9 research outputs found
Anisotropic cosmological models with spinor and scalar fields and viscous fluid in presence of a term: qualitative solutions
The study of a self-consistent system of interacting spinor and scalar fields
within the scope of a Bianchi type I (BI) gravitational field in presence of a
viscous fluid and term has been carried out. The system of equations
defining the evolution of the volume scale of BI universe, energy density and
corresponding Hubble constant has been derived. The system in question has been
thoroughly studied qualitatively. Corresponding solutions are graphically
illustrated. The system in question is also studied from the view point of blow
up. It has been shown that the blow up takes place only in presence of
viscosity.Comment: 18 pages, 14 figures, 12 Tables, section "Basic equations" has been
rewritte
Bianchi type I universe with viscous fluid: A qualitative analysis
The nature of cosmological solutions for a homogeneous, anisotropic Universe
given by a Bianchi type-I (BI) model in the presence of a Cosmological constant
is investigated by taking into account dissipative process due to
viscosity. The system in question is thoroughly studied both analytically and
numerically. It is shown the viscosity, as well as the term exhibit
essential influence on the character of the solutions. In particular a negative
gives rise to an ever-expanding Universe, whereas, a suitable choice
of initial conditions plus a positive can result in a
singularity-free oscillatory mode of expansion. For some special cases it is
possible to obtain oscillations in the exponential mode of expansion of the BI
model even with a negative , where oscillations arise by virtue of
viscosity.Comment: RevTex, 16 pages, 32 figure
Status and initial physics performance studies of the MPD experiment at NICA
The Nuclotron-based Ion Collider fAcility (NICA) is under construction at the Joint Institute for Nuclear Research (JINR), with commissioning of the facility expected in late 2022. The Multi-Purpose Detector (MPD) has been designed to operate at NICA and its components are currently in production. The detector is expected to be ready for data taking with the first beams from NICA. This document provides an overview of the landscape of the investigation of the QCD phase diagram in the region of maximum baryonic density, where NICA and MPD will be able to provide significant and unique input. It also provides a detailed description of the MPD set-up, including its various subsystems as well as its support and computing infrastructures. Selected performance studies for particular physics measurements at MPD are presented and discussed in the context of existing data and theoretical expectations