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Dark energy models with a single scalar field cannot cross the equation of state divide set by a cosmological constant. More general models that allow crossing require additional degrees of freedom to ensure gravitational stability. We show…

Astrophysics · Physics 2008-12-01 Wenjuan Fang , Wayne Hu , Antony Lewis

We study a two-phase modified Stefan problem modeling solid combustion and nonequilibrium phase transition. The problem is known to exhibit a variety of non-trivial dynamical scenarios. We develop a priori estimates and establish…

Analysis of PDEs · Mathematics 2007-05-23 M. L. Frankel , V. Roytburd

In this paper we consider Tachyonic scalar field as dark energy with interaction between components in the case of variable $G$ and $\Lambda$. We assume a flat Universe with specific form of scale factor and study cosmological parameters…

General Relativity and Quantum Cosmology · Physics 2015-02-03 J. Sadeghi , M. Khurshudyan , M. Hakobyan , H. Farahani

In this work we propose a new coupled generalized three-form dark energy model, in which dark energy are represented by a three-form field and other components are represented by ideal fluids. We first perform a dynamical analysis on the…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-19 Yanhong Yao , Xinhe Meng

We investigate the nonlinear parity-time (PT) symmetric coupler from a dynamical perspective. As opposed to linear PT-coupler where the PT threshold dictates the evolutionary characteristics of optical power in the two waveguides, in a…

Chaotic Dynamics · Physics 2016-12-09 Jyoti Prasad Deka , Amarendra K. Sarma

We apply the statefinder diagnostic to the torsion cosmology, in which an accounting for the accelerated universe is considered in term of a Riemann-Cartan geometry: dynamic scalar torsion. We find that there are some typical characteristic…

General Relativity and Quantum Cosmology · Physics 2011-03-31 Xin-zhou Li , Chang-bo Sun , Ping Xi

The proposal of pilgrim dark energy is based on the speculation that phantom-like dark energy possesses enough resistive force to preclude the black hole formation in the later universe. We explore this phenomenon by assuming the…

General Relativity and Quantum Cosmology · Physics 2015-06-22 M. Sharif , Abdul Jawad

Stability analysis of agegraphic dark energy in Brans-Dicke theory is presented in this paper. We constrain the model parameters with the observational data and thus the results become broadly consistent with those expected from experiment.…

General Physics · Physics 2015-06-03 H. Farajollahi , J. Sadeghi , M. Pourali , A. Salehi

In this work, we have considered the recently proposed new Tsallis Agegraphic Dark Energy model (NTADE) (Mod. Phys. Lett. A 34, 1950086, 2019) within the framework of a flat Friedmann-Robertson-Walker(FRW) Universe by taking various values…

General Relativity and Quantum Cosmology · Physics 2021-05-18 Umesh Kumar Sharma , Shikha Srivastava

We investigate the dynamical properties of dark energy through a detailed analysis of its equation of state parameter $w(z)$ as a function of redshift. We derive a general expression for $w(z)$ from the Friedmann-Lema\^itre-Robertson-Walker…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-29 J. W. Moffat , E. J. Thompson

We present here some recent results concerning scalar-tensor Dark Energy models. These models are very interesting in many respects: they allow for a consistent phantom phase, the growth of matter perturbations is modified. Using a…

Astrophysics · Physics 2016-11-15 R. Gannouji , D. Polarski , A. Ranquet , A. A. Starobinsky

We consider the possibility that the dark energy is made up of two or more independent components, each having a different equation of state. We fit the model with supernova and gamma-ray burst (GRB) data from resent observations, and use…

Astrophysics · Physics 2008-11-26 Yan Gong , Xuelei Chen

Scalar fields aptly describe equation of state of dark energy. The scalar field models were initially proposed to circumvent the fine tuning problem of cosmological constant. However, the model parameters also need a fine tuning of their…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-19 Archana Sangwan , Ashutosh Tripathi , H. K. Jassal

A class of dynamical dark energy models, dubbed Spinor Quintom, can be constructed by a spinor field $\psi$ with a nontraditional potential. We find that, if choosing suitable potential, this model is able to allow the equation-of-state to…

High Energy Physics - Theory · Physics 2008-11-26 Yi-Fu Cai , Jing Wang

In this work, we perform a comprehensive joint analysis of three representative dark energy models - ${\rm{\Lambda}CDM}$, the Chevallier-Polarski-Linder (CPL) parametrization, and the Generalised Emergent Dark Energy (GEDE) model - using…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-10 Tonghua Liu , Xiaolei Li , Jieci Wang

Geometrical diagnostic, involving the statefinder $\{r,s\}$ and $Om(x)$, is widely used to discriminate different dark energy models. We apply the statefinder $\{r,s\}$ and $Om(x)$ to purely kinetic k-essence dark energy model with…

General Relativity and Quantum Cosmology · Physics 2010-04-30 Xiang-Ting Gao , Rong-Jia Yang

In this paper, we study the structure of the global attractor for the multivalued semiflow generated by a nonlocal reaction-diffusion equation in which we cannot guarantee uniqueness of the Cauchy problem. First, we analyse the existence…

Dynamical Systems · Mathematics 2026-03-02 Rubén Caballero , Alexandre Nolasco Carvalho , Pedro Marín-Rubio , José Valero

The dynamics (in light-cone time) of the tachyon on an unstable brane in the background of a dilaton linear along a null coordinate is a non-local reaction-diffusion type equation, which admits a travelling front solution. We analyze the…

High Energy Physics - Theory · Physics 2014-07-24 Debashis Ghoshal , Preeda Patcharamaneepakorn

We study dynamical behaviors of the dark energy models interacting with dark matter and unparticle in the standard flat FRW cosmology. We considered four different interacting models and examined the stability of the critical points. We…

General Relativity and Quantum Cosmology · Physics 2010-04-15 Songbai Chen , Jiliang Jing

We examine the fixed points to first-order RG flow of a non-linear sigma model with background metric, dilaton and tachyon fields. We show that on compact target spaces, the existence of fixed points with non-zero tachyon is linked to the…

High Energy Physics - Theory · Physics 2009-11-11 J. Gegenberg , V. Suneeta