Related papers: Energy Conditions and Supernovae Observations
Non-gravitational interaction between two barotropic dark fluids, namely the pressureless dust and the dark energy in a spatially flat Friedmann-Lema\^{i}tre-Robertson-Walker model has been discussed. It is shown that for the interactions…
We study the likelihood of energy condition violations in the history of the Universe. Our method is based on a set of functions that characterize energy condition violation. FLRW cosmological models are built around these "indication…
Recent discoveries, e.g., by JWST and DESI, have elevated the level of tension with inflationary $\Lambda$CDM. For example, the empirical evidence now suggests that the standard model violates at least one of the energy conditions from…
The Standard Model of elementary particle physics is one of the most successful models of contemporary physics, its predictions being in full agreement with experiments. In this manuscript we consider the Lagrangian of the Standard Model as…
The energy conditions of general relativity permit one to deduce very powerful and general theorems about the behaviour of strong gravitational fields and cosmological geometries. However, the energy conditions these theorems are based on…
In Phys. Rev. D 102, 024057 (2020), the authors studied energy conditions in $f(Q)$ theory following the same path as researchers handled the energy conditions in the curvature-based modified gravity theories, like $f(R)$ or $f(R,G)$…
The present paper examines the validity of energy bounds in a modified theory of gravity involving non-minimal coupling of torsion scalar and perfect fluid matter. In this respect, we formulate the general inequalities of energy conditions…
New observational constraints on the cosmic matter density $\Omega_m$ and an effectively redshift-independent equation of state parameter $w_x$ of the dark energy are obtained while simultaneously testing the strong and null energy…
Recently, some Lema{\^{\i}}tre-Tolman-Bondi metrics have been considered as models alternative to the dark energy within the Friedmann-Lema{\^{\i}}tre-Robertson-Walker universes. The vanishing of the intrinsic energy of these metrics is…
This note summarizes a model-independent analysis of the age of the universe problem that trades off precision in favour of robustness: The energy conditions of Einstein gravity are designed to extract as much information as possible from…
Among the various possibilities to probe the theory behind the recent accelerated expansion of the universe, the energy conditions (ECs) are of particular interest, since it is possible to confront and constrain the many models, including…
The dynamics of bouncing universes is characterized by violating certain coordinate invariant restrictions on the total energy-momentum tensor, customarily referred to as energy conditions. Although there could be epochs where the null…
We describe energy--momentum conservation in relativistic perturbation theory in general FRW backgrounds with causal source terms, such as the presence of cosmic defect networks. We provide a prescription for a linear energy--momentum…
The attempt to describe the recent accelerated expansion of the Universe includes different propositions for dark energy models and modified gravity theories. Establish their features in order to discriminate and even rule out part of these…
We present and discuss the bounds from the energy conditions on a general f(R) functional form in the framework of metric variational approach. As a concrete application of the energy conditions to locally homogeneous and isotropic…
In this exclusive study of the modified $f(Q)$ theory of gravity in the open and closed type Friedmann-Lema\^itre-Robertson-Walker (FLRW) universe model, we impose some constraints from the classical energy conditions. The viable range of…
We examine the validity of classical energy conditions in nonsingular bouncing cosmological solutions arising in quadratic curvature gravity minimally coupled to a scalar field. Focusing on the null, weak, strong, and dominant energy…
A phenomenological approach is proposed to the problem of universe accelerated expansion and of the dark energy nature. A general class of models is introduced whose energy density depends on the redshift $z$ in such a way that a smooth…
Energy conditions can play an important role in defining the cosmological evolution. Specifically acceleration/deceleration of cosmic fluid, as well as the emergence of Big Rip singularities, can be related to the constraints imposed by the…
The recent observations of type Ia supernovae suggest that the universe is accelerating now and decelerated in the recent past. This may be the evidence of the breakdown of the standard Friedmann equation. The Friedmann equation $H^2\sim…