Related papers: Quintom evolution in power-law potentials
We derive the equation of state of tracker fields, which are typical examples of freezing quintessence (quintessence with the equation of state approaching toward -1), taking into account of the late-time departure from the tracker solution…
We study the late-time cosmological dynamics of a two-field dark energy model consisting of a canonical quintessence scalar field and a phantom scalar field in a spatially flat FLRW universe. The fields are minimally coupled to gravity and…
The red-shift space distortions in the galaxy power spectrum can be used to measure the growth rate of matter density perturbations delta_m. For dynamical dark energy models in General Relativity we provide a convenient analytic formula of…
We study how observationally to distinguish between a cosmological constant (CC) and an evolving dark energy with equation of state $\omega(Z)$. We focus on the value of redshift Z* at which the cosmic late time acceleration begins and…
We examine the behavior of dark energy models in the plane defined by w (the equation of state parameter for the dark energy) and w' (the derivative of w with respect to the logarithm of the scale factor). For non-phantom barotropic fluids…
The currently accelerated expansion of our Universe is unarguably one of the most intriguing problems in today's physics research. Two realistic non-minimal torsion-matter coupling $f(T)$ models have been established and studied in our…
Recent data from DESI Year 2 BAO, Planck CMB, and various supernova compilations suggest a preference for evolving dark energy, with hints that the equation of state may cross the phantom divide line ($w = -1$). While this behavior is seen…
We study constraints from the latest CMB, large scale structure (2dF, Abell/ACO, PSCz) and SN1a data on dark energy models with a sharp transition in their equation of state, w(z). Such a transition is motivated by models like vacuum…
In this work we study the cosmological evolution of a dark energy model with two scalar fields, i.e. the tachyon and the phantom tachyon. This model enables the equation of state $w$ to change from $w>-1$ to $w<-1$ in the evolution of the…
In this article we use the latest cosmological observations, including SNe, BAO, CC and RSD, to reconstruct the cosmological evolution via the Gaussian process. At the background level, we find consistency with the quintom dynamics for…
We apply a new non-parametric Bayesian method for reconstructing the evolution history of the equation-of-state $w$ of dark energy, based on applying a correlated prior for $w(z)$, to a collection of cosmological data. We combine the latest…
I review the observational prospects to constrain the equation of state parameter of dark energy and I discuss the potential of future imaging and redshift surveys. Bayesian model selection is used to address the question of the level of…
The recently released data of DESI DR2 favors a dynamical dark energy theory, with the equation of state crossing the cosmological constant boundary $w=-1$. In this paper, we briefly review quintom cosmology, especially the quintom bounce.…
We examine phantom dark energy models produced by a field with a negative kinetic term and a potential that satisfies the slow roll conditions: [(1/V)(dV/dphi)]^2 << 1 and (1/V)(d^2 V/dphi^2) << 1. Such models provide a natural mechanism to…
The time evolution of the equation of state $w$ for quintessence models with a scalar field as dark energy is studied up to the third derivative ($d^3w/da^3$) with respect to the scale factor $a$, in order to predict the future observations…
The dark energy transition between quintessence ($w>-1$) and phantom ($w<-1$) regimes (the crossing of the cosmological constant boundary) is studied using the dark energy equation of state. Models characterized by this type of transition…
In this talk I will firstly review on the current constraints on the equation of state of the dark energy from observational data, then present a new scenario of dark energy dubbed {\it Quintom}. The recent fits to the type Ia supernova…
We give a full investigation on the dynamics of power-law kinetic quintessence $L(X, \phi)=V(\phi)(-X+X^2)$ by considering the potential related parameter $\Gamma$($=\frac{V V''}{V'^2}$) as a function of another potential parameter…
We study the generation of a kination-dominated phase in the context of a quintessential model with an inverse-power-law potential and a Hubble-induced mass term for the quintessence field. The presence of kination is associated with an…
Recently, we give the robust $\sim2\,\sigma$ evidences of dynamical dark matter and beyond $2\,\sigma$ signals of the coexistence of dynamical dark matter and dynamical dark energy using current cosmological observations [1]. Here we…