The possible role of elementary particle physics in cosmology

Omnès, Roland

doi:10.1016/0370-1573(72)90009-9

Cited by 71 publications

(7 citation statements)

References 76 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since we can only calculate the element abundances at discrete values of φ, we divide the range in φ into logarithmic bins and change the integrals in Eqs. (13) and (14) into the corresponding sums:…”

Section: Standard Bbnmentioning

confidence: 99%

“…Whenever this quantity is convex, Jensen's inequality applied to Eq. (14) implies that R > 1, i.e., the effect of inhomogeneities is to increase the deuterium and 7 Li abundances relative to their homogeneous abundances. Furthermore, this result is independent of the functional form for f (φ) as long as f (φ) is small outside the range where X A (φ)φ is convex.…”

Section: Standard Bbnmentioning

confidence: 99%

See 1 more Smart Citation

Constraining density fluctuations with big bang nucleosynthesis in the era of precision cosmology

Barrow

Scherrer

2018

Phys. Rev. D

View full text Add to dashboard Cite

We reexamine big bang nucleosynthesis with large-scale baryon density inhomogeneities when the length scale of the density fluctuations exceeds the neutron diffusion length (∼ 10 7 −10 8 cm at BBN), and the amplitude of the fluctuations is sufficiently small to prevent gravitational collapse. In this limit, the final light element abundances can be determined by simply mixing the abundances from regions with different baryon/photon ratios without interactions. We examine gaussian, lognormal, and gamma distributions for the baryon/photon ratio, η. We find that the deuterium and lithium-7 abundances increase with the RMS fluctuation in η, while the effect on helium-4 is much smaller. We show that these increases in the deuterium and lithium-7 abundances are a consequence of Jensen's inequality, and we derive analytic approximations for these abundances in the limit of small RMS fluctuations. Observational upper limits on the primordial deuterium abundance constrain the RMS fluctuation in η to be less than 17% of the mean value of η. This provides us with a new limit on the graininess of the early universe.

show abstract

Section: Standard Bbnmentioning

confidence: 99%

Section: Standard Bbnmentioning

confidence: 99%

Constraining density fluctuations with big bang nucleosynthesis in the era of precision cosmology

Barrow

Scherrer

2018

Phys. Rev. D

View full text Add to dashboard Cite

show abstract

“…It features a symmetric matter-antimatter universe, where matter and antimatter effectively repel each other, but where antimatter also repels itself. As is well-known, when the usual expression of the weak equivalence principle is respected for matter and antimatter, such symmetric matter-antimatter cosmologies are excluded by the non observation of a diffuse gamma-ray flux (Omnès 1972;Cohen et al 1998). On the other hand, the D-M cosmology is a gravitational implementation of the Dirac particle-hole sea, analogous to the electron-hole system in a semiconductor.…”

Section: The Dirac-milne Universementioning

confidence: 99%

MOND-like behavior in the Dirac–Milne universe

Chardin

Dubois

Manfredi

et al. 2021

A&A

View full text Add to dashboard Cite

Aims. Observational data show that the observed luminous matter is not sufficient to explain several features of the present universe, from gravitational structure formation to the rotational velocities in galaxies and clusters. The mainstream explanation is that the missing mass, although gravitationally active, interacts very weakly with ordinary matter. Competing explanations involve changing the laws of gravity at low accelerations, as in MOdified Newtonian Dynamics (MOND). Here, we suggest that the Dirac-Milne cosmology, a matter-antimatter symmetric cosmology where the two components repel each other, is capable of accounting for such an apparent modification of the Newtonian law, without invoking dark matter. Methods. Using a simple analytical approximation and 1D and 3D simulations, we study rotation curves and virial velocities and compare the mass observed in the simulations to the mass derived assuming Newtonian gravity. Using a modified version of the RAMSES code, we study the Faber-Jackson scaling relation and the intensity of the additional gravitational field created by antimatter clouds. Results. We show that, in the Dirac-Milne universe, rotation curves are generically flat beyond a characteristic distance of ≈2.5 virial radii, and that the Tully-Fisher and Faber-Jackson scaling relations with an exponent ≈3 are satisfied. We show that the mass derived from the rotation curves assuming Newtonian gravity is systematically overestimated compared to the mass really present. In addition, the Dirac-Milne universe, featuring a polarization between its matter and antimatter components, presents a behavior similar to that of MOND, characterized by an additional surface gravity compared to the Newtonian case. We show that in the Dirac-Milne universe, at the present epoch, the intensity of the additional gravitational field gam due to the presence of clouds of antimatter is on the order of a few 10−11 m s−2, similar to the characteristic acceleration of MOND. We study the evolution of this additional acceleration gam and show that it depends on the redshift, and it is therefore not a fundamental constant. Conclusions. Combined with its known concordance properties on the SNIa luminosity distance, age, nucleosynthesis, and structure formation, the Dirac-Milne cosmology may then represent an interesting alternative to the standard cosmological model ΛCDM, MOND, and other scenarios for explaining the dark matter (or missing gravity) and dark energy conundrum.

show abstract

“…It features a symmetric matter-antimatter universe, where matter and antimatter effectively repel each other, but where antimatter also repels itself. As is well-known, when the usual expression of the Equivalence Principle is respected for matter and antimatter, such symmetric matter-antimatter cosmologies are excluded by the nonobservation of a diffuse gamma-ray flux (Omnès 1972;Cohen et al 1998). On the other hand, the Dirac-Milne cosmology is a gravitational implementation of the Dirac particle-hole sea, analog to the electron-hole system in a semiconductor.…”

Section: Dirac-milne Universementioning

confidence: 99%

MOND-like behavior in the Dirac-Milne universe -- Flat rotation curves and mass/velocity relations in galaxies and clusters

Chardin,

Dubois,

Manfredi

et al. 2021

Preprint

View full text Add to dashboard Cite

Aims. Observational data suggest that the observed luminous matter is not sufficient to explain several features of the present universe, from gravitational structure formation to the rotational velocities in galaxies and clusters. The mainstream explanation is that the missing mass, although gravitationally active, interacts very weakly with ordinary matter. Competing explanations involve changing the laws of gravity at low accelerations, as in MOND (Modified Newtonian Dynamics). Here, we suggest that the Dirac-Milne cosmology, a matter-antimatter symmetric cosmology where the two components repel each other, is capable of accounting for such apparent modification of the Newtonian law, without invoking dark matter. Methods. Using a simple analytical approximation and 1D and 3D simulations, we study rotation curves and virial velocities, and compare the mass observed in the simulations to the mass derived assuming Newtonian gravity. Using a modified version of the RAMSES code, we study the Faber-Jackson scaling relation and the intensity of the additional gravitational field created by antimatter clouds.Results. We show that, in the Dirac-Milne universe, rotation curves are generically flat beyond the characteristic distance of ≈ 2.5 virial radii and that the Tully-Fisher and Faber-Jackson scaling relations with exponent ≈ 3 are satisfied. We show that the mass derived from the rotation curves assuming Newtonian gravity is systematically overestimated compared to the mass really present. In addition, the Dirac-Milne universe, featuring a polarization between its matter and antimatter components, presents a behavior similar to that of MOND, characterized by an additional surface gravity compared to the Newtonian case. We show that in the Dirac-Milne universe, at the present epoch, the intensity of the additional gravitational field g am due to the presence of clouds of antimatter is of the order of a few 10 −11 m/s 2 , similar to the characteristic acceleration of MOND. We study the evolution of this additional acceleration g am and show that it depends on the redshift, and is therefore not a fundamental constant. Conclusions. Combined with its known concordance properties on SNIa luminosity distance, age, nucleosynthesis and structure formation, the Dirac-Milne cosmology may then represent an interesting alternative to the ΛCDM , MOND, and other scenarios for explaining the Dark Matter and Dark Energy conundrum.

show abstract

The possible role of elementary particle physics in cosmology

Cited by 71 publications

References 76 publications

Constraining density fluctuations with big bang nucleosynthesis in the era of precision cosmology

Constraining density fluctuations with big bang nucleosynthesis in the era of precision cosmology

MOND-like behavior in the Dirac–Milne universe

MOND-like behavior in the Dirac-Milne universe -- Flat rotation curves and mass/velocity relations in galaxies and clusters

Contact Info

Product

Resources

About