Cosmological Expansion Rate – Issues and Effects| Cosmological Expansion Rate – Issues and Effects |
Global-Local Discrepancy
> s.a. acceleration [variation in time]; expansion rate;
friedmann equation.
* Status: 2013, There is a 9% discrepancy
between the value for H0 obtained indirectly
from global measurements of the cosmic microwave background and baryon acoustic oscillations,
\(H_0\) = 67.8 ± 0.9 km/s·Mpc, and the one obtained more directly from local
measurements of the relation between redshifts and distances to sources, \(H_0\) = 73.8
± 2.4 km/s·Mpc; Only part of this seems to be attributable to a cosmic
variance of the Hubble parameter.
@ General references: Marra et al PRL(13)-a1303 [and errors];
Verde et al a1306/PDU [quantifying the tension];
Spergel et al PRD(15)-a1312;
Bernal et al JCAP(16)-a1607 [comprehensive analysis];
Baryshev a1610-in;
Feeney et al MNRAS(18)-a1707 [Bayesian hierarchical model];
news sn(18)jan [the discrepancy remains];
Macpherson et al ApJL(18)-a1807 [in inhomogeneous numerical simulations];
Ryan et al MNRAS(19)-a1902 [and dark energy];
Jeong & Kamionkowski PRL(20)-a1908;
Del Valle Mazo & Romano a1912;
Pérez et al GRG(21)-a2001 [solution from diffusion];
Di Valentino et al a2103 [rev].
@ Observations: video NASA(17)sep;
news cosmos(18)mar,
sn(18)mar;
cosmos(19)feb [using neutron stars to resolve it];
news sn(19)jul [update];
Ding et al a1912 [and Gpc-scale local void];
news pt(20)feb,
PT(20)mar [past the 5-σ level];
Vagnozzi et al a2105
[ages of the oldest astrophysical objects].
@ Explanations and related topics: Li et al SCG-a1311;
Romano & Vallejo EPL(15)-a1403 [local overdensity?];
Clarkson et al JCAP(14)-a1405 [relativistic corrections remove the tension];
Odderskov et al JCAP(16)-a1601 [inhomogeneities not likely to be the reason];
Bengaly JCAP(16)-a1510 [effect of the bulk flow motion];
Di Valentino et al PLB(16)-a1606 [extended parameter space, with a phantom-like dark-energy component];
Romano IJMPD(18)-a1609;
news sn(17)jun [local void];
Di Valentino et al PRD(18)-a1710 [vacuum phase transition];
Bolejko PRD(18)-a1712 [spatial curvature];
Poulin et al PRL(19) [early dark energy];
Kasai & Futamase a1904 [and spatial averaging];
Krishnan et al PRD(20)-a2002 [on early-Universe solutions];
Capozziello et al FP(20)-a2007 [uncertainty in kinematic-dynamical relation];
Mörtsell et al a2105 [Cepheid color calibration].
Isotropy and Spatial Variation of H
> s.a. acceleration [variation in time]; friedmann equation.
@ General references: Wiltshire et al PRD(13)-a1201 [and the cmb dipole].
@ Homogeneity: Giovanelli et al ApJ(99)ap [support];
Enqvist & Mattsson JCAP(07) [inhomogeneity and supernova observations];
Ben-Dayan et al PRL(14)-a1401 [effect of inhomogeneities on measurements
of H0, fully relativistic treatment];
> s.a. galaxies.
@ Isotropy:
Bochner ap/07-TX [mild evidence for anisotropy];
McClure & Dyer NA(07)ap [statistically significant difference of 9 km/s/Mpc seen];
Schwarz & Weinhorst A&A(07)-a0706 [statistically significant N/S difference at z < 0.2];
Quercellini et al PRL(09) [with future missions];
Campanelli PRD(11),
Kalus et al A&A(13)-a1212,
Cai et al PRD(13),
Beltrán et al PLB(14)-a1402 [constraints on anisotropy from supernovae];
Bolejko et al JCAP(16)-a1512 [statistically significant evidence for anisotropy];
Migkas & Plionis RMAA-a1602 [outliers, but no significant evidence for anisotropy];
Soltis et al PRL(19)-a1902 [expansion rates agree to better than 1%];
> s.a. cmb anisotropy.
@ Vorticity and shear:
Jaffe et al ApJL(05)ap;
Palle ap/05 [results not reliable];
Marozzi & Uzan PRD(12)-a1206 [shear from backreaction, and anisotropy of expansion];
> s.a. cosmological tests of gravity.
Theoretical Effects > s.a. early-universe models [bounce];
gravitational-wave background; Phantom Divide.
* With dark energy: If it
is modeled as a perfect fluid with equation of state parameter w
> −1, one gets \(a(t) = a_0^{~} (t/t_0^{~})^{2/3(1+w)}\).
* Effect of inhomogeneities: If
the length scale at which homogeneity sets in is much smaller than the Hubble
length scale, the back-reaction on the expansion rate due to averaging over
inhomogeneities is negligible.
@ General references:
Sandage & Lubin AJ(01),
Lubin & Sandage AJ(01)ap,
AJ(01)ap,
AJ(01) [Tolman surface brightness test];
Abramo & Woodard PRD(02)ap/01 [covariant];
Carroll & Kaplinghat PRD(02) [during nucleosynthesis];
Wei & Zhang PLB(07)ap/06 [and various models];
Shafieloo MNRAS(07)ap [reconstruction];
Sen & Scherrer PLB(08)ap/07 [and weak energy condition];
Cherkas & Kalashnikov NPCS-a1206 [local variations on the scale factor].
@ Effect of inhomogeneities:
Geshnizjani & Brandenberger PRD(02)gq;
Kozaki & Nakao PRD(02)gq [swiss-cheese model];
Kolb et al PRD(05)hp/04;
Lieu ap/05/ApJL;
Zhao & Mathews PRD(11)-a0912 [and structure formation, numerical];
Collins a1011 [theoretical model];
Singh a1105-proc;
Tsamis & Woodard a1405 [back-reaction];
Adamek et al PRL(15)-a1408 [backreaction is a small effect];
Romano & Vallejo EPJC(16)-a1502 [local structure];
Tsagas & Kadiltzoglou PRD(15)-a1507
[effect of peculiar motions on measurements of the deceleration parameter];
Roukema et al A&A(17)-a1608 [background Hubble constant];
Peñarrubia & Fattahi MNRAS(17)-a1609;
Fleury et al JCAP(17)-a1612 [large-scale structure];
Basu et al JHEP(17)-a1612 [super-horizon gravitons and the expansion rate];
> s.a. effect of inhomogeneities on acceleration.
@ Local effects of the expansion: Ohanian AJP(00)aug;
Bolen et al CQG(01)gq/00;
Davis et al AJP(03)apr-ap/01 [red-/blueshift];
Domínguez & Gaite EPL(01)ap;
Price & Romano AJP(12)may-gq/05 [classical atom];
Carrera & Giulini gq/06;
Adkins et al PRD(07)gq/06;
Sereno & Jetzer PRD(07)ap [with dark matter and dark energy];
Balaguera-Antolínez & Nowakowski CQG(07)-a0704 [on large-scale structure];
Faraoni & Jacques PRD(07)-a0707;
Nandra et al MNRAS(12)-a1104,
MNRAS(12)-a1104;
Castelo Ferreira AAM(14)-a1203 [corrections to planetary motion];
Giulini SHPMP(14)-a1306-proc;
Arenas a1309;
Iorio Gal(14)-a1312 [with acceleration, orbit expansion];
Kopeikin EPJP(15)-a1407-conf;
Widom et al a1507-MG14 [tests of local expansion–within the galaxy];
Dumin a1609-proc [overview];
Wiens et al PRL(16) [rulers and atomic clocks];
Rothman et al PRD(19)-a1808 [holonomy in the McVittie spacetime];
Antoniou et al CQG(19)-a1903 [spinning particles];
Pons & Talavera a2011;
> s.a. cosmology in general relativity;
Rigid Body.
@ And structure formation:
Wetterich PRD(03);
Räsänen JCAP(08)-a0801,
IJMPD(08)-a0805-GRF.
Other Effects and Theories
Overall expansion: see cosmological expansion;
friedmann equation.
Effect of perturbations: see averaging in
cosmology; effect on acceleration; cosmological
perturbations.
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