AI 中文总结
研究爱因斯坦 - 嘉当宇宙学中哈勃截断全息暗能量，发现绝热挠率不能挽救哈勃半径作为红外截断产生后期加速，通过不同条件得出$\Omega_{\Phi}$的嵌套上限，其对暗能量状态方程的影响远低于DESI偏好，还指出格兰达 - 奥利沃斯截断中挠率的情况。
AI 中文摘要
在具有爱因斯坦 - 嘉当挠率的弗里德曼宇宙学中，与单独守恒的物质部分兼容的均匀挠率模式按$\Phi\propto a^{-3}$缩放，并作为负能量密度的刚性成分进入弗里德曼约束，即$-3\Phi^{2}\propto a^{-6}$。最近有人声称这种模式挽救了哈勃半径作为全息暗能量的红外截断，产生后期加速和可能与DESI相关的幻分界穿越。我们表明并非如此。对于哈勃截断，全息密度从减速参数中消失，唯一的加速阶段是在$H(\bar{a}) = 0$处挠率反弹周围的瞬态窗口$\bar{a}\leq a<4^{1/3}\bar{a}$；将该窗口置于可观测红移处会迫使哈勃率在我们最近的过去消失，这与测量的膨胀历史相悖。要求一个可行的历史会产生关于$\Omega_{\Phi}\equiv(\Phi_{0}/H_{0})^{2}$的嵌套上限：拟合官方DESI DR2 BAO似然性给出$\Omega_{\Phi}<8.7\times10^{-4}$（$95\%$置信水平），在$z = 那么，存在一个光谱确认的星系给出$8.4\times10^{-5}$，宇宙微波背景给出$3.1\times10^{-10}$，大爆炸核合成给出$5\times10^{-24}$。今天对暗能量状态方程的影响，$|1+\omega_{0}|\leq2\Omega_{\Phi}/\Omega_{\Lambda}$，在幻方一侧最多比DESI的偏好低两个数量级，最坏情况下低二十二个数量级。在格兰达 - 奥利沃斯截断中，挠率加深而非阻止大撕裂奇点。附录从爱因斯坦 - 嘉当场方程推导了弗里德曼对，并表明$a^{-3}$缩放是稀释自旋流体的运动学；逃避不可行结果需要恰好打破这一点。
英文摘要
In Friedmann cosmology with Einstein--Cartan torsion, the homogeneous torsion mode compatible with a separately conserved matter sector scales as $Φ\propto a^{-3}$ and enters the Friedmann constraint as a stiff component of negative energy density, $-3Φ^{2}\propto a^{-6}$. It has recently been claimed that this mode rescues the Hubble radius as an infrared cutoff for holographic dark energy, producing late-time acceleration and a phantom-divide crossing of possible relevance to DESI. We show that it cannot. With the Hubble cutoff the holographic density drops out of the deceleration parameter, and the only accelerating regime is the transient window $\bar{a}\leq a<4^{1/3}\bar{a}$ around the torsion bounce at $H(\bar{a})=0$; placing that window at observable redshifts would force the Hubble rate to vanish in our recent past, against the measured expansion history. Requiring a viable history yields nested upper bounds on $Ω_Φ\equiv(Φ_{0}/H_{0})^{2}$: fitting the official DESI DR2 BAO likelihood gives $Ω_Φ<8.7\times10^{-4}$ ($95\%$ CL), the existence of a spectroscopically confirmed galaxy at $z=14.32$ gives $8.4\times10^{-5}$, the CMB gives $3.1\times10^{-10}$, and Big Bang nucleosynthesis gives $5\times10^{-24}$. Today's imprint on the dark energy equation of state, $|1+ω_{0}|\leq2Ω_Φ/Ω_Λ$, falls short of the DESI preference by two orders of magnitude at best and twenty-two at worst, and on the phantom side. In the Granda--Oliveros cutoff, torsion deepens rather than prevents the big-rip singularity. An appendix derives the Friedmann pair from the Einstein--Cartan field equations and shows that the $a^{-3}$ scaling is the kinematics of a diluting spin fluid; escaping the no-go requires breaking exactly that.
