Cosmological Acceleration and Inhomogeneities| Cosmological Acceleration and Inhomogeneities |
In General
> s.a. acceleration [observations, tests]; dark
energy; expansion; cosmological models;
averaging in cosmology [back-reaction].
* Idea: Attempts to explain the
observed acceleration using only general relativity with baryonic and cold dark
matter, but by dropping the standard assumption of homogeneity on Hubble scales.
* Timescape cosmology:
An approach in which the present age of the universe varies by billions of
years according to the position of the observer; A model in which cosmic
acceleration is realized as an apparent effect related to the calibration
of clocks and rods of observers in bound systems relative to volume-average
observers in an inhomogeneous geometry in ordinary general relativity, due
to gravitational energy gradients that grow when spatial curvature gradients
become significant with the non-linear growth of cosmic structure.
* Void models: The supernova data
can be explained if we live near the center of a Hubble-scale void; However,
such void models have been shown to be inconsistent with various observations;
2010, They seem to be ruled out by measurements of the kinematic SZ effect;
2012, Loopholes closed; > s.a. cosmological principle.
@ Reviews:
Célérier ap/06-proc,
ap/07-in;
Buchert GRG(08)-a0707;
Tomita a0906-conf [assessment];
Tetradis a1002-conf;
Räsänen CQG(11)-a1102;
Célérier a1203-proc.
@ General references: Dabrowski G&C(02)gq/99;
Célérier A&A(00)ap/99;
Pascual-Sánchez MPLA(99)gq,
gq/99-proc;
Bene et al MPLA(06)ap/03;
Barausse et al PRD(05)ap;
Kolb et al ht/05,
Wiltshire gq/05 [primordial inflation];
Moffat ap/05,
JCAP(06)ap/05,
ap/06;
Kolb et al NJP(06)ap/05 [invalidation of no-go results];
Martineau & Brandenberger ap/05;
Alnes et al PRD(06)ap/05;
Mansouri ap/05;
Kai et al PTP(07)gq/06;
Leith et al ApJ(08)-a0709;
Djorgovskia & Gurzadyan NPPS(07);
Paranjape & Singh JCAP(03)-a0801;
Larena et al PRD(09)-a0808;
Krasiński et al GRG(10)-a0903;
Räsänen PRD(10);
Kolb CQG(11);
Bochner a1109-conf,
a1109,
IJMPD(13)-a1206 [causal backreaction in a smoothly-inhomogeneous universe];
Romano GRG(13)-a1206;
Krasiński PRD(14)-a1309 [ΛCDM model vs Λ = 0 Lemaître-Tolman model];
Skarke PRD(14)-a1310 [acceleration from the distribution of scalar spatial curvature].
@ Timescape: Wiltshire NJP(07)gq,
IJMPD(08)-a0712,
in(08)-a0712;
Wiltshire PRD(09) [test, averages],
IJMPD(09)-a0912-FQXi [Cosmological Equivalence Principle];
Smale & Wiltshire MNRAS(11)-a1009 [supernova tests];
Wiltshire a1102-proc;
Balasin a1310 [manifest realization];
Wiltshire a1311-proc [rev];
Nazer & Wiltshire PRD(15)-a1410 [cmb anisotropies];
Dam et al MNRAS(17)-a1706;
news Cosmos(17)sep;
> s.a. averaging.
@ Swiss-cheese model: Biswas & Notari JCAP(08)ap/07;
Vanderveld et al PRD(08)-a0808;
Bene & Csapo a1002.
@ Void models: Caldwell & Stebbins PRL(08)-a0711 [apparent acceleration from local void];
Mattsson GRG(09)-a0711;
Quartin & Amendola PRD(10)-a0909 [distinguishing from dark energy];
Kainulainen & Marra AIP(10)-a0911 [small-void + meatball model];
Biswas et al JCAP(10)-a1007 [fitting observations],
PRD(10) [as a probe of dark energy];
Moss et al PRD(11)-a1007 [problems with data];
Bolejko & Sussman PLB(11)-a1008 [non-spherical];
Foreman et al PRD(10)-a1009 [spatial and temporal fine-tuning];
Nadathur & Sarkar PRD(11)-a1012 [and the cmb];
Marra & Notari CQG(11)-a1102 [observational constraints];
> s.a. matter; observation [statistics].
@ Dark energy vs underdense void: Moffat a0910.
Arguments Against an Inhomogeneity Effect
* Idea: Some models, notably
by Green and Wald, argue that inhomogeneities have a very small backreaction
effect on averaged properties of the universe, such as the observed acceleration;
Critics claim that those results may be correct under the assumptions used in
the arguments, but the assumptions do not capture well the physical situation
of interest in cosmology.
@ General references: Geshnizjani et al PRD(05)ap;
Flanagan PRD(05)ht;
Hirata & Seljak PRD(05)ap;
Räsänen CQG(06)ap/05;
Siegel & Fry ApJL(05)ap;
Ishibashi & Wald CQG(06)gq/05 [general arguments];
Kasai et al PTP(06)ap;
Rosenthal & Flanagan a0809;
Zibin et al PRL(08)-a0809;
Paranjape & Singh PRL(08) [model];
Paranjape PhD(09)-a0906;
Ziaeepour a0906 [summary];
Romano JCAP(10)-a0912;
Green & Wald PRD(11)-a1011 [framework for effect of perturbations];
Zibin PRD(11)
[decaying modes and expected cosmic microwave background spectral distortion].
@ Criticism of arguments: Buchert et al CQG(15)-a1505
& CQG+(16),
response Green & Wald a1506,
CQG(16)-a1601.
Related Topics
> s.a. Copernican Principle; inflation
and phenomenology [fluctuations]; LTB
Solutions; Stephani Model.
@ And structure formation: Biswas et al JCAP(07) [non-linear structure formation];
Räsänen IJMPD(08),
a0811-proc;
Wiegand & Buchert a1103-conf;
Buchert PoS-a1810.
@ Effects: Regis & Clarkson GRG(12)-a1003 [and lithium-abundance mismatch];
Buchert a1012-conf
[and emerging "morphon" scalar field].
@ From quantum fluctuations:
Padmanabhan CQG(05)ht/04;
Ringeval et al PRL(10)-a1006 [during inflation];
> s.a. theory of cosmological acceleration.
@ Other models: Hossain a0709 [FLRW islands surrounded by vacuum];
Ishak et al PRD(08)-a0708 [Szekeres model];
Mattsson GRG(10);
Collins a1011 [with periodic variation in one direction];
Célérier A&A(12)-a1108 [clarification];
Bueno & Perivolaropoulos PRD(11)-a1110
["topological quintessence", topological defect formed during a recent phase transition].
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