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arXiv 2402.18604gr-qcastro-ph.CO
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非平坦FLRW宇宙中具有表观视界截断与非最小导数耦合引力的全息暗能量动力学

Dynamics of holographic dark energy with apparent-horizon cutoff and non-minimal derivative coupling gravity in non-flat FLRW universe

Amornthep Tita, Burin Gumjudpai, Pornrad Srisawad

AI总结:

本文研究非平坦FLRW宇宙中非最小导数耦合引力与表观视界截断全息暗能量的动力学,通过稳定性分析发现一个对应de-Sitter膨胀的稳定不动点,并结合H(z)数据表明负NMDC耦合和大全息贡献可产生幻影状态方程。

摘要:

本文考虑了包含物质、在幂律势下与爱因斯坦张量非最小导数耦合的标量场以及全息真空能量的宇宙背景动力学。全息红外截断尺度取为表观视界,对于加速宇宙而言,表观视界以与黑洞事件视界相同的精神形成一个俘获零曲面。在非平坦情形下,有效引力常数无法在Friedmann方程中表达。因此,全息真空密度用标准引力常数而非有效引力常数来定义。动力学与稳定性分析显示存在四个独立的不动点。其中一个不动点是稳定的,对应于$w_{\ ext{eff}} = -1$。稳定不动点解的一个分支对应于de-Sitter膨胀。其余不动点要么是不稳定的,要么是鞍点。对动力学系统进行了数值积分,并与$H(z)$数据进行了对比绘图。结果发现,对于平坦宇宙,$H(z)$观测数据倾向于较大的负NMDC耦合参数$κ$值。较大的全息贡献$c$和较大的负NMDC耦合会增加$w_{\ ext{eff}}$和$H(z)$的斜率与幅度。负的$κ$可以贡献幻影状态方程,即$w_{\ ext{eff}} < -1$。NMDC与空间曲率的耦合可能具有幻影能量贡献。自由负空间曲率项也可以贡献幻影状态方程,但只有在空间曲率取显著大的负值时才能实现。对于$κ= -200$和较高的$c$值,该模型在平坦和开放两种情形下都能给出幻影状态方程。

英文摘要:

Background cosmological dynamics for a universe with matter, a scalar field non-minimally derivative coupling to Einstein tensor under power-law potential and holographic vacuum energy is considered here. The holographic IR cutoff scale is apparent horizon which, for accelerating universe, forms a trapped null surface in the same spirit as blackhole's event horizon. For non-flat case, effective gravitational constant cannot be expressed in the Friedmann equation. Therefore holographic vacuum density is defined with standard gravitational constant instead of the effective one. Dynamical and stability analysis shows four independent fixed points. One fixed point is stable and it corresponds to $w_{\text{eff}} = -1$. One branch of the stable fixed-point solutions corresponds to de-Sitter expansion. The others are either unstable or saddle nodes. Numerical integrations of the dynamical system are performed and plotted confronting with $H(z)$ data. It is found that for flat universe, $H(z)$ observational data favors large negative value of NMDC coupling, $κ$. Larger holographic contribution, $c$, and larger negative NMDC coupling increase slope and magnitude of the $w_{\text{eff}}$ and $H(z)$. Negative $κ$, can contribute to phantom equation of state, $w_{\text{eff}} < -1$. The NMDC-spatial curvature coupling could have phantom energy contribution. Free negative spatial curvature term can also contribute to phantom equation of state, but only with significantly large negative value of the spatial curvature. The model could give phantom equation of state for $κ= -200$ and high value of $c$ for both flat and open cases.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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