相关论文: Parametrising non-linear dark energy perturbations

The late stages of large-scale structure evolution are treated semi-analytically within the framework of modified halo model. We suggest simple yet accurate approximation for relating the non-linear amplitude to linear one for spherical…

We propose a new cosmological model that considers dark matter as a barotropic fluid with a constant equation of state parameter and interprets dark energy as the phenomenological emergent dark energy rather than a cosmological constant.…

We present a non-perturbative calculation of the form factors which contribute to the amplitudes for the radiative decays $P\to \ell \bar \nu_\ell \gamma$, where $P$ is a pseudoscalar meson and $\ell$ is a charged lepton. Together with the…

This paper is concerned with fully discrete finite element methods for approximating variational solutions of nonlinear stochastic elastic wave equations with multiplicative noise. A detailed analysis of the properties of the weak solution…

Upcoming and existing large-scale surveys of galaxies require accurate theoretical predictions of the dark matter clustering statistics for thousands of mock galaxy catalogs. We demonstrate that this goal can be achieve with our new…

We show how one can test the cosmological Poisson equation by requiring only the validity of three main assumptions: the energy-momentum conservation equations of matter, the equivalence principle, and the cosmological principle. We first…

A novel approach to the class of cosmic barotropic fluids in which the speed of sound squared is defined as a function of the Equation of State parameter, so called $c_s^2(w)$ models, is examined. For this class of models, a new analytical…

The primary science driver for 3D galaxy surveys is their potential to constrain cosmological parameters. Forecasts of these surveys' effectiveness typically assume Gaussian statistics for the underlying matter density, despite the fact…

The cause of the accelerated expansion of the Universe poses one of the most fundamental questions in physics today. In the absence of a compelling theory to explain the observations, a first task is to develop a robust phenomenology. If…

We study the imprints of an effective dark energy fluid in the large scale structure of the universe through the observed angular power spectrum of galaxies in the relativistic regime. We adopt the phenomenological approach that introduces…

We propose a Friedmann-Lemaitre-Robertson-Walker cosmological model with a scalar field that represents dark energy. A new parametrization of the deceleration parameter is introduced of the form $q = 1 + \eta (1 + \mu a^{\eta})$ where…

We consider nonlinear redshift-dependent equation of state parameters as dark energy models in a spatially flat Friedmann-Lema\^itre-Robertson-Walker universe. To depict the expansion history of the universe in such cosmological scenarios,…

Relativistic effects are sensitive to subtle changes in dark energy. These effects grow on very large scales and at high redshifts, which will be the reach of upcoming surveys. We investigate these effects in both the linear and the angular…

We analyze time-dependent dark energy equations of state through linear and nonlinear structure formation and their quintessence potentials, characterized by fast, recent transitions, inspired by parameter space studies of selected classes…

Theoretical differences in the growth of structure offer the possibility that we might distinguish between modified gravity theories of dark energy and \LambdaCDM. A significant impediment to applying current and prospective large scale…

We propose a new approximated expression for non-linear Dark Matter power spectrum much beyond BAO scales. The proposed expression agrees with the result of N-body simulation with the accuracy better than 2 % up to k=1.0 [h/Mpc] and k=0.7…

We discuss a nonlocal modification of gravity obtained adding a term $m^2 R\,\Box^{-2}R$ to the Einstein-Hilbert action. We find that the mass parameter $m$ only affects the non-radiative sector of the theory, while the graviton remains…

In this paper we will demonstrate possible existence of more exotic forms of interaction taking into account, that dark energy can be parametrized as a varying polytropic uid suggested recently by the first author. On going research in both…

In this work we extend our earlier phenomenological model for a gravitational phase transition (GPT) and its generalization to early times by letting the modifications in the linearly-perturbed Einstein equations be scale-dependent. These…

The cosmological model consisting of a nonlinear magnetic field obeying the Lagrangian L= \gamma F^{\alpha}, F being the electromagnetic invariant, coupled to a Robertson-Walker geometry is tested with observational data of Type Ia…