We introduce a very early universe model based on the thermodynamics of a gas of closed strings in a background that is nonperturbative in ${\alpha }^{\prime }$. Upon considering the fully ${\alpha }^{\prime }$-corrected equations extended to include certain anisotropic cosmological backgrounds, we describe the evolution of the system in three different stages parametrized by the gas’s equation of state. Using standard string thermodynamical arguments, we start with an isotropic ten-dimensional universe inside the string scale and evolve it toward a universe with four large spacetime dimensions and six stabilized internal dimensions in the Einstein frame.

中文翻译：

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经典弦几何的弦宇宙学背景

我们介绍了一个非常早期的宇宙模型，该模型基于封闭弦线气体在不扰动的背景下的热力学。 ${\alpha }^{\prime }$。经过充分考虑${\alpha }^{\prime }$校正方程扩展到包括某些各向异性宇宙学背景，我们描述了由气体状态方程参数化的系统在三个不同阶段的演化。使用标准的弦热力学参数，我们从弦尺度内的各向同性十维宇宙开始，并将其演化为在爱因斯坦框架中具有四个大时空维度和六个稳定内部维度的宇宙。