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cosmodynamics

Explore the concepts of cosmodynamics, including quintessence, the fifth force, and time-varying fundamental constants. Learn how to distinguish between quintessence and the cosmological constant, and understand the possible coupling between dark energy and dark matter.

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cosmodynamics

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  1. cosmodynamics • quintessence • fifth force • violation of equivalence principle • time varying fundamental constants

  2. How to distinguish Q from Λ ? A) Measurement Ωh(z) H(z) i) Ωh(z) at the time of structure formation , CMB - emission or nucleosynthesis ii) equation of state wh(today) > -1 B) Time variation of fundamental “constants” C) Apparent violation of equivalence principle D) Possible coupling between Dark Energy and Dark Mater

  3. Cosmodynamics Cosmon mediates new long-range interaction Range : size of the Universe – horizon Strength : weaker than gravity photon electrodynamics graviton gravity cosmon cosmodynamics Small correction to Newton’s law

  4. “Fifth Force” • Mediated by scalar field • Coupling strength: weaker than gravity ( nonrenormalizable interactions ~ M-2 ) • Composition dependence violation of equivalence principle • Quintessence: connected to time variation of fundamental couplings R.Peccei,J.Sola,C.Wetterich,Phys.Lett.B195,183(1987) C.Wetterich , Nucl.Phys.B302,645(1988)

  5. Violation of equivalence principle Different couplings of cosmon to proton and neutron Differential acceleration “Violation of equivalence principle” p,n earth cosmon p,n only apparent : new “fifth force” !

  6. Differential acceleration Two bodies with equal mass experience a different acceleration ! η = ( a1 – a2 ) / ( a1 + a2 ) bound : η < 3 10-14

  7. Cosmon coupling to atoms • Tiny !!! • Substantially weaker than gravity. • Non-universal couplings bounded by tests of equivalence principle. • Universal coupling bounded by tests of Brans-Dicke parameter ω in solar system. • Only very small influence on cosmology.

  8. Cosmon coupling to Dark Matter • Only bounded by cosmology • Substantial coupling possible • Can modify scaling solution and late cosmology • Role in clustering of extended objects ? L. Amendola

  9. Quintessence and time variation of fundamental constants Generic prediction Strengthunknown Strong, electromagnetic, weak interactions C.Wetterich , Nucl.Phys.B302,645(1988) gravitation cosmodynamics

  10. Time varying constants • It is not difficult to obtain quintessence potentials from higher dimensional or string theories • Exponential form rather generic ( after Weyl scaling) • But most models show too strong time dependence of constants !

  11. Are fundamental “constants”time dependent ? Fine structure constant α (electric charge) Ratio electron mass to proton mass Ratio nucleon mass to Planck mass

  12. Quintessence and Time dependence of “fundamental constants” • Fine structure constant depends on value of cosmon field : α(φ) (similar in standard model: couplings depend on value of Higgs scalar field) • Time evolution of φ Time evolution of α Jordan,…

  13. Standard – Model of electroweak interactions :Higgs - mechanism • The masses of all fermions and gauge bosons are proportional to the ( vacuum expectation ) value of a scalar field φH ( Higgs scalar ) • For electron, quarks , W- and Z- bosons : melectron = helectron * φHetc.

  14. Restoration of symmetryat high temperature in the early Universe high T : less order more symmetry example: magnets Low T SSB <φH>=φ0≠ 0 High T SYM <φH>=0

  15. In the hot plasma of the early Universe :No difference in mass for electron and muon !

  16. Quintessence :Couplings are still varying now !Strong bounds on the variation of couplings -interesting perspectives for observation !

  17. baryons : the matter of stars and humans Ωb = 0.045

  18. Abundancies of primordial light elements from nucleosynthesis A.Coc

  19. Allowed values for variation of fine structure constant : Δα/α ( z=1010 ) = -1.0 10-3 GUT 1 Δα/α ( z=1010 ) = -2.7 10-4 GUT 2 C.Mueller,G.Schaefer,…

  20. Variation of fine structure constant as function of redshift Three independent data sets from Keck/HIRES Δα/α = - 0.54 (12) 10-5 Murphy,Webb,Flammbaum, june 2003 VLT Δα/α = - 0.06 (6) 10-5 Srianand,Chand,Petitjean,Aracil, feb.2004 z ≈ 2

  21. Atomic clocks and OKLO assumes that both effects are dominated by change of fine structure constant

  22. Time variation of coupling constants must be tiny – would be of very high significance ! Possible signal for Quintessence

  23. Πανταρει Everything is flowing

  24. Apparent violation of equivalence principle and time variation of fundamental couplings measure both the cosmon – coupling to ordinary matter

  25. Differential acceleration η For unified theories ( GUT ) : η=Δa/2a Q : time dependence of other parameters

  26. Link between time variation of α and violation of equivalence principle typically : η = 10-14 if time variation of α near Oklo upper bound to be tested ( MICROSCOPE , …)

  27. End

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