This paper reveals about a stable flat cosmological model which has been constructed, and the evolution of dark energy has been investigated in the framework of the recently suggested non-Lagrangian \(\kappa (R,T)\) modified gravity (Terule, Eur Phys J C 78:660, 2018). The toy model we are presenting in the current work reveals some interesting cosmological features consistent with observations and the standard \(\Lambda \)CDM model. The evolution of cosmic pressure shows a positive-to-negative transition corresponding to the cosmic deceleration–acceleration transition. Both the deceleration parameter and the cosmic pressure have the positive-to-negative sign flipping. While this behavior can provide explanation for the deceleration–acceleration transition, the reason behind this positive-negative transition itself is still missing. The current model implies a very small positive value for the cosmological constant which also agrees with observations.

本文揭示了一个已建立的稳定的平面宇宙学模型，并在最近提出的非拉格朗日\（\ kappa（R，T）\）修正引力（Terule，Eur ）的框架下研究了暗能量的演化Phys JC 78：660，2018）。我们在当前工作中展示的玩具模型揭示了一些有趣的宇宙学特征，这些特征与观测结果和标准\（\ Lambda \）一致CDM模型。宇宙压力的演化显示出正负过渡，对应于宇宙减速-加速过渡。减速参数和宇宙压力都具有正负符号翻转。尽管这种行为可以为减速-加速过渡提供解释，但这种正负过渡本身背后的原因仍然缺失。当前模型暗示宇宙常数的极小正值，这也与观察结果一致。