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Dark Energy and Void Evolution

Dark Energy and Void Evolution. Enikő Regős. Explain Λ from quantum fluctuations in gravity Radiative corrections induce Λ. Quantum gravity and accelerator physics Quantum black holes : energy spectrum, dependence with parameters of space-times, e.g. strings Entropy.

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Dark Energy and Void Evolution

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  1. Dark Energy and Void Evolution Enikő Regős

  2. Explain Λ from quantum fluctuations in gravity Radiative corrections induce Λ Quantum gravity and accelerator physics Quantum black holes: energy spectrum, dependence with parameters of space-times,e.g.strings Entropy Astrophysical observations and quantum physics

  3. Obtain limits from collider experiments Graviton interference effects at Large Hadron Collider, CERN Decay modes of particles with mass in TeV range Hadron/lepton scatterings and decays in extra-dimensional models Super symmetry, string theory Limits from cosmology and astrophysics: cosmic rays and supernovae Particle astrophysics Dark matter mass of particles, Ex: Axions Evidence from observations for extra D Alternative to missing mass problem: scale dependent G Quantum gravity and accelerator physics

  4. Cosmic rays and supernovae ;Cosmic rays : Nature’s free collider • SN cores emit large fluxes of KK gravitons producing a cosmic background -> radiative decays : diffuse γ – ray background • Cooling limit from SN 1987A neutrino burst -> bound on radius of extra dimensions • Cosmic neutrinos produce black holes, energy loss from graviton mediated interactions cannot explain cosmic ray events above a limit • BH’s in observable collisions of elementary particles if ED • CR signals from mini BH’s in ED, evaporation of mini BHs

  5. Galaxy simulations and axion mass • Collisional Cold Dark Matter interaction cross sections • Halo structure, cusps • Number and size of extra dimensions

  6. High –z SNe: evolutionary effect in distance estimators ? • Metallicity: Dependence with z • Rates of various progenitors change with age of galaxy • Metallicity effect on C ignition density • Neutrino cooling increased by URCA (21-Ne - 21-F) → slower light curve evolution at higher metallicities : small effect

  7. Empirical relation between max. luminosity and light curve shape (speed) Systematic change with metallicity → far ELD SNe Ia fainter

  8. Field theories :Cosmological constant induced by quantum fluctuations in gravity • One loop effective potential for the curvature → matter free Einstein gravity has 2 phases : flat and strongly curved space times • Radiative corrections → Cosmological constant : Λ>0 for the curved and Λ<0 for the flat • Infrared Landau pole in Λ>0 phase: →Graviton confinement (unseccessful attempts of experiments) • Or running Newton constant

  9. Effective potential as function of curvature

  10. Casimir effect • Attractive force between neutral plates in QED • Depends on geometry (e.g. not parallel) • Zero point energy • Metric tensor controls geometry : analogy with gravity : • Fit numerical results for gravity

  11. Energetically preferred curvature • Minimize effective potential • Quantum phase transition • Savvidy vacuum : QCD vacuum in constant magnetic field unstable • coupling (constant) depends on external B • similarly in gravity G depends on external gravitational field

  12. Induced Λ and R² : • In action F ( R ) = R – 2 λ – g R² • stabilizes gravity • ( R² inflation , conformally invariant to quintessence - cosmological evolution )

  13. Stability and matter fields • λ_bare -> 2D phase diagram • include matter fields : • scalar • strong interaction : influence of confinement in gauge and gravitational sectors on each other • gravitational waves

  14. 2

  15. Growth factors, Λ≠ 0 • f ≈ Ω^0.6_m + (1 + Ω_m /2 ) λ / 70 • enters the peculiar velocity too • equation of state, w • Alcock – Paczynski effect

  16. Spherical voids in Λ≠ 0 • coasting period provides more time for perturbations to grow • reducing the initial density contrast needed to produce nonlinear voids for fixed Ω_0, Λ ~ H²_0 • good for ΔT/T of CMB • density - velocity relation : model – independent, including biasing

  17. Formation and evolution of voids • In a Λ–CDM Universe : • w • distribution of void sizes in various simulations, Λ • 2MASS survey,Λ

  18. Cosmological parameters from 6dF

  19. 2MASS, Aitoff projection

  20. cz < 3000 km / s

  21. 3000 km / s < cz < 6000 km / s

  22. Voids in 2MASS • Supergalactic coordinates • Supergalactic plane • Equatorial coordinates • Peculiar velocity data • Cosmological parameters from outflow velocities

  23. Big voids • Because it is an infrared survey the voids are shallower less underdense than in optical

  24. Interpretation of velocities • Not a simple dipole • Not a simple quadrupole (infall onto plane) Magnitude of radial velocities : variation with angle (Differential) Outflow: H_0 r Ω^0.6 / 5

  25. Thank you for your attention

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