相关论文: Warm and Cold Dark Matter in Bouncing Universe

We discuss a cosmology in which cold dark matter begins to decay into relativistic particles at a recent epoch (z < 1). We show that the large entropy production and associated bulk viscosity from such decays leads to an accelerating…

We present an in-depth study of two-component cold dark matter via extensive N-body simulations. We examine various cosmological observables including the temperature evolution, power spectrum, density perturbation, maximum circular…

We find a class of solutions for a homogeneous and isotropic universe in which the initially expanding universe stops expanding, experiences contraction, and then expands again (the "bounce"), in the framework of Einstein gravity with a…

The thermodynamic behavior of vacuum decaying cosmologies is investigated within a manifestly covariant formulation. Such a process corresponds to a continuous irreversible energy flow from the vacuum component to the created matter…

We study the non-adiabatic cosmological production of ultra light dark matter (ULDM) under a minimal set of assumptions: a free ultra light real scalar as a spectator field in its Bunch-Davies vacuum state during inflation and instantaneous…

We consider a quantum junction described by a 1+1-dimensional boundary conformal field theory (BCFT). Our analysis focuses on correlations emerging at finite temperature, achieved through the computation of entanglement measures. Our…

We explore the possible phases of a condensed dark matter (DM) candidate taken to be in the form of a fermion with a Yukawa coupling to a scalar particle, at zero temperature but at finite density. This theory essentially depends on only…

(Abridged) Despite the success of Cold Dark Matter (CDM) in explaining a wide range of observations, the microscopic nature of dark matter is still unknown. Attempts to detect WIMPs, the most commonly studied form, have not yet succeeded.…

We propose a new thermal dark matter candidate whose abundance is determined by the freezeout of inverse decays. The relic abundance depends parametrically only on a decay width, while matching the observed value requires that the coupling…

In loop quantum cosmology (LQC), the initial singularity is replaced by a quantum bounce, leading to a universal post-bounce evolution characterized by three distinct epochs: bouncing, transition, and slow-roll inflation, before the hot…

It is shown that if there are two distinct phase transition temperatures to the hadronic phase ( as is currently favoured), then QCD demands a condensation to a weakly interacting massive glueball. This glueball then becomes a natural…

Gravitational dark matter (DM) is the simplest possible scenario that has recently gained interest in the early universe cosmology. In this scenario, DM is assumed to be produced from the decaying inflaton through the gravitational…

The big bang singularity could be understood as a breakdown of Einstein's General Relativity at very high energies. Adopting this viewpoint, other theories, that implement Einstein Cosmology at high energies, might solve the problem of the…

We present a mechanism for dark matter (DM) production involving a self-interacting sector that at early times is ultra-relativistic but far-underpopulated relative to thermal equilibrium (such initial conditions often arise, e.g., from…

The present paper is devoted to the study of bouncing cosmology in $f(R,T)$ modified gravity where we presume $f(R,T) = R + 2 \lambda T$, with $R$ the Ricci scalar, $T$ the trace of energy momentum tensor and $\lambda$ the model parameter.…

For the anisotropic Universe filled with massless vector field in the General Relativity frame we obtain bouncing solution for one of scale factors. We obtain the Universe with finite maximal energy density, finite value of…

Using an approximate solution to the $N$-body problem in general relativity, and the \emph{principle of local isotropy at any point}, we construct a cosmological model, with zero curvature, for a universe composed uniquely by collision-less…

Fuzzy (wave) dark matter (FDM), the dynamical model underlying an ultralight bosonic dark matter species, produces a rich set of non-gravitational signatures that distinguishes it markedly from the phenomenologically related warm (particle)…

Using Relativistic Quantum Geometry we study back-reaction effects of space-time inside the causal horizon of a static de Sitter metric, in order to make a quantum thermodynamical description of space-time. We found a finite number of…

We study the entropy of a FRW universe filled with dark energy (cosmological constant, quintessence or phantom). For general or time-dependent equation of state $p=w\rho$ the entropy is expressed in terms of energy, Casimir energy, and $w$.…