相关论文: Thermodynamics of the early Universe with mirror d…
We have investigated the thermodynamical properties of the Universe with dark energy. Adopting the usual assumption in deriving the constant co-moving entropy density that the physical volume and the temperature are independent, we observed…
The study of particle creation phenomena at the expense of the gravitational field is of great research interest. It might solve the cosmological puzzle single-handedly, without the need for either dark energy or the modified theory of…
We present a novel candidate for cold dark matter consisting of condensed Cooper pairs in a theory of interacting fermions with broken chiral symmetry. Establishing the thermal history from the early radiation era to the present, the…
The Universe's early thermal history is poorly constrained, and it is possible that it underwent a period of early matter domination driven by a heavy particle or an oscillating scalar field that decayed into radiation before the onset of…
The evolution of the Universe between inflation and the onset of big bang nucleosynthesis is difficult to probe and largely unconstrained. This ignorance profoundly limits our understanding of dark matter: we cannot calculate its thermal…
It is quite possible that the reheat temperature of the universe is extremely low close to the scale of Big Bang nucleosynthesis, i.e. $T_{R}\sim 1-10$ MeV. At such low reheat temperatures generating matter anti-matter asymmetry and…
The idea of the universe with a mirror sector having all particles and forces identical to those in the familiar sector has been proposed in the context of neutrino physics as well as superstring theories. Assuming that all the quark and…
This article gives a brief qualitative description of the possible evolution of the early Universe between the end of an inflationary epoch and the end of Big Bang nucleosynthesis. After a general introduction, establishing the minimum…
The thermal and expansion history of the Universe before big bang nucleosynthesis is unknown. We investigate the evolution of cosmological perturbations through the transition from an early matter era to radiation domination. We treat…
A common feature in the thermodynamic analysis of homogeneous and isotropic world models is the assumption that the temperature of the fluids inside the cosmic horizon (including dark energy) coincides with the temperature of the latter,…
We present a novel candidate for cold dark matter consisting of condensed Cooper pairs in a theory of interacting fermions with broken chiral symmetry. Establishing the thermal history from the early radiation era to the present, the…
Assuming that the matter filling the background geometry in the Early Universe was a free gas and no phase transitions took place, we discuss the thermodynamics of this closed system using classical approaches. We found that essential…
Mirror matter is a dark matter candidate. In this paper, we re-examine the linear regime of density perturbation growth in a universe containing mirror dark matter. Taking adiabatic scale-invariant perturbations as the input, we confirm…
Measurements of the primordial element abundances provide us with an important probe of our universe's early thermal history, allowing us to constrain the expansion rate and composition of our universe as early as $\sim 1 \, {\rm s}$ after…
The freeze-in mechanism has been shown to allow the simultaneous generation of cosmic dark matter and a viable matter-antimatter asymmetry in the universe. When the underlying interactions are described by higher-dimensional,…
We investigate a new bound on the low reheating temperature in a scenario where the Universe experiences early matter-domination before reheating after which the standard big bang cosmology begins. In many models of dark matter (DM), the…
We consider a cluster of Primordial Black Holes which is decoupled from the cosmological expansion (Hubble flow) and this region is heated as compared to the surrounding matter. The increased temperature inside the region can be explained…
We extend previous studies of big bang nucleosynthesis, with the assumption that ordinary matter and dark matter sectors are entangled through the number of degrees of freedom entering the Friedmann equations. This conjecture allows us to…
Thermal relics lighter than an MeV contribute to the energy density of the universe at the time of nucleosynthesis and recombination. Constraints on extra radiation degrees of freedom typically exclude even the simplest of such dark…
Primordial nucleosynthesis is considered a success story of the standard big bang (SBB) cosmology. The cosmological and elementary particle physics parameters are believed to be severely constrained by the requirement of correct abundances…