# Stable exponential cosmological solutions with three different Hubble-like parameters in EGB model with a $\\Lambda$-term

Source: [Stable exponential cosmological solutions with three different Hubble-like parameters in EGB model with a $\\Lambda$-term](<https://www.sota2.com/research/paper/68fa3c771e209131ce8dad1d>)

Collection index: [llms.txt](<https://www.sota2.com/research/llms.txt>)

Data updated: 2025-10-27T04:04:17.802Z

Authors: K. K. Ernazarov, V. D. Ivashchuk

Published: 2019-06-25T08:54:22.000Z

## Abstract

We consider a $D$-dimensional Einstein-Gauss-Bonnet model with a cosmological term $\\Lambda$ and two non-zero constants: $\\alpha\_1$ and $\\alpha\_2$. We restrict the metrics to be diagonal ones and study a class of solutions with exponential time dependence of three scale factors, governed by three non-coinciding Hubble-like parameters: $H \\neq 0$, $h\_1$ and $h\_2$, obeying $m H + k\_1 h\_1 + k\_2 h\_2 \\neq 0$ and corresponding to factor spaces of dimensions $m \> 1$, $k\_1 \> 1$ and $k\_2 \> 1$, respectively ($D = 1 + m + k\_1 + k\_2$). We analyse two cases: i) $m \< k\_1 \< k\_2$ and ii) $1\< k\_1 = k\_2 = k$, $k \\neq m$. We show that in both cases the solutions exist if $\\alpha = \\alpha\_2 / \\alpha\_1 \> 0$ and $\\alpha \\Lambda \> 0$ satisfies certain restrictions, e.g. upper and lower bounds. In case ii) explicit relations for exact solutions are found. In both cases the subclasses of stable and non-stable solutions are singled out. For $m \> 3$ the case i) contains a subclass of solutions describing an exponential expansion of $3$-dimensional subspace with Hubble parameter $H \> 0$ and zero variation of the effective gravitational constant $G$. The case $H = 0$ is also considered.

## Recorded benchmark results

A research result applies to its stated dataset, split, metric and evaluation configuration. Compare like-for-like settings, preserve the metric's unit and direction, and distinguish paper-reported results from independent reproduction. The best result recorded here is not a claim of exhaustive, current global coverage.

## Original sources and implementation

[Original paper](<https://arxiv.org/abs/1906.10391>)

[PDF](<https://arxiv.org/pdf/1906.10391.pdf>)