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VERSION:2.0
PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN
BEGIN:VEVENT
SUMMARY:The Strong Cosmological Coincidence Problem
DTSTART:20260917T143000Z
DTEND:20260917T160000Z
DTSTAMP:20260915T234116Z
UID:8cfc0a5a-52b8-4bad-a0c4-a8a929d47698
SEQUENCE:1
CREATED:20260914T083642Z
DESCRIPTION: The standard cosmological coincidence problem asks why matter
  and dark energy become dynamically comparable only close to the present e
 poch. I will discuss a stronger version of this problem\, motivated by the
  observation that the growing relative importance of dark energy coincides
  with the nonlinear development of cosmic structure.In several inhomogeneo
 us and coarse-grained descriptions\, quantities characterising structure f
 ormation evolve in a way that resembles the effective dark energy contribu
 tion inferred within the standard cosmological model.In this context\, I w
 ill introduce Buchert&#x27\;s scalar-averaging framework and its partition
 ing formalism\, which provide a natural way to separate the effects of int
 ernal regional dynamics from the variance of expansion rates between diffe
 rent regions. I will then discuss how the relativistic Zel&#x27\;dovich ap
 proximation can be used to close the averaged scalar equations.I will conc
 lude by outlining how the framework of inhomogeneous cosmology may provide
  a resolution of the strong cosmological coincidence problem. 
LAST-MODIFIED:20260914T083642Z
LOCATION:DF Seminar Room (2-8.3)\, 2nd floor of Physics Building
URL:http://df.vps.tecnico.ulisboa.pt/en/events/the-strong-cosmological-coi
 ncidence-problem/
X-ALT-DESC;FMTTYPE=text/html:<p data-block-key="soakc"> The standard cosmo
 logical coincidence problem asks why matter and dark energy become dynamic
 ally comparable only close to the present epoch. I will discuss a stronger
  version of this problem\, motivated by the observation that the growing r
 elative importance of dark energy coincides with the nonlinear development
  of cosmic structure.<br/></p><p data-block-key="370v8">In several inhomog
 eneous and coarse-grained descriptions\, quantities characterising structu
 re formation evolve in a way that resembles the effective dark energy cont
 ribution inferred within the standard cosmological model.<br/></p><p data-
 block-key="c70ts">In this context\, I will introduce Buchert&#x27\;s scala
 r-averaging framework and its partitioning formalism\, which provide a nat
 ural way to separate the effects of internal regional dynamics from the va
 riance of expansion rates between different regions. I will then discuss h
 ow the relativistic Zel&#x27\;dovich approximation can be used to close th
 e averaged scalar equations.<br/></p><p data-block-key="65kca">I will conc
 lude by outlining how the framework of inhomogeneous cosmology may provide
  a resolution of the strong cosmological coincidence problem. </p>
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