Conformal Gravity Solutions to Standard Gravity Problems

O’Brien, James; Chaykov, Spasen; Chiarelli, Thomas L.; Saintable, Taylor; Harrington, Justin

doi:10.1142/s2010194517600035

Cited by 2 publications

(2 citation statements)

References 10 publications

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“…In the past, attempts have been made to explain galactic rotation curve data without the addition of a dark matter halo in this model [99], and furthermore, refs. [100,101] also address observed galaxy cluster motion with no dark matter. Furthermore, if CG is to account for all dark matter in the Universe, it is so far unclear if it can pass gravitational lensing tests [102][103][104][105][106][107][108], and inconsistencies with gravitational wave observation of binaries have been found [109].…”

Section: Conformal Gravity Cosmologymentioning

confidence: 98%

Probing alternative cosmologies through the inverse distance ladder

Lindner

Max²,

Platscher

et al. 2020

J. Cosmol. Astropart. Phys.

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We study the implications of a combined analysis of cosmic standard candles and standard rulers on the viability of cosmological models beyond the cosmological concordance model ΛCDM. To this end, we employ well-established data in the form of the joint lightcurve analysis supernova compilation, baryon acoustic oscillations, and cosmic microwave background data on the one hand, and a recently proposed set of quasars as objects of known brightness on the other hand. The advantage of including the latter is that they extend the local distance measures to redshifts which have previously been out of reach and we investigate how this allows one to test cosmologies beyond ΛCDM. While there exist various studies on parametric extensions of ΛCDM, we present here a comparative study of both parametric and fundamental extensions of the standard cosmology. In order to keep the scope of this manuscript contained, we focus on two particular modifications: one is the consistent theory of two interacting spin-2 objects, so-called bigravity, and the other conformal gravity, a theory of gravity that has no knowledge of fundamental length scales. The former of the two constitutes a veritable extension of General Relativity, given that it adds to the metric tensor of gravity a second dynamical tensor field. The resulting dynamics have been proposed as a self-accelerating cosmology. Conformal gravity on the other hand is a much more drastic change of the underlying gravitational theory. Its ignorance towards fundamental length scales offers a completely different approach to the origin of late time acceleration. In this sense, both models offer -in one way or another --an explanation for the dark energy problem. We perform a combined cosmological fit which provides strong constraints on these extensions. We also briefly comment on the implications of the longstanding H 0 -tension.

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Section: Conformal Gravity Cosmologymentioning

confidence: 98%

Probing alternative cosmologies through the inverse distance ladder

Lindner

Max²,

Platscher

et al. 2020

J. Cosmol. Astropart. Phys.

View full text Add to dashboard Cite

show abstract

“…In the past, attempts have been made to explain galactic rotation curve data without the addition of a dark matter halo in this model [78], and furthermore, Refs. [79,80] also address observed galaxy cluster motion with no dark matter. Furthermore, if CG is to account for all dark matter in the universe, it is so far unclear if it can pass gravitational lensing tests [81][82][83][84][85][86][87] and inconsistency with gravitational wave observation of binaries have been found in Ref.…”

Section: Conformal Gravity Cosmologymentioning

confidence: 98%

Probing alternative cosmologies through the inverse distance ladder

Lindner,

Max,

Platscher

et al. 2020

Preprint

View full text Add to dashboard Cite

We study the implications of a combined analysis of cosmic standard candles and standard rulers on the viability of cosmological models beyond the cosmological concordance model ΛCDM. To this end, we employ well-established data in the form of the joint lightcurve analysis supernova compilation, baryon acoustic oscillations, and cosmic microwave background data on the one hand, and a recently proposed set of Quasars as objects of known brightness on the other hand. The advantage of including the latter is that they extend the local distance measures to redshifts which have previously been out of reach and we investigate how this allows one to test cosmologies beyond ΛCDM. While there exist various studies on parametric extensions of ΛCDM, we present here a comparative study of both parametric and fundamental extensions of the standard cosmology. In order to keep the scope of this manuscript contained, we focus on two particular modifications: One is the theory of a massive tensor field interacting with the standard metric of gravity, so-called bigravity, and the other conformal gravity, a theory of gravity that has no knowledge of fundamental length scales. The former of the two constitutes a veritable extension of General Relativity, given that it adds to the metric tensor of gravity a second dynamical tensor field. The resulting dynamics have been proposed as a self-accelerating cosmology. Conformal gravity on the other hand is a much more drastic change of the underlying gravitational theory. Its ignorance towards fundamental length scales offers a completely different approach to late time acceleration and the so-called cosmological constant problem. In this sense, both models offer -in one way or another -an explanation for the cosmological constant problem. We perform a combined cosmological fit which provides strong constraints on some of these extensions, while some alternative cosmologies are in fact favoured by the data. We also briefly comment on the implications of the long-standing H 0 -tension.

show abstract

Conformal Gravity Solutions to Standard Gravity Problems

Cited by 2 publications

References 10 publications

Probing alternative cosmologies through the inverse distance ladder

Probing alternative cosmologies through the inverse distance ladder

Probing alternative cosmologies through the inverse distance ladder

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