Cosmology from decaying dark energy, primordial at the Planck scale
Transcript of Cosmology from decaying dark energy, primordial at the Planck scale
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Cosmology from decaying darkenergy, primordial at the Planck scale
•Why is the dark-energy density similar to theuniverse’s?•Why does it differ from the Planck energy density by122 orders of magitude?
Jaime BesprosvanyInstituto de Física, UNAM
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Contents• The cosmological constant• Coincidence and fine-tuning problems• Standard cosmological equations• Supernova redshift relation• Time relation• Cosmic rays• Future work and conclusions
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The cosmological constant
• Introduced by Seeliger and Neumann in the 1890’s to create a static universe
• Applied to general relativity by Einstein in 1919
• Zeldovich associated it to the quantum vacuum in 1967
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Coincidence problem
Today: dark energy dark matter baryonic matter
Fine-tuning problemToday: critical density
Planck time: Planck density
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Standard cosmological equations•General relativity
•FRW metric (isotropy)
•Flat universe
•Perfect fluid at rest
-00 component of Einstein equations
-contraction of Einstein equations: energy conservation
within and expanding volume
Hubble constant
Parametricdependence onV,t,R,T, etc.
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Independent components
GR Energy conservation Thermodynamics
generalization
Matter p=0 T=0 dN=0 ??
radiation p=(1/3)ρ T=(ρ/a) µ=0
dark-energy p=wρ dS =0 ??
1/3
generalization
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Dark-energy equation of state
•Extensiveness: Need such a thermodynamic quantity
•Presence of quanta
p=wρ
E=cV c-constant-w
N dependence
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Dark-energy’s chemical potential
Extensiveness
Zero-temperature
Radiation-like
p=wρ
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Intermediate case
Zero-temperature
Radiation-like
Limits
for
for
Polytropic gas
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Dark-energy chemical potentialcontribution
Part
(1) (2)
Using, dV=d(R )=3R R dt23.
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Part
Zero-temperature
Small temperature
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Two-component model1) Dark-energy conservation
2) Total energy conservation
3) 00 component of Einstein equations
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Scale-factor dependence
Dark energy
other dominant component
baryonic matter
Asymptotic limit
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Time relations
Planck time
general equation of state
standard cosmology
decaying dark-energy
can explain fine tunning!
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Supernova data
distance-redshift relation
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Cosmic Rays
Spectrum in the highest energy range
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Cosmic Rays
Galactic origin up to
Emissivity
Energy density
Dark energy decays to dark matter
gravitational interaction
mass of intermediary particle
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Conclusions-The model represents a departure from the zero-temperature cosmological constant.-It maintains the results of the standard cosmology.-Dark energy's coincidence with the critical density today is connected to theuniverse evolution.-This favors contingency, rather than chance.-Account of dark energy's quanta connects today's energy-density scale withPlanck's, within classical general relativity and thermodynamics.-The universe emerges as flat, interconnected, evolving deterministically, and in aninexorable process of accelerated expansion and decay.
Future work-Structure formation-Cosmic background radiation-Inflation-Microscopic basis of dark-energy equation of state
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C a n t i d a d S í m b o l o V a l o r
Constante Gravitacional G 6.673 x 10-11 m3 kg-1 seg-2
Velocidad de la luz en el vacío c 299,792,458 m seg-1
Constante de Planck h 6.626 x 10-34 m kg seg-1
C a n t i d a d S í m b o l o E c u a c i ó n V a l o r
Longitud de Planck lP
l P =hG
c3
4 . 0 5 1 x 1 0-35
m
T i e m p o d e P l a n c k tP
tP
=hG
c5
1.351 x 10-43 seg
C a n t i d a d S í m b o l o E c u a c i ó n V a l o r
Longitud de Planck lP
l P =
hG
c3
4 . 0 5 1 x 1 0-35
m
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Early universe
Matter domination: structure formation: dark energy
Radiation domination: nucleosynthesis: dark energy
Dark energy
Dark matter component
baryonic matter
radiation
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Time constraints
Radiation
Average
Recent
Consistency: time of the universe until dark-energybaryon density equality
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Nature's constants
C a n t i d a d S í m b o l o V a l o r
Constante Gravitacional G 6.673 x 10-11 m3 kg-1 seg-2
Velocidad de la luz en el vacío c 299,792,458 m seg-1
Constante de Planck h 6.626 x 10-34 m kg seg-1
Natural units of length,time, mass
Planck length 4.051 x 10-35 mPlanck time 1.351 x 10-43 segPlanck mass 5.456 x 10-8 kg
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Solutions and asymptotic behavior
Exact solution
Asymptotic limit
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