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

Abstract

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.

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

“…In such ΛCDM scenario, we have recently studied singularity-free and large-scale anomaly issues, the spectral index and tensor-to-scalar ratio relation in the inflation epoch [21], and calculated reheating energy and entropy [22]. The results are consistent with observations.…”

“…Second, the spontaneous gravitational creation of massive particle and anti-particle pairs in the Friedman Universe has been intensively studied, see examples [26-28, 30, 34]. The massive pairs' production [26] and oscillation [21,22] establish a condensate ground state |N pair ⟩ of the large number (N pair ≫ 1) and massive (M ≫ H) pairs of particles and antiparticles. They attribute to the microscopic fast-component H fast in the Hubble function H = H fast + H slow .…”

“…In addition, these beyond ΛCDM scenarios have not yet given an overall consistent description of inflation, reheating, and standard cosmology epochs. In the recently proposed ΛCDM model of time-varying Λ due to dark energy and matter interactions, we describe inflation epoch [21] and reheating epoch [22]. Following these studies, in this article, we try to find and explain a self-consistent dynamical solution for the cosmic fine-tuning and coincidence problems in the standard cosmology epoch.…”

Dark energy and matter interacting scenario to relieve H 0 and S 8 tensions*

“…The numerical solutions are too complex to proceed with data analysis. Nevertheless, the model accommodates scaling solutions, consistent with the principles of asymptotic safety in gravitational theories [59,61]. That is, the CDM quantities receive scaling factor (with ) corrections to counterparts when the redshift z becomes small (late times).…”

“…Using the concepts of asymptotic safety [59] and particle production [60] in gravitational field theory, Ref. [61] introduced a CDM model characterized by a dynamical vacuum energy component that interacts with matter and radiation. The density of vacuum energy, , undergoes conversion to matter (radiation) and vice versa.…”