrie x/t OK
• ?

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Discontinuities in gravity ?
Discontinuity could have trapped 3.106 solar
masses lt 0 in twin universe ? mimics a
central BH
v
Conjugate universe void dominates idem dark
matter Halo
Matter dominates
r
?
A star