相关论文: New Ekpyrotic Cosmology

The standard structure formation scenario is successful on linear scales. Several apparent problems affect it however at galactic scales, such as the small scale problems at low redshift and more recent issues involving early massive galaxy…

Using non-linear equation of state for pressure and density energy, we show that the universe is began with a smooth and isotropic bounce. We use a non-linear equation of state which is a binary mixture of perfect fluid and dark energy. We…

We calculate the power spectrum of cosmological perturbations originated from quantum vacuum fluctuations in bouncing scenarios proposed in Ref.~\cite{chamseddine2014cosmology} in the framework of mimetic cosmology. We show that all…

We discuss a cosmological model where the universe shrinks rather than expands during the radiation and matter dominated periods. Instead, the Planck mass and all particle masses grow exponentially, with the size of atoms shrinking…

A bouncing universe with a long period of contraction during which the average density is pressureless (the same equation of state as matter) as cosmologically observable scales exit the Hubble horizon has been proposed as an explanation…

It is widely believed that quantum field fluctuation in an inflating background creates the primeval seed perturbation which through subsequent evolution leads to the observed large scale structure of the universe. The standard inflationary…

In cyclic universe models based on a single scalar field (e.g., the radion determining the distance between branes in M-theory), virtually the entire universe makes it through the ekpyrotic smoothing and flattening phase, bounces, and…

Nonlinear electrodynamics, which acts as a source of gravity Einstein field equations, leads to emergent cosmology, an alternative solution which can avoid Big Bang singularity. In this paper, we explore the emerging universe in models of…

This paper investigates the manner in which classical universes are obtained in the no-boundary quantum state. In this context, universes can be characterised as classical (in a WKB sense) when the wavefunction is highly oscillatory, i.e.…

In this paper we take matter source with non-linear Equation of state (EoS) that has produced non-singular Emergent cosmology for spatially flat universe in General Relativity and minimally coupled scalar field with two different potentials…

In this paper, we model the bounce phase, stability, and the reconstruction of the universe by non-minimal kinetic coupling. In the process, we obtained importance information about the energy density and the matter pressure of the universe…

Horava-Lifshitz gravity, a recent proposal for a UV-complete renormalizable gravity theory, may lead to a bouncing cosmology. In this note we argue that Horava-Lifshitz cosmology may yield a concrete realization of the matter bounce…

We present a new approach to early universe cosmology. Inflation is replaced by a phase transition in which both matter and geometry are created simultaneously. We calculate the spectrum of metric perturbations and show that it is flat. We…

In this work we propose an alternative scheme for an Emergent Universe scenario where the universe is initially in a static state supported by a scalar field located in a false vacuum. The universe begins to evolve when, by quantum…

We propose a picture, within the pre-big-bang approach, in which the universe emerges from a bath of plane gravitational and dilatonic waves. The waves interact gravitationally breaking the exact plane symmetry and lead generically to…

Modeling of matter bounce in $f(R,T)$ gravity has been presented with no violation of the null energy condition. Only a closed universe with negative pressure is allowed in good agreement with some recent observations which favor a universe…

We explore the isotropization of a model anisotropic universe in the bouncing models using the ekpyrotic potential without assuming initial conditions corresponding to an ekpyrotic phase. In particular, we explore the way the use of…

A scale invariant spectrum of isocurvature perturbations is generated during collapse in the scaling solution in models where two or more fields have steep negative exponential potentials. The scale invariance of the spectrum is realised by…

We wish to demonstrate how the presence of a dynamic cosmological parameter, plus a model of the universe as a quantum computer can be combined to give us a picture of early universe inflationary physics which is quite non linear, with a…

The results from Planck2015, when combined with earlier observations from WMAP, ACT, SPT and other experiments, were the first observations to disfavor the "classic" inflationary paradigm. To satisfy the observational constraints,…