相关论文: Dynamical Emergence of FRW Cosmological Models
This paper explores models of the FLRW universe that incorporate a time-varying cosmological term $\Lambda(t)$. Specifically, we assume a power-law form for the cosmological term as a function of the scale factor: $\Lambda(t)=\Lambda_{0}…
Context. Explaining the accelerated expansion of the Universe is one of the fundamental challenges in physics today. Cosmography provides information about the evolution of the universe derived from measured distances, assuming only that…
Cosmology has entered an era of unprecedented precision, yet increasing accuracy has revealed cracks in the standard $\Lambda$CDM paradigm. Although the model remains highly successful when confronted with individual datasets, joint…
Cosmological stasis is a new type of epoch in the cosmological timeline during which the cosmological abundances of different energy components -- such as vacuum energy, matter, and radiation -- remain constant despite the expansion of the…
Present-day extragalactic observations are mostly rather well-modelled by a general-relativistic model, the $\Lambda$ CDM model. The model appears to surpass the limits of known physics by requiring that the Universe be dominated by "dark…
We address the question of the uniqueness of spatially flat $\Lambda$CDM-like evolution for FLRW cosmologies in General Relativity, i.e. whether any model other than the spatially flat $\Lambda$CDM can give rise to the same type of scale…
In this paper, we investigate the evolution of the early universe within an emergent fractional cosmological framework. The underlying formulation is conceptually rooted in generalized measure constructions, closely related to fractal…
The Fractal Bubble model has been proposed as a viable cosmology that does not require dark energy to account for cosmic acceleration, but rather attributes its observational signature to the formation of structure. In this paper it is…
A recently proposed Asymptotically Safe cosmology provides an elegant mechanism towards understanding the nature of dark energy and its associated cosmic coincidence problem. The underlying idea is that the accelerated expansion of the…
A thermodynamic description of cosmological spacetimes may provide insights into the fundamentals of the cosmic evolution that remain otherwise obscure, similar to `black hole thermodynamics'. We investigate the thermodynamic properties of…
With the recent progresses on the Type II supernovae, we attempt to investigate whether there does exist new physics beyond the standard cosmological paradigm, i.e., the cosmological constant $\Lambda$ plus cold dark matter ($\Lambda$CDM).…
We propose an alternative, nonsingular, cosmic scenario based on gravitationally induced particle production. The model is an attempt to evade the coincidence and cosmological constant problems of the standard model ($\Lambda$CDM) and also…
The discovery of scale acceleration evidenced from supernovae luminosities and spatial flatness of feature evolution in the cosmic microwave background presents a challenge to the understanding of the evolution of cosmological vacuum…
A five-dimensional cosmological model including a single perfect fluid is studied in the framework of dynamical system analysis. All the critical points of the system with their stability properties are listed and some representative phase…
The present paper deals with the dynamics of spatially flat Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmological model with a time varying cosmological constant $\Lambda$ where $\Lambda$ evolves with the cosmic time (t) through the…
The Nobel Prize winning confirmation in 1998 of the accelerated expansion of our Universe put into sharp focus the need of a consistent theoretical model to explain the origin of this acceleration. As a result over the past two decades…
Inspired by the well-studied $\Lambda_{\rm s}$CDM model, we propose and investigate a class of dynamical dark energy models that evolve from a negative cosmological constant, transitioning to a positive value at low redshifts. Specifically,…
In the context of the new standard LambdaCDM cosmology we resolve conflicts in the literature regarding fundamental aspects of the expansion of the universe and cosmic horizons and we link these concepts to observational tests. We derive…
While the LCDM framework has been incredibly successful for modern cosmology, it requires the admission of two mysterious substances as a part of the paradigm, dark energy and dark matter. Although this framework adequately explains most of…
Cosmography can be considered as a sort of a model-independent approach to tackle the dark energy/modified gravity problem. In this review, the success and the shortcomings of the $\Lambda$CDM model, based on General Relativity and standard…