منابع مشابه
Cardassian Expansion: Dark Energy Density from Modified Friedmann Equations
The Cardassian universe is a proposed modification to the Friedmann equation in which the universe is flat, matter dominated, and accelerating. In the ordinary Friedmann equation, the right hand side is a linear function of the energy density, H ∼ ρ. Here, instead, the right hand side of the Friedmann equation is a different function of the energy density, H ∼ g(ρ). This function returns to ord...
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We recently formulated a model of the universe based on an underlying W3symmetry. It allows the creation of the universe from nothing and the creation of baby universes and wormholes for spacetimes of dimension 2, 3, 4, 6 and 10. Here we show that the classical large time and large space limit of these universes is one of exponential fast expansion without the need of a cosmological constant. U...
متن کاملFuture Type Ia Supernova Data as Tests of Dark Energy from Modified Friedmann Equations
In the Cardassian model, dark energy density arises from modifications to the Friedmann equation, which becomes H = g(ρM), where g(ρM) is a new function of the energy density. The universe is flat, matter dominated, and accelerating. The distance redshift relation predictions of generalized Cardassian models can be very different from generic quintessence models, and can be differentiated with ...
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Recent measurements of type Ia supernovae as well as other concordant observations suggest that the expansion of our universe is accelerating. A dark energy component has usually been invoked as the most feasible mechanism for the acceleration. However, the effects arising from possible extra dimensions can mimic well the role of a dark energy through a modified Friedmann equation. In this work...
متن کاملOn asymptotic solutions of Friedmann equations
Our main aim is to apply the theory of regularly varying functions to the asymptotical analysis at infinity of solutions of Friedmann cosmological equations. A new constant C is introduced related to the Friedmann cosmological equations. Determining the values of C we obtain the asymptotical behavior of the solutions, i.e. of the expansion scale factor aðtÞ of a universe. The instance C < 4 is ...
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ژورنال
عنوان ژورنال: EPL (Europhysics Letters)
سال: 2020
ISSN: 1286-4854
DOI: 10.1209/0295-5075/129/50002