Cosmological $Λ$ driven inflation and produced massive particles

Xue, She‐Sheng

doi:10.48550/arxiv.1910.03938

Cited by 3 publications

(6 citation statements)

References 2 publications

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“…The ω H M ≈ 0 for m H slow and its upper limit is 1/3. The introduced mass parameter m represents possible particle masses M f , degeneracies g [30,31].…”

Section: Massive Pair Plasma Statementioning

confidence: 99%

“…For Fig. 2 and calculations below, we chose the reference value χ ∼ 10 −3 at the same order of χ ≈ 1.85 × 10 −3 that we approximately obtained for massive fermion pair productions in an exact De Sitter spacetime [30,31].…”

Section: Inflation and Tensor-to-scalar Ratiomentioning

confidence: 99%

“…To properly include the back-reaction of particle production on Universe evolution, one should separate fast components O(1/M) from slow components O(1/H ) in the Friedman equation. Many efforts [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] have been made to study non-adiabatic backreaction and understand massive particle productions without exponential suppression. It is important for reheating, possibly accounting for massive dark matter and total entropy of the present Universe [15,16,.…”

Section: Introductionmentioning

confidence: 99%

“…Discussions can be applied for fermion fields. Analogously, we discussed the back and forth processes of massive fermion and antifermion pairs production and annihilation in spacetime S ⇔ F + F in Refs [30,31,53]…”

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confidence: 99%

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Massive particle pair production and oscillation in Friedman Universe: its effect on inflation

Xue

2023

Eur. Phys. J. C

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We study the classical Friedman equations for the time-varying cosmological term $$\tilde{\Lambda }$$ Λ ~ and Hubble function H, together with quantised field equations for the production of massive $$M\gg H$$ M ≫ H particles, namely, the $$\tilde{\Lambda }$$ Λ ~ CDM scenario of dark energy and matter interactions. Classical slow components $${\mathcal O}(H^{-1})$$ O ( H - 1 ) are separated from quantum fast components $${\mathcal O}(M^{-1})$$ O ( M - 1 ) . The former obeys the Friedman equations, and the latter obeys a set of nonlinear differential equations. Numerically solving equations for quantum fast components, we find the production and oscillation of massive particle-antiparticle pairs in microscopic time scale $${\mathcal O}(M^{-1})$$ O ( M - 1 ) . Their density and pressure averages over microscopic time do not vanish. It implies the formation of a massive pair plasma state in macroscopic time scale $${\mathcal O}(H^{-1})$$ O ( H - 1 ) , whose effective density and pressure contribute to the Friedman equations. Considering the inflation driven by the time-varying cosmological term and slowed down by the massive pair plasma state, we obtain the relation of spectral index and tensor-to-scalar ratio in agreement with recent observations. We discuss the singularity-free pre-inflation, the CMB large-scale anomaly, and dark-matter density perturbations imprinting on power spectra.

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“…The ω H M ≈ 0 for m H slow and its upper limit is 1/3. The introduced mass parameter m represents possible particle masses M f , degeneracies g [30,31].…”

Section: Massive Pair Plasma Statementioning

confidence: 99%

Section: Inflation and Tensor-to-scalar Ratiomentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Massive particle pair production and oscillation in Friedman Universe: its effect on inflation

Xue

2023

Eur. Phys. J. C

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“…Notwithstanding the absence of the detailed and explicit interpretation of such a modelling E(z), we are in the position of providing some insights into possible physics. The parameters δ G and δ Λ effectively represent the possible physical effects or combinations of these effects in addition to those of the ΛCDM model, such as: small time-varying gravitational constant G and inhomogeneity of matter distribution in different redshift z; the JCAP07(2021)005 transition from the radiation-dominated era to the matter-dominated era, and vice versa, depending on species of normal particles or dark matter particles; and massive particle production and annihilation due to the interaction between dark energy (vacuum energy) and other cosmological components [47,48]. δ G > 0 or δ G < 0 implies that the decrease of ρ m,r is slower or faster than that of ΛCDM.…”

Section: Motivation and Cosmological Modelsmentioning

confidence: 99%

Relieving the H₀tension with a new interacting dark energy model

Gao

Zhao

Xue

et al. 2021

J. Cosmol. Astropart. Phys.

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We investigate an extended cosmological model motivated by the asymptotic safety of gravitational field theory, in which the matter and radiation densities and the cosmological constant receive a correction parametrized by the parameters δ G and δ Λ , leading to that both the evolutions of the matter and radiation densities and the cosmological constant slightly deviate from the standard forms. Here we explain this model as a scenario of vacuum energy interacting with matter and radiation. We consider two cases of the model: (i) Λ̃CDM with one additional free parameter δ G , with δ G and δ Λ related by a low-redshift limit relation and (ii) eΛ̃CDM with two additional free parameters δ G and δ Λ that are independent of each other. We use two data combinations, CMB+BAO+SN (CBS) and CMB+BAO+SN+H 0 (CBSH), to constrain the models. We find that, in the case of using the CBS data, neither Λ̃CDM nor eΛ̃CDM can effectively alleviate the H 0 tension. However, it is found that using the CBSH data the H 0 tension can be greatly relieved by the models. In particular, in the case of eΛ̃CDM, the H 0 tension can be resolved to 0.71σ. We conclude that as an interacting dark energy model, Λ̃CDM is much better than Λ(t)CDM in the sense of both relieving the H 0 tension and fitting to the current observational data.

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Holographic massive plasma state in Friedman universe: cosmological fine-tuning and coincidence problems

Xue 生

2024

J. Cosmol. Astropart. Phys.

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Massive particle and antiparticle pair production and oscillation on the horizon form a holographic and massive pair plasma state in the Friedman Universe. Via this state, the Einstein cosmology term (dark energy) interacts with matter and radiation and is time-varying Λ̃ in the Universe's evolution. It is determined by a close set of ordinary differential equations for dark energy, matter, and radiation energy densities. The solutions are unique, provided the initial conditions given by observations. In inflation and reheating, dark energy density decreases from the inflation scale, converting to matter and radiation energy densities. In standard cosmology, matter and radiation energy densities convert to dark energy density, reaching the present Universe. By comparing with ΛCDM, quintessence and dark energy interacting models, we show that these results can be the possible solutions for cosmological fine-tuning and coincidence problems.

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Cosmological $Λ$ driven inflation and produced massive particles

Cited by 3 publications

References 2 publications

Massive particle pair production and oscillation in Friedman Universe: its effect on inflation

Massive particle pair production and oscillation in Friedman Universe: its effect on inflation

Relieving the H₀tension with a new interacting dark energy model

Holographic massive plasma state in Friedman universe: cosmological fine-tuning and coincidence problems

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Cosmological $Λ$ driven inflation and produced massive particles

Cited by 3 publications

References 2 publications

Massive particle pair production and oscillation in Friedman Universe: its effect on inflation

Massive particle pair production and oscillation in Friedman Universe: its effect on inflation

Relieving the H0tension with a new interacting dark energy model

Holographic massive plasma state in Friedman universe: cosmological fine-tuning and coincidence problems

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Product

Resources

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Relieving the H₀tension with a new interacting dark energy model