Who discovered Universe expansion?

Steer, Ian

doi:10.48550/arxiv.1212.1359

Cited by 2 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Returning to the historical picture, during the 1920s, observational and theoretical evidence started to accumulate, suggesting that the Universe was not static [56,57]. Many authors began to consider this possibility as realistic.…”

Section: The Beginning Of Relativistic Cosmologymentioning

confidence: 99%

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

Peracaula

Gómez-Valent

Pérez

et al. 2019

ApJL

127

138

View full text Add to dashboard Cite

We analyze Brans-Dicke gravity with a cosmological constant, Λ, and cold dark matter (BD-ΛCDM for short) in the light of the latest cosmological observations on distant supernovae, Hubble rate measurements at different redshifts, baryonic acoustic oscillations, large scale structure formation data, gravitational weak-lensing and the cosmic microwave background under full Planck 2015 CMB likelihood. Our analysis includes both the background and perturbations equations. We find that BD-ΛCDM is observationally favored as compared to the concordance ΛCDM model, which is traditionally defined within General Relativity (GR). In particular, some well-known persisting tensions of the ΛCDM with the data, such as the excess in the mass fluctuation amplitude σ 8 and specially the acute H 0 -tension with the local measurements, essentially disappear in this context. Furthermore, viewed from the GR standpoint, BD-ΛCDM cosmology mimics quintessence at 3σ c.l. near our time.

show abstract

Section: The Beginning Of Relativistic Cosmologymentioning

confidence: 99%

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

Peracaula

Gómez-Valent

Pérez

et al. 2019

ApJL

127

138

View full text Add to dashboard Cite

show abstract

“…On the other hand, in 1922, Friedman found solutions of equations of GR with Λ = 0 to provide theoretical evidence that the universe is expanding [19]. The author of [20] states that Lundmark was the first person to find observational evidence for expansion in 1924-three years before Lemaître and five years before Hubble, but, for some reasons, Lundmark's research was not adopted and his paper was not published. In 1927, Lemaître independently reached a similar conclusion to Friedman on a theoretical basis, and also presented observational evidence (based on the Doppler effect) for a linear relationship between distance to galaxies and their recessional velocity [21].…”

Section: History Of Dark Energymentioning

confidence: 99%

Solving Particle–Antiparticle and Cosmological Constant Problems

Lev

2024

Axioms

View full text Add to dashboard Cite

We solve the particle-antiparticle and cosmological constant problems proceeding from quantum theory, which postulates that: various states of the system under consideration are elements of a Hilbert space H with a positive definite metric; each physical quantity is defined by a self-adjoint operator in H; symmetry at the quantum level is defined by a representation of a real Lie algebra A in H such that the representation operator of any basis element of A is self-adjoint. These conditions guarantee the probabilistic interpretation of quantum theory. We explain that in the approaches to solving these problems that are described in the literature, not all of these conditions have been met. We argue that fundamental objects in particle theory are not elementary particles and antiparticles but objects described by irreducible representations (IRs) of the de Sitter (dS) algebra. One might ask why, then, experimental data give the impression that particles and antiparticles are fundamental and there are conserved additive quantum numbers (electric charge, baryon quantum number and others). The reason is that, at the present stage of the universe, the contraction parameter R from the dS to the Poincare algebra is very large and, in the formal limit R→∞, one IR of the dS algebra splits into two IRs of the Poincare algebra corresponding to a particle and its antiparticle with the same masses. The problem of why the quantities (c,ℏ,R) are as are does not arise because they are contraction parameters for transitions from more general Lie algebras to less general ones. Then the baryon asymmetry of the universe problem does not arise. At the present stage of the universe, the phenomenon of cosmological acceleration (PCA) is described without uncertainties as an inevitable kinematical consequence of quantum theory in semiclassical approximation. In particular, it is not necessary to involve dark energy the physical meaning of which is a mystery. In our approach, background space and its geometry are not used and R has nothing to do with the radius of dS space. In semiclassical approximation, the results for the PCA are the same as in General Relativity if Λ=3/R2, i.e., Λ>0 and there is no freedom for choosing the value of Λ.

show abstract

Who discovered Universe expansion?

Cited by 2 publications

References 0 publications

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

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

Solving Particle–Antiparticle and Cosmological Constant Problems

Contact Info

Product

Resources

About