We analyze the early stage of evolution of a universe with two scale factors proposed in [1] when matter is present. The scale factors describe two causally disconnected patches of the universe interacting trough a non-trivial Poisson bracket structure in the momentum sector characterized by one parameter κ. We studied two scenarios in which one of the patches is always filled with relativistic matter while the other contains relativistic matter in one case, and non-relativistic matter in the second case. By solving numerically the set of equations governing the dynamics, we found that the energy content of one sector drains to the other and from here it is possible to constraint the deformation parameter κby imposing that the decay of the energy density happens, at most, at the Big Bang Nucleosynthesis temperature in order to return to the usual behavior of radiation. The relation with Non Standard Cosmologies is also addressed.
We discuss a scenario that the dark matter in late time universe emerges as part of the holographic stress-energy tensor on the hypersurface in higher dimensional flat spacetime. Firstly we construct a toy model with a de Sitter hypersurface as the holographic screen in the flat bulk. After adding the baryonic matter on the screen, we assume that both of the dark matter and dark energy can be described by the Brown-York stress-energy tensor. From the Hamiltonian constraint equation in the flat bulk, we find an interesting relation between the dark matter and baryonic matter's energy density pa…
In this paper, we introduce a new type of matter that has origin in $p$-adic strings, i.e., strings with a $p$-adic worldsheet. We investigate some properties of this $p$-adic matter, in particular its cosmological aspects. We start with crossing symmetric scattering amplitudes for $p$-adic open strings and related effective nonlocal and nonlinear Lagrangian which describes tachyon dynamics at the tree level. Then, we make a slight modification of this Lagrangian and obtain a new Lagrangian for non-tachyonic scalar field. {Using this new Lagrangian in the weak field approximation as a matter i…
Starting from the generalized Raychaudhuri equation with torsion and non-metricity, and considering an FLRW spacetime we derive the most general form of acceleration equation in the presence of torsion and non-metricity. That is we derive the cosmic acceleration equation when the nonRiemannian degrees of freedom are also taken into account. We then discuss some conditions under which torsion and non-metricity accelerate/decelerate the expansion rate of the Universe.
In this paper we analyze the Dark Matter problem and the distribution of matter through two different approaches, which are linked by the possibility that the solution of these astronomical puzzles should be sought in the quantum imprinting of the Universe. The first approach is based on a cosmological model formulated and developed in the last ten years by the first and third authors of this paper; the so-called Archaic Universe. The second approach was formulated by Rosen in 1933 by considering the Friedmann-Einstein equations as a simple one-dimensional dynamical system reducing the cosmolo…
Inflaton and metric fluctuations in the early universe from a 5D vacuum state
在这封信中，我们完成了以前介绍的形式主义，研究规范不变的度量涨落从一个非紧卡鲁扎-克莱因引力理论，研究早期宇宙的演化。度规场和暴胀子场涨落的演化是相互关联的。得到了<δρ/ρ_b $ depends on the coupling of $ Φ $ with $ δ $ and the spectral index of its spectrum is: $ 0.9483 < n_1 < 1$.
The observational evidence points to the origin of our Universe from a big-bang explosion, the normal matter we observed can be well explained by the particles created in the strong and weak interacting phases of the early universe. The dark energy and dark matter, which occupy major contents of the universe, may be created from earlier times than that of quarks. We propose that the dark energy is an integration of the gravitational waves (GWs) in early universe, and the dark matter is composed of x particles which are created earlier and have much heavier mass than quarks in early universe. T…
