Sourav Haldar

Formation of emergent universe in brane scenario as a consequence of particle creation

Here we formulate scenario of emergent universe from particle creation mechanism in spatially flat braneworld models. We consider an isotropic and homogeneous universe in Braneworld cosmology and universe is considered as a non-equilibrium thermodynamical system with dissipation due to particle creation mechanism. Assuming the particle creation rate as a function of the Hubble parameter, we formulate emergent scenario in RS2 and DGP models of Braneworld.

Thermodynamics of the dissipative cosmic fluid and stability criteria

Abstract.The work deals with the thermodynamical aspects of the cosmic substratum which is dissipative in nature. For the homogeneous and isotropic model of the Universe this dissipative phenomenon is an effective bulk viscous pressure in nature and is related to the particle creation mechanism. Finally, the stability criteria for the thermal equilibrium have been analyzed and are presented in tabular form restricting the particle creation parameter or the variation of the equation of state parameter with the volume.

Tunnelling Mechanism in Noncommutative Space with Generalized Uncertainty Principle and Bohr-Like Black Hole

The paper deals with non-thermal radiation spectrum by tunnelling mechanism with correction due to the generalized uncertainty principle (GUP) in the background of non-commutative geometry. Considering the reformulation of the tunnelling mechanism by Banerjee and Majhi, the Hawking radiation spectrum is evaluated through the density matrix for the outgoing modes. The GUP corrected effective temperature and the corresponding GUP corrected effective metric in non-commutative geometry are determined using Hawkings periodicity arguments. Thus, we obtain further corrections to the non-strictly thermal black hole (BH) radiation spectrum which give new final distributions. Then, we show that the GUP and the non-commutative geometry modify the Bohr-like BH recently discussed in a series of papers in the literature. In particular, we find the intriguing result that the famous law of Bekenstein on the area quantization is affected neither by non-commutative geometry nor by the GUP. This is a clear indication of the universality of Bekensteins result. In addition, we find that both the Bekentsein-Hawking entropy and the total BH entropy to third order approximation are still functions of the BH quantum level.

A thermodynamical analysis of the inhomogeneous FLRW type model: Redefined Bekenstein–Hawking system

A detailed thermodynamical study has been presented for the inhomogeneous FLRW-type model of the Universe bounded by a horizon with three possible modifications of Bekenstein–Hawking formulation of thermodynamical parameters namely entropy and temperature. For the first choice of the thermodynamical system validity of both the first law of thermodynamics (FLT) and the generalized second law of thermodynamics (GSLT) are examined. Also, the integrability conditions for the exact one-forms in both the thermodynamical laws are analyzed and it is found that they are consistent with each other. On the other hand, for the other two choices of the thermodynamical system to hold the first law of thermodynamics, one must restrict the parameters (in the definition of the thermodynamical variables) in some specific integral form.

Emergent Scenario in first and second order non-equilibrium thermodynamics and stability analysis

First and second order non-equilibrium thermodynamics are studied in the context of particle creation mechanism for homogeneous and isotropic FLRW model and a general formulation of the emergent scenario is investigated. Finally, the stability of the non-equilibrium thermodynamics is examined.