相关论文: Current Issues for Inflation
Whichever could be the real theory of gravitation, the corresponding low-energy effective lagrangian will probably contain higher derivative terms. In this work we study the general conditions on those terms in order to produce enough…
The success of primordial nucleosynthesis imposes stringent bounds on the abundance of gravitational relics. This is particularly true for gravitinos, which - for models with gravitationally mediated supersymmetry breaking - are expected to…
Gravitinos are expected to be produced in any local supersymmetric model. Using their abundance prediction as a function of the reheating energy scale, it is argued that the next generation of Cosmic Microwave Background experiments could…
Does inflation provide a compelling explanation for why the universe is so large, so flat, and so old, and a predictive theory of density perturbations? In this brief contribution (based on the role of the author as moderator of the…
The changes of main paradigms on the structure and evolution of the Universe are reviewed. Two puzzles of the modern cosmology, the mean density of matter and the regularity of the Universe on large scales, as well as the possibility to…
Extended inflation is a promising new approach to implementing the inflationary universe scenario. This paper reviews recent advances including a new, more robust mechanism for ending extended inflation, a new prediction for the density…
We revisit the nonthermal gravitino production at the (p)reheating stage after inflation. Particular attention is paid to large field inflation models with a $\mathbb{Z}_2$ symmetry, for which the previous perturbative analysis is…
Although the dRGT massive gravity successfully explains the late-time cosmic acceleration, it cannot justify inflation. On the other hand, and in the frameworks of General Relativity and modified gravity, the interests and attempts to…
Cosmological issues of the gravitino production by the decay of a heavy scalar field $X$ are examined, assuming that the damped coherent oscillation of the scalar once dominates the energy of the universe. The coupling of the scalar field…
The early stages of the universe evolution are discussed according to the hot big bang model and the grand unified theories. The shortcomings of big bang are summarized and their resolution by inflationary cosmology is sketched.…
I review the present status of the problem of initial conditions for inflation and describe several ways to solve this problem for many popular inflationary models, including the recent generation of the models with plateau potentials…
We discuss the gravitational creation of superheavy particles $\chi$ in an inflationary scenario with a quartic potential and a non-minimal coupling between the inflaton $\varphi$ and the Ricci curvature: $\xi \varphi^2 R/2$. We show that…
We study the production of gravitinos during the preheating era after inflation by means of the non-perturbative Bogolyubov technique. Considering only the helicity $\pm 3/2$ states, the problem is reduced to the simpler Dirac fermions…
We discuss a realization of a small field inflation based on string inspired supergravities. In theories accompanying extra dimensions, compactification of them with small radii is required for realistic situations. Since the extra…
The formation of structure in the Universe offers some of the most powerful evidence in favour of the existence of dark matter in the Universe. We summarize recent work by ourselves and our collaborators, using linear and quasi-linear…
Inflation is studied in the context of asymptotically safe theories of gravitation. Conditions are explored under which it is possible to have a long period of nearly exponential expansion that eventually comes to an end.
We discuss a scenario that gravitinos produced non-thermally by an inflaton decay constitute dark matter in the present universe. We find that this scenario is realized for wide ranges of the inflaton mass and the vacuum expectation value.…
The radial direction of the Peccei--Quinn field can drive cosmic inflation, given a non-minimal coupling to gravity. This scenario has been considered to simultaneously explain inflation, the strong $CP$ problem, and dark matter. We argue…
We review work on the formation of gravitino condensates via the super-Higgs effect in the early Universe. This is a scenario for both inflating the early universe and breaking local supersymmetry (supergravity), entirely independent of any…
The super-inflationary phase is predicted by the Loop Quantum Cosmology. In this paper we study the creation of gravitational waves during this phase. We consider the inverse volume corrections to the equation for the tensor modes and…