Brans–Dicke Gravity with a Cosmological Constant Smoothes Out ΛCDM Tensions

Peracaula, Joan Solà; Gómez-Valent, Adrià; Pérez, Javier de Cruz; Moreno-Pulido, Cristian

doi:10.3847/2041-8213/ab53e9

Cited by 132 publications

(151 citation statements)

References 475 publications

Supporting

Mentioning

140

Contrasting

Order By: Relevance

“…On the other hand, despite the fact that the ΛCDM model is found to be in a very good agreement with the majority of cosmological data [7], nonetheless the model seems to be currently in tension with some recent measurements [32][33][34][35], related with the Hubble constant H 0 and the present value of the mass variance at 8h −1 Mpc, namely σ 8 . Moreover, Lusso et al [1] using a combined Hubble diagram of SNIa, Quasars, and gamma-ray bursts (GRBs) found a ∼ 4σ tension between the best fit cosmographic parameters with respect to those of ΛCDM (see also [2,36]).…”

Section: Introductionmentioning

confidence: 82%

Does $$\varLambda $$CDM really be in tension with the Hubble diagram data?

Mehrabi

Basilakos

2020

Eur. Phys. J. C

View full text Add to dashboard Cite

In this article, we elaborate further on the $$\varLambda $$ Λ CDM “tension”, suggested recently by the authors Lusso et al. (Astron Astrophys 628:L4, 2019) and Risaliti and Lusso (Nat Astron 3(3):272, 2019). We combine Supernovae type Ia (SNIa) with quasars (QSO) and Gamma Ray Bursts (GRB) data in order to reconstruct in a model independent way the Hubble relation to as high redshifts as possible. Specifically, in the case of either SNIa or SNIa/QSO data we find that the current values of the cosmokinetic parameters extracted from the Gaussian process are consistent with those of $$\varLambda $$ Λ CDM. Including GRBs in the analysis we find a tension, which lies between $$2\sigma $$ 2 σ and $$3\sigma $$ 3 σ levels respectively. Finally, we find that at high redshifts ($$z>1$$ z > 1 ) the corresponding cosmokinetic parameters significantly deviate from those of $$\varLambda $$ Λ CDM, hence the possibility of new Physics is not precluded by the present analysis.

show abstract

Section: Introductionmentioning

confidence: 82%

Does $$\varLambda $$CDM really be in tension with the Hubble diagram data?

Mehrabi

Basilakos

2020

Eur. Phys. J. C

View full text Add to dashboard Cite

show abstract

“…As it has been shown in the literature, models mimicking a time-evolving (and hence a dynamical vacuum energy density ρ ) could help in alleviating these problems, see e.g. [16][17][18][19][20][21][22][23][24][25][26][27] and [28][29][30][31][32][33][34][35][36][37][38][39][40].…”

Section: Introductionmentioning

confidence: 99%

Running vacuum in quantum field theory in curved spacetime: renormalizing $$\rho _{vac}$$ without $$\sim m^4$$ terms

2020

Self Cite

View full text Add to dashboard Cite

The $$\Lambda $$Λ-term in Einstein’s equations is a fundamental building block of the ‘concordance’ $$\Lambda $$ΛCDM model of cosmology. Even though the model is not free of fundamental problems, they have not been circumvented by any alternative dark energy proposal either. Here we stick to the $$\Lambda $$Λ-term, but we contend that it can be a ‘running quantity’ in quantum field theory (QFT) in curved space time. A plethora of phenomenological works have shown that this option can be highly competitive with the $$\Lambda $$ΛCDM with a rigid cosmological term. The, so-called, ‘running vacuum models’ (RVM’s) are characterized by the vacuum energy density, $$\rho _{vac}$$ρvac, being a series of (even) powers of the Hubble parameter and its time derivatives. Such theoretical form has been motivated by general renormalization group arguments, which look plausible. Here we dwell further upon the origin of the RVM structure within QFT in FLRW spacetime. We compute the renormalized energy-momentum tensor with the help of the adiabatic regularization procedure and find that it leads essentially to the RVM form. This means that $$\rho _{vac}(H)$$ρvac(H) evolves as a constant term plus dynamical components $${{\mathcal {O}}}(H^2)$$O(H2) and $$\mathcal{O}(H^4)$$O(H4), the latter being relevant for the early universe only. However, the renormalized $$\rho _{vac}(H)$$ρvac(H) does not carry dangerous terms proportional to the quartic power of the masses ($$\sim m^4$$∼m4) of the fields, these terms being a well-known source of exceedingly large contributions. At present, $$\rho _{vac}(H)$$ρvac(H) is dominated by the additive constant term accompanied by a mild dynamical component $$\sim \nu H^2$$∼νH2 ($$|\nu |\ll 1$$|ν|≪1), which mimics quintessence.

show abstract

“…GeV is the reduced Planck mass, and n is taken as an even and positive integer, to reduce the H 0 tension. This simple model relies on the degeneracy between a nonminimal coupling to the Ricci curvature and the Hubble parameter which has been studied in previous works on the constraints on scalar-tensor theories of gravity 2 [35][36][37][38]. In general, scalar-tensor models modify both the early (in a way that resembles a contribution of an extra dark radiation component) and late-time expansion of the Universe [37].…”

Section: Introductionmentioning

confidence: 99%

Larger value for H0 by an evolving gravitational constant

et al. 2020

View full text Add to dashboard Cite

We provide further evidence that a massless cosmological scalar field with a nonminimal coupling to the Ricci curvature of the type M 2 pl ð1 þ ξσ n =M n pl Þ alleviates the existing tension between local measurements of the Hubble constant and its inference from cosmic microwave background anisotropies and baryonic acoustic oscillations data in the presence of a cosmological constant. In these models, the expansion history is modified compared to ΛCDM at early time, mimicking a change in the effective number of relativistic species, and gravity weakens after matter-radiation equality. Compared to ΛCDM, a quadratic (n ¼ 2) coupling increases the Hubble constant when Planck 2018 (alone or in combination with BAO and SH0ES) measurements data are used in the analysis. Negative values of the coupling, for which the scalar field decreases, seem favored and consistency with the Solar System can be naturally achieved for a large portion of the parameter space without the need of any screening mechanism. We show that our results are robust to the choice of n, also presenting the analysis for n ¼ 4.

show abstract

Brans–Dicke Gravity with a Cosmological Constant Smoothes Out ΛCDM Tensions

Cited by 132 publications

References 475 publications

Does $$\varLambda $$CDM really be in tension with the Hubble diagram data?

Does $$\varLambda $$CDM really be in tension with the Hubble diagram data?

Running vacuum in quantum field theory in curved spacetime: renormalizing $$\rho _{vac}$$ without $$\sim m^4$$ terms

Larger value for H0 by an evolving gravitational constant

Contact Info

Product

Resources

About