Entropy Product Function and Central charges in NUT Geometry

TL;DR

This paper introduces an entropy product function (EPF) for TNUT black holes, deriving their central charges and exploring holographic descriptions, revealing new relations between thermodynamic quantities and conformal field theory parameters.

Contribution

It defines the EPF for TNUT black holes and establishes a novel relation between central charges and the EPF derivatives, extending holographic descriptions to various NUT-charged black holes.

Findings

Derived central charges from EPF for TNUT black holes.

Established a relation c=6(∂F/∂N_i) linking central charges and EPF.

Showed multiple holographic descriptions via integer pairs (a,b).

Abstract

We define an \emph{entropy product function}~(EPF) for Taub-Newman-Unti-Tamburino~(TNUT) black hole~(BH) following the prescription suggested by Wu et al.~\cite{wu} ~[PRD 100, 101501(R) (2019)]. The prescription argues that a generic four-dimensional TNUT spacetime might be expressed in terms of three or four different types of thermodynamic hairs. They can be defined as the Komar mass~($M=m$), the angular momentum~($J_{n}=mn$), the gravitomagnetic charge ($N=n$), the dual~(magnetic) mass $(\tilde{M}=n)$. Taking this prescription and using the \emph{EPF}, we derive the \emph{central charges} of dual CFT~(conformal field theory) via Cardy's formula. Remarkably, we \emph{find} that for TNUT BH there exists a relation between the \emph{central charges and EPF} as $c=6\left(\frac{\partial {\cal F}}{\partial {\cal N}_{i}}\right)$, where ${\cal F}$ is EPF and ${\cal N}_{i}$ is one of the integer-valued charges i.e. the NUT charges~($N$) or any new conserved charges~($J_{N}$). We reverify these results by calculating the exact values of different thermodynamic parameters. We define the EPF~${\cal F}$ from the first law of thermodynamics of both horizons. Moreover, we write the first laws of both the horizons for left-moving and right-moving sectors. Introducing the B\'{e}zout's identity, we show that for TNUT BH one can generate more holographic descriptions described by a pair of integers $(a,b)$. More holographic pictures have a great significance in understanding the holographic nature of quantum gravity. Furthermore, using the \emph{EPF} we derive the central charges for Reissner-Nordstr\"{o}m-NUT~(RNNUT) BH, Kerr-Taub-NUT~(KNUT) BH and Kerr-Newman-NUT~(KNNUT) BH. Finally, we prove that they are equal in both sectors provided that the EPF is mass-independent~(or universal).