A5015730413- Cosmology and Gravitation Theories
- Galaxies: Formation, Evolution, Phenomena
- Black Holes and Theoretical Physics
- Dark Matter and Cosmic Phenomena
- Geophysics and Gravity Measurements
- Relativity and Gravitational Theory
- Solar and Space Plasma Dynamics
- Particle physics theoretical and experimental studies
- Pulsars and Gravitational Waves Research
- Advanced Thermodynamics and Statistical Mechanics
- Noncommutative and Quantum Gravity Theories
- Advanced Differential Geometry Research
- Gamma-ray bursts and supernovae
- Radio Astronomy Observations and Technology
- Astronomy and Astrophysical Research
- Earth Systems and Cosmic Evolution
- Computational Physics and Python Applications
- Stochastic processes and financial applications
- Astrophysics and Cosmic Phenomena
- Experimental and Theoretical Physics Studies
- Quantum Electrodynamics and Casimir Effect
- Statistical Mechanics and Entropy
- Superconducting and THz Device Technology
- Particle Accelerators and Free-Electron Lasers
- Neutrino Physics Research
Presidency University
2018-2025
Durban University of Technology
2022-2025
Liaoning Normal University
2024
Raiganj University
2017-2019
Indian Institute of Science Education and Research Kolkata
2016-2018
Jadavpur University
2013-2018
Abstract The simplest ΛCDM model provides a good fit to large span of cosmological data but harbors areas phenomenology and ignorance. With the improvement number accuracy observations, discrepancies among key parameters have emerged. most statistically significant tension is 4 σ 6 disagreement between predictions Hubble constant, H 0 , made by early time probes in concert with ‘vanilla’ model, late time, model-independent determinations from local measurements distances redshifts. high...
We investigate the observational consequences of a novel class stable interacting dark energy (IDE) models, featuring interactions between matter (DM) and (DE). In first part our work, we start by considering two IDE models which are known to present early-time linear perturbation instabilities. Applying transformation depending on equation state (EoS) DM-DE coupling, then obtain models. Subsequently, derive robust accurate constraints parameters these assuming constant EoS wx for DE fluid,...
We investigate interacting scenarios which belong to a wider class, since they include dynamical dark energy component whose equation of state follows various one-parameter parametrizations. confront them with the latest observational data from Cosmic Microwave Background (CMB), Joint light-curve (JLA) sample Supernovae Type Ia, Baryon Acoustic Oscillations (BAO), Hubble parameter measurements Chronometers (CC) and gaussian prior on $H_0$. In all examined we find non-zero interaction,...
In this paper, we consider the effects of adding curvature in extended cosmologies involving a free-to-vary neutrino sector and different parametrizations dark energy (DE). We make use Planck 2018 cosmic microwave background temperature polarization data, baryon acoustic oscillations Pantheon type Ia supernovae data. Our main result is that nonflat Universe cannot be discarded light current astronomical because find an indication for closed most DE explored work. On other hand, forcing to...
Abstract Recent Baryon Acoustic Oscillation (BAO) measurements released by DESI, when combined with Cosmic Microwave Background (CMB) data from Planck and two different samples of Type Ia supernovae (Pantheon-Plus DESY5) reveal a preference for Dynamical Dark Energy (DDE) characterized present-day quintessence-like equation state that crossed into the phantom regime in past. A core ansatz this result is assuming linear Chevallier-Polarski-Linder (CPL) parameterization w ( ) = 0 + (1- to...
The main aim of this work is to use a model-independent approach, along with late-time observational probes, reconstruct the dark energy (DE) equation state <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msub><a:mrow><a:mi>w</a:mi></a:mrow><a:mrow><a:mi>DE</a:mi></a:mrow></a:msub><a:mo stretchy="false">(</a:mo><a:mi>z</a:mi><a:mo stretchy="false">)</a:mo></a:mrow></a:math>. Our analysis showed that, for late time universe, <e:math...
Almost in all interacting dark energy models present the literature, stability of model becomes potentially sensitive to equation state parameter $w_x$, and a singularity arises at `$w_x = -1$'. Thus, it mandatory test into two separate regions, namely, for quintessence phantom. This essentially brings discontinuity parameters space $w_x$. Such can be removed with some specific choices interaction or coupling function. In work we choose one particular between matter which successfully remove...
We use the latest compilation of observational Hubble parameter measurements estimated with differential evolution cosmic chronometers, in combination local value constant recently measured 2.4% precision, to constrain cosmological scenario where dark energy interacts directly matter sector. To diminish degeneracy between parameters we additionally consider standard probes, such as supernovae type Ia from joint light-curve analysis samples, baryon acoustic oscillation distance (BAO), and...
We use the local value of Hubble constant recently measured with 2.4% precision, as well latest compilation cosmic chronometers data, together standard probes such Supernovae Type Ia and Baryon Acoustic Oscillation distance measurements, in order to impose constraints on viable most used f(T) gravity models, where T is torsion scalar teleparallel gravity. In particular, we consider three models two parameters, out which one independent, quantify their deviation from $\Lambda$CDM cosmology...
The phenomenological parametrizations of dark-energy (DE) equations state can be very helpful, since they allow for the investigation its cosmological behavior despite fact that underlying theory is unknown. However, although there has been a large amount research on DE which involve two or more free parameters, one-parameter seem to underestimated. We perform detailed observational confrontation five models, with data from cosmic microwave background (CMB), Joint light-curve analysis sample...
We study large-scale inhomogeneous perturbations and instabilities of interacting dark energy (IDE) models. Past analysis perturbative instabilities, has shown that we can only test IDE models with observational data when its parameter ranges are either $w_{x}\geq -1$ $\xi \geq 0,$ or $w_{x}\leq -1~$ $~\xi \leq 0$, where $w_{x}$ is the equation state (EoS), $\xi$ a coupling governing strength direction transfer. show by adding factor $(1+w_{x})$ to background transfer, whole space be tested...
We investigate various scenarios which include interaction forms between dark matter and energy that exhibit sign reverse, namely where the transfer of fluids changes during evolution. study large-scale inhomogeneities in such interacting we confront them with latest astronomical data. Our analysis shows sign-changeable models are able to produce stable perturbations. Additionally, data seem slightly favor a non-zero interaction, however, within $1\ensuremath{\sigma}$ confidence level (CL)...
We consider two stable Interacting Dark Matter-Dark Energy models and confront them against current Cosmic Microwave Background data from the Planck satellite. then generate luminosity distance measurements (103) mock Gravitational Wave events matching expected sensitivity of proposed Einstein Telescope. use these to forecast how addition standard sirens can improve limits on coupling strength (ξ). find that Waves reduce uncertainty by a factor 5. Moreover, if underlying cosmological model...
Non-gravitational interaction between two barotropic dark fluids, namely the pressureless dust and energy in a spatially flat Friedmann-Lemaître–Robertson–Walker model, has been discussed. It is shown that for interactions are linear terms densities of components their first order derivatives, net density governed by second-order differential equation with constant coefficients. Taking generalized interaction, which includes number already known as special cases, dynamics universe described...
The paper deals with a theoretical model for interacting dark energy. interaction between the cold matter (dust) and energy has been assumed to be non-gravitational in nature. Exact analytic cosmological solutions are obtained both constant variable equation of state It is found that, very small value coupling parameter (in term), asymptotically extends up $\Lambda$CDM, while can enter into phantom domain asymptotically, if not so small. Both then analyzed 194 Supernovae Type Ia data. best...
In the background of a homogeneous and isotropic space-time with zero spatial curvature, we consider interacting scenarios between two barotropic fluids, one is pressureless dark matter other energy (DE), in which equation state (EoS) DE either constant or time-dependent. particular, for EoS DE, show that evolution equations both fluids can be analytically solved. For all these scenarios, model parameters have been constrained using current astronomical observations from Type Ia supernovae,...
Stability analysis of interacting dark-energy models generally divides its parameters space into two regions, (i) ${w}_{x}\ensuremath{\ge}\ensuremath{-}1$ and $\ensuremath{\xi}\ensuremath{\ge}0$ (ii) ${w}_{x}\ensuremath{\le}\ensuremath{-}1$ $\ensuremath{\xi}\ensuremath{\le}0$, where ${w}_{x}$ is the equation state $\ensuremath{\xi}$ coupling strength interaction. Because this separation, crucial information about cosmology phenomenology these may be lost. In a recent study, it has been shown...
Coupled dark matter--dark energy scenarios are modeled via a dimensionless parameter $\ensuremath{\xi}$, which controls the strength of their interaction. While this coupling is commonly assumed to be constant, there no underlying physical law or symmetry that forbids time-dependent $\ensuremath{\xi}$ parameter. The most general and complete interacting between two sectors should therefore allow for such possibility, it main purpose study constrain possible well-motivated coupled cosmologies...
Interacting dark energy models are widely renowned for giving an explanation to the cosmic coincidence problem as well several observational issues. According recent data, and so far we concerned with literature, choice of interaction function between matter is always questionable since there no such underlying theory that could derive it. Thus, in this work have raised issue by proposing two new nonlinear functions constrain them using microwave background (CMB) from Planck 2018, baryon...
Cosmological models describing the nongravitational interaction between dark matter and energy are based on some phenomenological choices of rates energy. There is no such guiding rule to select interaction. In present work we show that various might have a strong field theoretical ground. We explicitly derive several well known functions under special conditions finally constrain them using latest cosmic microwave background observations from final Planck legacy release together with baryon...
Recent measurements of the Cosmic Microwave Anisotropies power spectra measured by Planck satellite show a preference for closed universe at more than $99 \%$ Confidence Level. Such scenario is however in disagreement with several low redshift observables, including luminosity distances Type Ia Supernovae. Here we that Interacting Dark Energy (IDE) models can ease discrepancies between and Supernovae data Universe. Therefore IDE cosmologies remain as very appealing scenarios, they provide...