The principal goal of the present paper is to study rarefied relativistic polyatomic gases in both Minkowski spacetime and Robertson–Walker spacetime. The field equations are determined from a recently developed generalized relativistic BGK-type model for polyatomic gases. This model is applied to both Minkowski spacetime and flat and non- flat Robertson–Walker spacetimes. The equation of state for the non-equilibrium dynamical pressure is obtained from the Chapman–Enskog method applied to a variant of the Anderson and Witting model for polyatomic gases.

中文翻译：

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引力场中的稀薄相对论多原子气体

本论文的主要目标是研究 Minkowski 时空和 Robertson-Walker 时空中的稀有相对论多原子气体。场方程由最近开发的多原子气体广义相对论 BGK 型模型确定。该模型适用于 Minkowski 时空以及平坦和非平坦 Robertson-Walker 时空。非平衡动态压力的状态方程是从应用于多原子气体的 Anderson 和 Witting 模型的变体的 Chapman-Enskog 方法获得的。