Acceleration
of the Cosmological Expansion Rate| Acceleration
of the Cosmological Expansion Rate |
Observations > s.a. star
types [supernovas].
* Status: 1998, Contrary
to standard wisdom, the expansion seems to be accelerating, from observation
of 80 supernovas out to z = 0.8; 2002, q0 = –0.56 
0.04;
Many models proposed, most assuming that the current acceleration began at
z 
1; 2004,
Chandra observations confirm acceleration began about 6 Gyr ago; 2007, SNLS
3rd year data to be released with 250 new supernovas, SNAP mission will yield
about 2000 supernovas per year and will be able to exclude many proposed explanations.
@ Reviews: Filippenko PASP(01)ap;
Ostriker & Steinhardt SA(01)jan; Schmidt CQG(02);
Leibundgut & Sollerman
EPN(02)ap/02;
Perlmutter PT(03)apr;
Riess & Turner SA(04)feb [onset]; Shapiro & Turner ApJ(06)ap/05 [without
general relativity]; Perivolaropoulos ap/06-in;
news pw(07)dec,
Krauss pw(07)dec,
Crease pw(07)dec
[X anniversary]; Krauss & Scherrer SA(08)mar.
@ General references: Mannheim PRD(98)ap [implications],
ap/98-in;
Riess et al AJ(98)ap;
Perlmutter et al ApJ(99)ap/98,
ap/98-in,
PRL(99)ap;
Sidharth hp/98-in;
Starkman et al PRL(99)ap;
Straumann EJP(99)ap;
Turner ap/99-in;
Liddle NAR(01)ap/00;
Updike PT(05)apr;
Gong & Wang PRD(06)
[constraints]; Rapetti et al MNRAS(07)ap/06
[kinematical study]; Cattoen & Visser gq/07 [case
less watertight than usually assumed]; Daly & Djorgovski a0710-in;
Durrer & Maartens a0711-GRG
[rev]; Albrecht a0710-in
[case for aggressive observational program]; Bolejko & Andersson a0807 [apparent
and average acceleration].
@ Supernovae: Drell et al ApJ(00)ap/99;
Gott et al ApJ(01)ap/00;
Riess PASP(00)ap;
et al ApJ(01)ap;
Filippenko ap/03-in;
Jain & Ralston ApJ(06)ap/05;
SNAP ap/05-rp
[goals]; Gong et al JCAP(07),
Seikel & Schwarz JCAP(08)-a0711 [model-independent
evidence]; Leibundgut GRG(08)-a0802.
@ Galaxy redshift surveys: Guzzo et al Nat(08)-a0803.
@ Gravitational waves: Seto et al PRL(01)ap [0.1
Hz, proposal].
Theory, Explanations > s.a. dark
energy; expansion;
cosmological models; K-Essence; kaluza-klein; relativistic
cosmological models.
* Explanations: They
include a cosmological constant, quintessence or other fields (e.g., k-essence),
modified gravity (such as f(R) theories), inhomogeneities, semiclassical
effects, trans-Planckian fluctuations, or anti-friction in CDM, and some form
of antigravity; Observations can discriminate between them (for example, a
cosmological constant implies
dw/dz = 0, quintessence dw/dz > 0 and
k-essence dw/dz <
0); Another class of explanations is that some physics
(e.g., non-linear electromagnetism) affects the observed redshift-luminosity
relationship we see for a given expansion history.
* Status: 2005, Kolb
et al suggested that the acceleration is due to super-horizon inhomogeneities
from
primordial fluctuations; 2006, Consensus seems to be that
inhomogeneity effects may be present, but they are too small; 2007, Model suggests
that inhomogeneities can also partly mimic an acceleration by
affecting
light
propagation.
@ Reviews and general: Carroll ap/03-in;
Easson ap/04-in;
Szydlowski et al PLB(06)ap [top
10 models]; Bludman ap/06;
Uzan GRG(07)ap/06;
Silva e Costa & Makler ap/07 [relationships];
Ruíz-Lapuente CQG(07)-a0704;
Frieman et al a0803-ARAA.
@
Dark
energy vs modified theory: Szydlowski & Godlowski PLB(06)ap/05;
Capozziello et al PLB(06);
Huterer & Linder PRD(07)ap/06;
Ishak et al PRD(06);
Barger et al PLB(07)ap/06;
Kunz & Sapone PRL(07)ap/06,
Bertschinger & Zukin PRD-a0801 [difficult
to distinguish]; Buzzi et al a0806;
Zhang et al PLB(08).
@ Cosmological constant: Giulini & Straumann ap/00.
@ Semiclassical effects: Parker & Raval PRD(99)gq,
PRL(01); Parker et al ap/02/ApJ;
Parker & Vanzella PRD(04)gq/03;
Padmanabhan CQG(05)ht/04 [vacuum
fluctuations]; Caldwell PRD(06)ap/05 [gravitational
phase transition].
@ Quantum cosmology: Pinto-Neto & Santini PLA(03)
[FRW + scalar]; Tsamis & Woodard CQG(05)gq [measure
of back-reaction].
@ Brans-dicke theory: Banerjee & Pavón
PRD(01)gq/00,
CQG(01)gq/00; Sen & Sen
PRD(01).
@ Higher-order gravity: Capozziello
IJMPD(02)gq,
et al GRG(06)ap/04,
et al PRD(05)ap,
et al JCAP(06)ap;
Carroll et al PRD(04)ap/03 [R–n, n >
0]; Nojiri & Odintsov PRD(03)ht;
Vollick PRD(03)ap [R-
2/R];
Folomeev et al ap/05;
Multämaki & Vilja PRD(06)ap/05;
Nojiri & Odintsov PLB(05)ht [Einstein-Gauss-Bonnet];
Hu & Sawicki PRD(07).
@ Extra dimensions: Gu & Hwang PRD(02)ap/01;
Chatterjee et al IJMPA(06)gq/05;
Panigrahi et al IJMPA(06)gq;
Wesley a0802 [no-go].
@ Brane world: Dvali SA(04)feb; Padilla CQG(05);
Galfard et al CQG(06)
[mirage inhomogeneities]; Maartens & Majerotto PRD(06)ap,
Gabadadze ap/06 [self-acceleration];
Koyama a0706-GRG
[rev]; Koshelev & Tomaras JHEP(07)-a0706 [self-acceleration,
covariant model]; Charmousis et al JCAP(07)
[stealth acceleration].
@ Other modified gravity: Moffat ap/01;
Lue et al PRD(04)ap/03;
Nojiri & Odintsov
PLB(03)ht [M-theory];
Dolgov & Kawasaki PLB(03)ap [instability];
Dehghani PRD(04)
[Gauss-Bonnet gravity]; Nojiri & Odintsov ht/04-in
[+ sudden singularities]; Trodden ap/06-in
[rev]; Verozub a0805; > s.a. scalar-tensor
theories.
@ String-motivated: Albrecht & Skordis PRL(00);
Sheykhi et al PRD(07)-a0704.
@ Other quantum-gravity-motivated: Briscese a0704 [minimal
length]; Maziashvili PLB(07)-a0705,
Cai a0707 [Károlyházy
uncertainty relation]; Deser & Woodard PRL(07)-a0706 [non-local
gravity].
@ Inhomogeneities: Dabrowski G&C(02)gq/99;
Célérier A&A(00)ap/99;
Pascual-Sánchez
MPLA(99)gq, gq/99-in;
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 gq/06;
Célérier
ap/06-in,
ap/07-in
[rev]; Wiltshire NJP(07)gq,
IJMPD(08)-a0712 [relation
between bound systems and global expansion]; Biswas & Notari JCAP(08)ap/07 [swiss
cheese model], et al JCAP(07)
[non-linear structure formation]; Buchert GRG(08)-a0707
[rev]; Ishak et al a0708 [Szekeres
model]; Leith et al ApJ(08)-a0709;
Hossain
a0709 [FRW islands
surrounded by vacuum]; Djorgovskia & Gurzadyan NPPS(07);
Paranjape & Singh a0801;
Wiltshire in(08)-a0712; > s.a. inflation;
Lemaître-Tolman-Bondi; relativistic
cosmology [averaging]; > s.a. Copernican
Principle, Stephani
Model.
@ Not inhomogeneities: Geshnizjani et al PRD(05)ap;
Flanagan PRD(05)ht;
Hirata & Seljak PRD(05)ap;
Rasanen CQG(06)ap/05;
Siegel & Fry ApJL(05)ap;
Ishibashi & Wald CQG(06)gq/05
[general arguments]; Kasai et al PTP(06)ap;
> s.a. observation.
@ Fields: Wigmans ap/02-wd
[
s], ap/04/PRL
[ degeneracy p];
Schwarz ap/02-in
[imperfect CDM]; Novello et al PRD(04)ap/03 [non-linear
electromagnetism]; Holdom JHEP(04)ht [Goldstone
ghost]; Beck ap/05-in
[modified standard model, chaos]; Ribas et al PRD(05)
[fermions]; Rodgers & Yasuda IJMPA(07)ht/06 ["diffeomorphism
scalar field"]; Kehagias ht/06 [non-conventional
scalar]; Bieli ap/06-in
[non-minimal scalar]; Castro FP(07)
[scalar for Weyl invariance].
@ Particle interactions:
Aldrovandi et al gq/05;
Díez-Tejedor & Feinstein PLA(06).
@ Torsion: Wanas a0704-in
[spin-torsion interaction], IJMPA(07)-a0802;
Minkevich et al CQG(07)-a0706 [in
Poincaré gauge theory of gravity].; Shie et al PRD-a0805.
@ Other proposals: Goldberg PLB(00)
[chiral phase transition]; Zimdahl et al PRD(01)ap/00 [anti-friction];
Trentham MNRAS(01)ap [assumptions];
Amendola MNRAS(03)ap/02 [at
z > 1]; Beck PRD(04)ap/03 [chaotic
quantum field theory]; Rendall gq/04-in
[accelerating solutions]; Notari MPLA(06)ap/05 [unjustified
formulation]; Avelino
et al PRD(06)ap [not
cosmic domain wall network]; Oliveira & Hartnett FPL(06)ap [Carmeli's
cosmology]; Bonanno et al CQG(06)
[crossover phenomenon]; Ne'eman IJMPA(06)
["recoil of the mass-making"]; González-Díaz ht/06-in
[subquantum cmb photon potential]; Punzi et al PRD(07)ht/06,
JHEP(07)ht/06 [area
metric cosmology]; Szydlowski & Godlowski IJMPD(08)-a0705 [driven
by Casimir force]; Hammond & Pilling a0806 [gravitating
entropy]; Jiménez & Maroto a0807 [vector field].
> Other models: see
bimetric gravity;
Conformal Gravity; exotic
differentiable structures; fractals in physics; quintessence; tachyons.
Differing Points of View
* Suggestions:
2002, Supernovas may look dimmer because photons turn into axions along the
way.
@ References: Loeb ap/98/ApJL
[deceleration!]; Csáki et al PRL(02)
[axions]; Narlikar et al PASP(02)ap [alternative];
Mészáros ApJ(02)ap [statistical,
premature]; Sawicki ap/02 [R < 0];
Vishwakarma MNRAS(03)ap;
Choudhuri ap/06-in
[Thomson scattering]; Middleditch ap/06 [supernovas,
no acceleration]; Caldwell & Stebbins a0711 [apparent
acceleration from local void]; Arp a0712 [deceleration
and variable particle masses].
Change in Acceleration > s.a. expansion
history.
* 2005: There
is some evidence for oscillations in the Hubble expansion history.
* 2006: There is clear
statistical evidence for a late time transition from a decelerating to an accelerating
phase.
@ Theory: Blandford ap/04-in
[jerk
and
equation of state]; Ponce de León IJMPD(06)gq/05 [model];
Poplawski PLB(06)gq [in f(R)
gravity]; Kim
& Yoon PLB(06)gq [2D
non-commutative dilaton model]; Melchiorri et al PRD(07)-a0706 [beginning
of acceleration].
@ Data: Lazkoz et al JCAP(05)ap [snIa
Gold data set fit]; John ApJ(05)ap,
Elgarøy & Multamäki JCAP(06)ap [past
deceleration, Bayesian analysis]; Ishida et al a0706 [beginning
of acceleration]; Daly et al a0710.
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23 jul 2008