## Dark Energy and Dark Energy and

## Void Evolution Void Evolution

### Enikő Regős Enikő Regős

Astrophysical observations and quantum physics Astrophysical observations and quantum physics

Explain Explain ΛΛ from from

quantum fluctuations quantum fluctuations

in gravity in gravity

Radiative corrections Radiative corrections induce

induce ΛΛ

Quantum gravity and Quantum gravity and accelerator physics

accelerator physics

Quantum black holesQuantum black holes: : energy spectrum,

energy spectrum, dependence with dependence with

parameters of space- parameters of space-

times,

times, e.g.e.g. stringsstrings EntropyEntropy

### Quantum gravity and accelerator physics Quantum gravity and accelerator physics

Obtain limits from collider Obtain limits from collider experiments

experiments

Graviton interference effects at Graviton interference effects at Large Hadron Collider, CERN Large Hadron Collider, CERN

Decay modes of particles with Decay modes of particles with mass in TeV range

mass in TeV range

Hadron/lepton scatterings andHadron/lepton scatterings and decays in extra-dimensional decays in extra-dimensional

models models

Super symmetry, string theorySuper symmetry, string theory

Limits from cosmology Limits from cosmology and astrophysics:

and astrophysics:

cosmic rays and cosmic rays and

supernovae supernovae

Particle astrophysics Particle astrophysics

Dark matterDark matter

mass of particles, mass of particles, Ex:Ex: Axions Axions

Evidence fromEvidence from

observations for extra D observations for extra D

Alternative to missingAlternative to missing mass problemmass problem: : scale scale

dependent G dependent G

### Cosmic rays and supernovae ; Cosmic rays and supernovae ;

### Cosmic rays : Nature’s free collider Cosmic rays : Nature’s free collider

SN cores emit large fluxes of KK gravitons producing a SN cores emit large fluxes of KK gravitons producing a cosmic background -> radiative decays : diffuse

cosmic background -> radiative decays : diffuse γγ – ray – ray background

background

Cooling limit from SN 1987A neutrino burst -> bound on Cooling limit from SN 1987A neutrino burst -> bound on radius of extra dimensions

radius of extra dimensions

Cosmic neutrinos produce black holes, energy loss from Cosmic neutrinos produce black holes, energy loss from graviton mediated interactions cannot explain cosmic ray graviton mediated interactions cannot explain cosmic ray

events above a limit events above a limit

BH’s in observable collisions of elementary particles if EDBH’s in observable collisions of elementary particles if ED

CR signals from mini BH’s in ED, evaporation of mini BHsCR signals from mini BH’s in ED, evaporation of mini BHs

### Galaxy simulations and axion mass Galaxy simulations and axion mass

Collisional Cold Dark Matter interaction cross Collisional Cold Dark Matter interaction cross sections

sections

Halo structure, cuspsHalo structure, cusps

Number and size of extra dimensionsNumber and size of extra dimensions

High –z SNe: evolutionary effect in distance estimators ? High –z SNe: evolutionary effect in distance estimators ?

### Metallicity: Dependence with z Metallicity: Dependence with z

### Rates of various progenitors change with Rates of various progenitors change with age of galaxy

### age of galaxy

### Metallicity effect on C ignition density Metallicity effect on C ignition density

Neutrino cooling increased by URCA (21-Neutrino cooling increased by URCA (21- Ne - 21-F) slower light curve evolution → Ne - 21-F) slower light curve evolution →

at higher metallicities : small effect at higher metallicities : small effect

Empirical relation between max. luminosit

Empirical relation between max. luminosityy and and light curve shape (speed)

light curve shape (speed)

Systematic change with metallicity Systematic change with metallicity →→

### Field theories : Field theories :

### Cosmological constant induced by quantum Cosmological constant induced by quantum

### fluctuations in gravity fluctuations in gravity

One loop effective potential for the curvatureOne loop effective potential for the curvature

** ** ** ** **→** **→**

matter free Einstein gravity has 2 phases : matter free Einstein gravity has 2 phases :
flat and strongly curved space timesflat and strongly curved space times
Radiative corrections Radiative corrections

**→** **→**

Cosmological constant : Cosmological constant :
ΛΛ>0>0 for the curved and for the curved and ΛΛ<0<0 for the flat for the flat
Infrared Landau pole in Infrared Landau pole in ΛΛ>0 phase: >0 phase:

**→** **→**

Graviton confinement Graviton confinement (unseccessful attempts of (unseccessful attempts of
experiments)
experiments)

Or running Newton constantOr running Newton constant

### Effective potential as function of curvature

### Effective potential as function of curvature

### Casimir effect Casimir effect

Attractive force between neutral plates in QEDAttractive force between neutral plates in QED

Depends on geometry (e.g. not parallel)Depends on geometry (e.g. not parallel)

Zero point energyZero point energy

Metric tensor controls geometry :Metric tensor controls geometry :

analogy with gravity :analogy with gravity :

Fit numerical results for gravityFit numerical results for gravity

### Energetically preferred curvature Energetically preferred curvature

Minimize effective potentialMinimize effective potential

Quantum phase transitionQuantum phase transition

Savvidy vacuum :Savvidy vacuum :

QCD vacuum in constant magnetic field unstable QCD vacuum in constant magnetic field unstable

coupling (constant) depends on external B coupling (constant) depends on external B

similarly in gravity G depends on external similarly in gravity G depends on external gravitational field

gravitational field

### Induced

### Induced Λ Λ and R and R ² ² : :

In actionIn action

F ( R ) = R – 2 F ( R ) = R – 2 λλ – g R² – g R²

stabilizes gravity stabilizes gravity

( R( R² inflation² inflation , ,

conformally invariant to conformally invariant to quintessence quintessence

- cosmological evolution )- cosmological evolution )

### Stability and matter fields Stability and matter fields

λλ_bare -> 2D _bare -> 2D phase diagramphase diagram

include matter fieldsinclude matter fields : :

1.1. scalarscalar

2.2. strong interaction : strong interaction :

influence of confinement in gauge andinfluence of confinement in gauge and

gravitational sectors on each othergravitational sectors on each other

gravitational waves gravitational waves

### 2

### 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

### 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

### Formation and evolution of voids

In a Λ–CDM Universe :

w

1. distribution of void sizes in various simulations, Λ

2. 2MASS survey, Λ

## Cosmological parameters from Cosmological parameters from

## 6dF 6dF

### 2MASS, Aitoff projection

## cz < 3000 km / s

## cz < 3000 km / s

## 3000 km / s < cz < 6000 km / s

## 3000 km / s < cz < 6000 km / s

## Voids in 2MASS Voids in 2MASS

### Supergalactic coordinates Supergalactic coordinates

### Supergalactic plane Supergalactic plane

### Equatorial coordinates Equatorial coordinates

### Peculiar velocity data Peculiar velocity data

### Cosmological parameters from outflow Cosmological parameters from outflow velocities

### velocities

## Big voids Big voids

### Because it is an infrared survey Because it is an infrared survey the voids are shallower the voids are shallower

### less underdense than in optical less underdense than in optical

### Interpretation of velocities

### Not a simple dipole