English

Clouds of strings in $4D$ Einstein-Gauss-Bonnet black holes

General Relativity and Quantum Cosmology 2020-10-13 v6 High Energy Physics - Theory

Abstract

Recently it has been shown that the Einstein-Gauss-Bonnet (EGB) gravity, by rescaling the coupling constant as α/(D4)\alpha/(D-4) and taking the limit D4D \rightarrow 4 at the level of the equations of motion, becomes nontrivially ghost-free in 4D4D - namely the novel 4D4D EGB gravity. We present an exact charged black hole solution to the theory surrounded by clouds of string (CS) and also analyze their thermodynamic properties to calculate exact expressions for the black hole mass, temperature, and entropy. Owing to the corrected black hole due to the background CS, the thermodynamic quantities have also been corrected except for the entropy, which remains unaffected by a CS background. However, as a result of the novel 4D4D EGB theory, the Bekenstein-Hawking area law turns out to be corrected by a logarithmic area term. The heat capacity C+C_+ diverges at a critical radius r=rCr=r_C, where incidentally the temperature has a maximum, and the Hawking-Page transitions even in absence of the cosmological term and C+>0C_+ > 0 for r+<rCr_+ < r_C allowing the black hole to become thermodynamically stable. In addition, the smaller black holes are globally preferred with negative free energy F+<0F_+<0. Our solution can also be identified as a 4D4D monopole-charged EGB black hole. We regain results of spherically symmetric black hole solutions of general relativity and that of novel 4D4D EGB, respectively, in the limits α0\alpha \to 0 and a=0a=0.

Keywords

Cite

@article{arxiv.2003.14136,
  title  = {Clouds of strings in $4D$ Einstein-Gauss-Bonnet black holes},
  author = {Dharm Veer Singh and Sushant G. Ghosh and Sunil D. Maharaj},
  journal= {arXiv preprint arXiv:2003.14136},
  year   = {2020}
}

Comments

12 pages, 4 figures, 2 tables, Phys.Dark Univ. 30 (2020) 100730