标题： 常声速及其在$f(Q)$引力中的热力学解释 显示英文标题

标题： Constant sound speed and its thermodynamical interpretation in $f(Q)$ gravity

摘要： 基于均匀各向同性的弗里德曼-勒梅特-罗伯逊-沃尔克（FLRW）几何，正在 $f\left( Q\right)$ 引力背景下提出解决宇宙加速膨胀和暗能量问题的方案。我们考虑一个幂律 $f(Q)$ 模型，使用 $f\left( Q\right) =\alpha Q^{n}$，其中 $\alpha $ 和 $n$ 是自由模型参数。 在当前的情景中，我们可以通过应用恒定声速参数化方法来建立我们的$f(Q)$宇宙模型的能量密度和压强，即，$\vartheta_{s}^{2}=\beta$，其中一种流体动力学宇宙流体是用$\beta$来描述的。 然后推导出场方程，并建立了它们的精确解。 我们使用包含31个数据点的更新后的哈勃（Hz）数据集、最近发布的Pantheon样本（SNe）的1048个点以及重子声学振荡（BAO）数据集来获得模型参数的约束。 我们还研究了减速参数、状态方程（EoS）参数、状态寻找诊断和Om诊断的物理行为。 我们得出结论，我们的$f\left( Q\right) $宇宙模型预测宇宙从减速到加速的转变。 此外，为了研究该模型的可行性，我们讨论了其一些热力学方面。 显示英文摘要

摘要： On the basis of homogeneous and isotropic Friedmann-Lemaitre-Robertson-Walker (FLRW) geometry, solutions to the issues of cosmic acceleration and dark energy are being put forth within the context of $f\left( Q\right)$ gravity. We take into account a power law $f(Q)$ model using $f\left( Q\right) =\alpha Q^{n}$, where $\alpha $ and $n$ are free model parameters. In the current scenario, we may establish the energy density and pressure for our $f(Q)$ cosmic model by applying the constant sound speed parameterizations, i.e., $\vartheta_{s}^{2}=\beta$, where a barotropic cosmic fluid is described in terms of $\beta$. The field equations are then derived, and their precise solutions are established. We obtain the constraints on the model parameters using the updated Hubble (Hz) data sets consisting of 31 data points, the recently published Pantheon samples (SNe) with 1048 points, and Baryon acoustic oscillations (BAO) data sets. We also examine the physical behaviour of the deceleration parameter, the equation of state (EoS) parameter, the statefinder diagnostic, and the Om diagnostic. We conclude that our $f\left( Q\right) $\ cosmic model predicts a transition in the universe from deceleration to acceleration. Further, to investigate the feasibility of the model, we discussed some of its thermodynamic aspects.