39 citations · 51 across the 10 of their papers we have counts for
15 papers
Stability Analysis of Axion Dark Energy Model
Ankan Mukherjee, Nandan Roy
We investigate the stability of an axion dark energy model characterized by a periodic scalar-field potential motivated by pseudo Nambu Goldstone bosons. While such models are well…
Kruglov-entropy cosmology from apparent-horizon thermodynamics: background dynamics and observational constraints
Candrasyah Muhammad, Burin Gumjudpai, Nandan Roy +1
We investigate two late-time cosmological models generated by Kruglov's nonadditive entropy at the apparent horizon. Model I, originally derived by Kruglov, follows the Cai--Kim th…
Observational constraints on scalar-vector-tensor dark energy with phantom-divide crossing
Nandan Roy, Shinji Tsujikawa, Ying-li Zhang +1
We constrain a scalar-vector-tensor (SVT) dark-energy model in which the vector sector drives the dark-energy equation of state below at earlier times, while a canonical scala…
The role of anisotropy in gravity: insights from cosmological observations
Ghulam Murtaza, Nandan Roy, Avik De
We investigate the cosmological dynamics of Bianchi-I spacetime in symmetric teleparallel gravity through a dynamical system approach to analyse observational constraints. B…
-CDM: A Minimal Deformation of CDM with Scalar Field Reconstruction
Phichayoot Baisri, Nandan Roy, Prasanta Sahoo +2
Recent DESI BAO observations provide intriguing hints that dark energy may be dynamical in nature. To investigate deviations of the dark energy equation of state (EoS) from $w = -1…
CosmoDS: A Python toolkit for constraining cosmological models via dynamical systems analysis with Cobaya
Nandan Roy, Prasanta Sahoo
We present a toolkit, CosmoDS, designed to study cosmological models at the background level using dynamical system analysis within the Cobaya framework. Dynamical system analysis…
Dynamical Systems in Cosmology: Reviewing An Alternative Approach
Nandan Roy, L. Arturo Ureña-López
Dark energy is one of the deepest puzzles in modern cosmology, and mounting evidence suggests that it is not just a cosmological constant but a genuinely dynamical component. Altho…
Chiellini-Integrable Cosmologies with Phantom Divide Crossing
Soumya Chakrabarti, Nandan Roy
We investigate exact cosmological solutions with a massive scalar field minimally coupled to the Einstein-Hilbert action in General Relativity. For an extended Higgs-like scalar se…
Quintom Dark Energy: Future Attractor and Phantom Crossing in Light of DESI DR2 Observation
Phusuda Thanankullaphong, Prasanta Sahoo, Prajwal Hassan Puttasiddappa +1
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 FLR…
Is Phantom Barrier Crossing Inevitable? A Cosmographic Analysis
Nandan Roy, Soumya Chakrabarti
Recent findings from the Dark Energy Spectroscopic Instrument (DESI), analyzed together with supernova observations and CMB measurements, provide statistically significant indicati…
Constraints on DBI dark energy with chameleon mechanism
Burin Gumjudpai, Nandan Roy, John Ward
In this work, we investigate the Dirac--Born--Infeld (DBI) scalar field model with and without the inclusion of the chameleon mechanism in light of the latest cosmological observat…
Quintessence scalar field and cosmological constant: Dynamics of a multi-component dark energy model
Prasanta Sahoo, Nandan Roy, Himadri Shekhar Mondal
This study explores the dynamics and phase-space behavior of a multi-component dark energy model, where the dark sector consists of a minimally coupled canonical scalar field and t…
-- interacting scalar tensor dark energy
Masroor C. Pookkillath, Nandan Roy
We study the effect of adding an interaction in the term of Horndeski theory, where the propagation of gravitational waves are not modified. We derive the background and pert…
Dynamical dark energy in the light of DESI 2024 data
Nandan Roy
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…
Tracker behaviour of quintom dark energy and the Hubble tension
Nandan Roy, L Arturo Ureña-López
We study the dynamics of the quintom dark energy model using state-of-the-art cosmological observations. The set of equations has been converted into an autonomous system using sui…