相关论文: Multifluid Models for Cyclic Cosmology

We discuss cosmological models in six-dimensional spacetime. For codimension-1 branes, we consider a (4+1) braneworld model and discuss its cosmological evolution. For codimension-2 branes, we consider an infinitely thin conical braneword…

We discuss an alternative approach to quintessence modifying the usual equation of state of the cosmological fluid in order to see if going further than the approximation of perfect fluid allows to better reproduce the available data. We…

Although the current galaxy models yield calculations consistent with much of the data, many irregularities exist, exceptions have been found to the current models, the $\Lambda$CDM model apparently fails on galaxy scales, dark matter…

The main foundations of the standard $\Lambda $CDM model of cosmology are that: 1) The redshifts of the galaxies are due to the expansion of the Universe plus peculiar motions; 2) The cosmic microwave background radiation and its…

Our first goal in this work is to study general and model-independent properties of cyclic cosmologies. The large number of studies of bouncing cosmologies and different cyclic scenarios published recently calls for a proper understanding…

The universe content is considered as a non-perfect fluid with bulk viscosity and can be described by a general equation of state (endowed some deviation from the conventionally assumed cosmic perfect fluid model). An explicitly bulk…

We propose a unified framework that reconciles the stunning success of MOND on galactic scales with the triumph of the LambdaCDM model on cosmological scales. This is achieved through the physics of superfluidity. Dark matter consists of…

In this paper we are interested to consider mathematical ways to obtain different phenomenological fluids from two-component Tachyonic scalar fields. We consider interaction between components and investigate problem numerically.…

In this article, we examine a model which proposes a common explanation for the presence of additional attractive gravitational effects -- generally considered to be due to dark matter -- in galaxies and in clusters, and for the presence of…

Specific dark energy models with linear inhomogeneous time-dependent equation of state, within the framework of 4d Friedman-Robertson-Walker (FRW) cosmology, are investigated. It is demonstrated that the choice of such 4d inhomogeneous…

Multi-fluid models have recently been proposed as an approach to improving the representation of convection in weather and climate models. This is an attractive framework as it is fundamentally dynamical, removing some of the assumptions of…

We study the cosmological dynamics of non-minimally coupled matter models using the Brown's variational approach to relativistic fluids in General Relativity. After decomposing the Ricci scalar into a bulk and a boundary term, we construct…

The tired-light cosmology is considered in the framework of Kaluza-Klein theory in 5D. The solution of the five-dimensional semi-classical Einstein equations with nonzero five-dimensional energy-momentum tensor gives density of matter in…

The Standard Cosmological Model assumes that the Universe is, on average, homogeneous and isotropic for large scales (z>1), but this principle has been questioned from the results about Cosmic Microwave Background. This radiation has…

The two-fluid theory for superfluid hydrodynamics is derived from the fountain pressure result that condensed bosons move at constant entropy and are driven by the chemical potential gradient. Explicit results for $^4$He show that the…

We propose Multiscale Flow, a generative Normalizing Flow that creates samples and models the field-level likelihood of two-dimensional cosmological data such as weak lensing. Multiscale Flow uses hierarchical decomposition of cosmological…

It has recently been proposed, by assuming that dark matter is a superfluid, that MOND-like effects can be achieved on small scales whilst preserving the success of $\Lambda$CDM on large scales. Here we aim to provide the first set of…

D-dimensional cosmological model describing the evolution of a perfect fluid with negative pressure (x-fluid) and a fluid possessing both shear and bulk viscosity in n Ricci-flat spaces is investigated. The second equations of state are…

We present a brief review of brane-world models - models in which our observable Universe with its standard matter fields is assumed as localized on a domain wall (three-brane) in a higher dimensional surrounding (bulk) spacetime. Models of…

5D warped extra dimension models with multiple 3-branes can naturally realize multiple hierarchical mass scales which are ubiquitous in physics beyond the Standard Model. We discuss cosmological consequences of such multi-brane models with…