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Nandhida Krishnan. P

Publications and source records attributed to Nandhida Krishnan. P.

2 recordsLinked to original sources

Emergence of cosmic space with Barrow entropy, in non-equilibrium thermodynamic conditions

Recently, Barrow accounts for the quantum gravitational effects to the black hole surface. Thus the conventional area-entropy relation has modified, $S=(A/A_{0})^{1+Δ/2},$ with an exponent $Δ$, ranges $0\leΔ\le1$, quantifies the amount of quantum gravitational deformation effect to the black hole surface. In recent literature, this horizon entropy has been extended to the cosmological context. Following this, we consider an n+1 dimensional non-flat universe with an apparent horizon as the boundary with appropriate temperature and associated entropy is Barrow entropy. We derived the modified form of the law of emergence from the equilibrium and non-equilibrium thermodynamic principles. Later studied the entropy maximization condition due to the modified law of emergence. On distinguishing the obtained result, it speculates that in order to hold the energy-momentum conservation, the universe with Barrow entropy as the horizon entropy should have non-equilibrium behaviour with an additional entropy production. However, the additional entropy production rate decreases over time, so the system eventually approaches equilibrium. Because of this, the constraint relation for entropy maximization looks similar for both equilibrium and non-equilibrium approaches.

gr-qc

Barrow Holographic Dark Energy Model with GO Cut-off -- An Alternative Perspective

Recently, Barrow holographic dark energy (BHDE), based on Barrow entropy, has been proposed to describe the late acceleration of the universe. Contrary to the earlier analysis of this model in the literature, we consider the BHDE with the Granda-Oliveros length as IR cut-off, as a dynamical vacuum, having a constant equation of state $ω_Λ=-1.$ We have analytically solved for the Hubble parameter and studied the evolution of cosmological parameters. The model is compared with the observational data on Hubble parameter (OHD36) and Supernovae type Ia (SN Ia), the pantheon data. In the absence of interaction between the dark sectors, we found that the model predicts a $Λ$CDM like evolution of the universe with an effective cosmological constant. In this case, the model is found to satisfy the generalized second law (GSL), irrespective of the value of the Barrow index. The interaction also shows the safe validity of GSL, for the extracted value of the Barrow index, $Δ=0.063\pm 0.029$. The thermodynamic analysis of the model predicts an end de Sitter phase of maximum entropy. We performed a dynamical system analysis, which reveals that the end de Sitter phase is stable. Furthermore, we performed the Information Criterion analysis using Akaike and Bayesian Information Criterion to compare the statistical compatibility of the present model with the standard $Λ$CDM model.

gr-qc