Related papers: Tachyonic dark energy- Constraints from current ob…
In the present work we study a dark energy model in which a non-linear scalar field (tachyon) with a Born-Infeld type of action is responsible for the observed cosmic acceleration. The potential of the tachyon is well-motivated since it…
Recent analyses from the DESI collaboration suggest that the dark energy density of the Universe may be decreasing with time, slowing the acceleration of the scale factor $a$. Typically these studies are performed assuming an ansatz for the…
Recent measurements of Baryon Acoustic Oscillations (BAO) and distance moduli from Type Ia supernovae suggest a preference for Dynamical Dark Energy (DDE) scenarios characterized by a time-varying equation of state (EoS). This focused…
In this study, we investigate the oscillatory dark energy model $w_{\sin}\mathrm{CDM}$ based on the DESI BAO data together with OHD, Pantheon Plus, and SH0ES measurements. We examine how the DESI data influence the dark energy…
We explore the dynamics of dark energy models based on a Dirac-Born-Infeld (DBI) tachyonic action, studying a range of potentials. We numerically investigate the existence of tracking behaviour and determine the present-day value of the…
The tachyon field in cosmology is studied by applying the generating function method to obtain exact solutions. The equation of state parameter of the tachyon field is $w=-1+\epsilon\dot{\phi^2}$, which can be expressed as a function in…
Rolling tachyon field models are among the candidates suggested as explanations for the recent acceleration of the Universe. In these models the field is expected to interact with gauge fields and lead to variations of the fine-structure…
One of the main aims in the next generation of precision cosmology experiments will be an accurate determination of the equation of state (EOS) for the dark energy (DE). If the latter is dynamical, the resulting barotropic index \omega…
The equation of state (EOS) of the dark energy is the key parameter to study the nature of the dark energy from the observation. Though the dark energy is found to be well consistent with the cosmological constant with a constant EOS of…
Baryon acoustic oscillation measurements by the Dark Energy Spectroscopic Instrument (Data Release 1) have revealed exciting results that show evidence for dynamical dark energy at $\sim3\sigma$ when combined with cosmic microwave…
We compute the Bayesian evidences for one- and two-parameter models of evolving dark energy, and compare them to the evidence for a cosmological constant, using current data from Type Ia supernova, baryon acoustic oscillations, and the…
We perform fits to DESI, CMB and supernova data to understand the physical origin of the DESI hint for dynamical dark energy. We find that the linear parametrization of the equation of state $w$ may guide to misleading interpretations, such…
In the symmetric teleparallel gravity framework, we study the cosmic dynamics of the universe with dark energy equation of state (EoS) parameter having non-linear forms. The non-metricity scalar induced by the dark energy EoS parameter…
The latest findings from the DESI (Dark Energy Spectroscopic Instrument) data release 1 (DR1) [1], combined with data from the cosmic microwave background and supernovae, suggest a preference for dynamical dark energy over the cosmological…
Since the late 1990's observations of type Ia Supernova, our universe is predicted to experience a late time cosmic acceleration. Theoretical support to this observation were intended to be built via proposition of a hypothetical fluid…
We investigate the cosmological implications of a generalized total equation of state (EoS) model by constraining its parameters using observational datasets to effectively characterize the universe's expansion history and its dynamic…
Recent results from DESI BAO measurements, together with Planck CMB and Pantheon+ data, suggest that there may be a `phantom' phase ($w_{\rm de}<-1$) in the expansion of the Universe. This inference follows when the $w_0, w_a$…
We conduct an extended analysis of dark energy constraints, in support of the findings of the DESI DR2 cosmology key paper, including DESI data, Planck CMB observations, and three different supernova compilations. Using a broad range of…
We present a complete analysis of the observational constraints and cosmological implications of our Bound Dark Energy (BDE) model aimed to explain the late-time cosmic acceleration of the universe. BDE is derived from particle physics and…
Recent observational results from the DESI collaboration reveal tensions with the standard $\Lambda$CDM model and favour a scenario in which dark energy (DE) decays over time. The DESI DR2 data also suggest that the DE equation of state…