Modified Bekenstein-Hawking System in f(R) Gravity

Abstract

The present work deals with four alternative formulation of Bekenstein system on event horizon in f (R) gravity. While thermodynamical laws holds in universe bounded by apparent horizon, these laws break down on event horizon. With alternative formulation of thermodynamical parameters (temperature and entropy), thermodynamical laws hold on event horizon in Einstein Gravity. With this motivation, we extend the idea of generalised Hawking temperature and modified Bekenstein entropy in homogeneous and isotropic model of universe on event horizon and examine whether thermodynamical laws hold in f(R) gravity.Specifically, we examine and compare validity of generalised second law of thermodynamics (GSLT) and thermodynamical equilibrium (TE) in four alternative modified Bekenstein scenarios. As Dark energy is a possible dominant candidate for matter in the univerese and Holographic Dark Energy (HDE) can give effective description of f(R) gravity, so matter in the universe is taken as in the form interacting HDE. In order to understand the complicated expressions, finally the above laws are examined from graphical representation using three Planck data sets and it is found that generalised/modified Hawking temperature has a crucial role in making perfect thermodynamical system. equilibrium, modified Bekenstien entropy and generalised/ modified Hawking temperature, event horizon.

Segregation of tetracarbon units in low‐energy tetracarbindane structures: Major differences from their aluminum and gallium analogs

“…The energetically most stable isomers were further optimized by employing the PBE0 DFT functional and the def2-TZVP basis set. In order to refine further the energies, coupled-cluster single-point energy calculations were performed on the lowest energy isomers using the domain-based local pair-natural orbital coupled-cluster method including single and double excitations and perturbative correction for connected triples (DLPNO-CCSD[T]) [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] coupled with the def2-QZVP basis set as implemented in the ORCA 3.0.3 software package. [39][40][41][42][43][44][45][46][47] All of the resulting optimized structures were found to have substantial HOMO-LUMO gaps (cf.…”

Bound anionic states of DNA and RNA nucleobases: An EOM‐CCSD investigation

“…The initial attempts were all based on the perturbative truncation of the similarity-transformed Hamiltonian [38][39][40][41] and EOM matrix. However, the accuracy of these perturbative approximations is often not consistent and can give errors [42] as high as 0.5 eV, even for the molecules where the Hartree-Fock method gives a correct zero-order description of the reference wave function.…”

“…However, the recent back-transformed natural orbital approach [33] of Dutta et al can overcome these shortcomings and reduce the computational cost and storage requirement of the coupled cluster method without significant compromise in its accuracy.…”

“…Peng and Valeev have recently reported an efficient EOM-CCSD implementation based on state-averaged PNOs. [56] As an alternative strategy, Neese and coworkers [33] have persuaded back-transformed PNO approach (bt-PNO). In this approach after the solution of the ground state DLPNO-CCSD equations,T amplitudes are back-transformed to canonical basis, and the EOM part is calculated in the canonical basis.…”

“…The study of bound anionic state requires a large and flexible basis set, which is difficult to use in standard EOM-CCSD calculations owing to their prohibitively high cost. However, the recent developments [33] in local correlation-based EOM-CCSD method [34,35] have made it possible to calculate electron affinities of large molecules with systematically controllable accuracy. The aim of this article is to study the bound anionic states of NAB using the local correlation-based EOM-CCSD method and flexible basis sets.…”