In this work, LRS Bianchi type-I cosmological model with perfect fluid source in [Formula: see text] gravity theory, where [Formula: see text] is the Ricci scalar and [Formula: see text] is the trace of the stress energy-momentum tensor, has been studied in order to investigate early time deceleration and late time acceleration of the universe. By proposing a new special form of time-varying deceleration parameter in terms of Hubble parameter, the exact solution of the field equations has been obtained. The physical and geometric quantities of the model have been derived and their evolution has been discussed. Our model has an initial singularity and initially exhibits decelerating expansion and transits to accelerating expansion phase at last eras. The nature of the matter source of the model is consistent with the standard model in frame of the structure formation.

中文翻译：

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LRS Bianchi I 型宇宙学模型在 f(R,T) 引力下的相变

本工作采用[公式：见文]引力理论中具有完美流体源的LRS Bianchi I型宇宙学模型，其中[公式：见文]为里奇标量，[公式：见文]为应力能量的迹线-动量张量，已被研究以研究宇宙的早期减速和晚期加速。根据哈勃参数提出一种新的特殊形式的时变减速参数，得到了场方程的精确解。模型的物理量和几何量已经推导出来，并讨论了它们的演变。我们的模型有一个初始奇点，最初表现出减速扩张，并在最后一个时代过渡到加速扩张阶段。