# Anisotropic Multiverse with Varying c and G and Study of Its Thermodynamics

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Anisotropic Model of the Universe

## 3. Singularities

- Type I (Big Rip) [22]: For $t\to {t}_{s}$, $a\to \infty $, $b\to \infty $, $\rho \to \infty $ and $\left|p\right|\to \infty $.
- Type II (sudden future) [23]: For $t\to {t}_{s}$, $a\to {a}_{s}$, $b\to {b}_{s}$, $\rho \to {\rho}_{s}$ and $\left|p\right|\to \infty $.
- Type III (finite scale factors) [24]: $t\to {t}_{s}$, $a\to {a}_{s}$, $b\to {b}_{s}$, $\rho \to \infty $ and $\left|p\right|\to \infty $.
- Type IV (Big Separation) [24]: For $t\to {t}_{s}$, $a\to {a}_{s}$, $b\to {b}_{s}$, $\rho \to 0$ and $\left|p\right|\to 0$.
- Type V (w-singularity) [25]: For $t\to {t}_{s}$, $a\to {a}_{s}$, $b\to {b}_{s}$, $\rho \to 0$, $\left|p\right|\to 0$, $w=p/\rho \to \infty $.
- Type VI (Little Rip) [26]: For $t\to \infty $, $a\to \infty $, $b\to \infty $, $\rho \to \infty $ and $\left|p\right|\to \infty $.

## 4. Regularizing Strong Singularity with Varying $\mathit{G}$

#### 4.1. Regularizing Big Bang Singularity: Sine Model

#### 4.2. Regularizing Big Bang and Big Rip Singularities: Tangent Model

## 5. Thermodynamics in the Multiverse

#### 5.1. Thermodynamics for Varying c

#### 5.2. Thermodynamics for Varying G

#### 5.3. Thermodynamics for Varying c and G

## 6. Discussions and Concluding Remarks

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

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**MDPI and ACS Style**

Debnath, U.; Nag, S.
Anisotropic Multiverse with Varying *c* and *G* and Study of Its Thermodynamics. *Universe* **2022**, *8*, 398.
https://doi.org/10.3390/universe8080398

**AMA Style**

Debnath U, Nag S.
Anisotropic Multiverse with Varying *c* and *G* and Study of Its Thermodynamics. *Universe*. 2022; 8(8):398.
https://doi.org/10.3390/universe8080398

**Chicago/Turabian Style**

Debnath, Ujjal, and Soumak Nag.
2022. "Anisotropic Multiverse with Varying *c* and *G* and Study of Its Thermodynamics" *Universe* 8, no. 8: 398.
https://doi.org/10.3390/universe8080398