We analyse spatially homogenous cosmological models of locally rotationally symmetric Bianchi type III with a massive scalar field as matter model. Our main result concerns the future asymptotics of these spacetimes and gives the dominant time behaviour of the metric and the scalar field for all solutions for late times. This metric is forever expanding in all directions, however in one spatial direction only at a logarithmic rate, while at a power-law rate in the other two. Although the energy density goes to zero, it is matter dominated in the sense that the metric components differ qualitatively from the corresponding vacuum future asymptotics. Our results rely on a conjecture for which we give strong analytical and numerical support. For this we apply methods from the theory of averaging in nonlinear dynamical systems. This allows us to control the oscillations entering the system through the scalar field by the Klein-Gordon equation in a perturbative approach.

中文翻译：

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具有大量标量场的局域旋转对称 Bianchi III 型宇宙学的振荡和未来渐近性

我们分析了局部旋转对称 Bianchi III 型的空间同质宇宙学模型，并以大量标量场作为物质模型。我们的主要结果涉及这些时空的未来渐近性，并给出了度量的主要时间行为和所有后期解的标量场。该度量永远向所有方向扩展，但是在一个空间方向仅以对数速率扩展，而在其他两个方向以幂律速率扩展。尽管能量密度变为零，但从度量分量与相应的真空未来渐近线在性质上不同的意义上说，它是物质主导的。我们的结果依赖于一个猜想，我们对此给出了强有力的分析和数值支持。为此，我们应用非线性动力系统中的平均理论中的方法。