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arXiv 2406.02689astro-ph.CO
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宇宙的几何再加热

Geometric reheating of the Universe

Daniel G. Figueroa, Nicolas Loayza

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39 pages, 18 figures
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AI总结：

通过晶格模拟研究几何预热非线性区域，探讨暴胀子向非最小耦合标量场能量转移，发现再加热效率随势指数$p$增加而提升，并受自相互作用和暴胀尺度影响。

摘要：

我们研究了暴胀后能量从暴胀子（$ϕ$）向通过$ξR|χ|^2$与引力非最小耦合的标量场（$χ$）的转移，考虑了在$ϕ= 0$附近具有暴胀子势$V_{\rm inf} \propto |ϕ|^{\\,p}$的模型。这对应于几何预热（geometric preheating）范式，我们通过晶格模拟将其扩展至非线性区域。以$α$-吸引子T模型势作为代理，我们研究了$p=2, 4, 6$时实现适当再加热的可行性，确定了能否实现由$χ$能量主导$ϕ$而产生的辐射主导（RD）。对于大的暴胀尺度$Λ$，$p = 2$时再加热受阻，$p = 4$时可部分实现，$p = 6$时变得非常高效。然而，如果$χ$维持自相互作用（除非极其微弱），或者$Λ$足够低使得暴胀子碎裂导致宇宙迅速进入RD，高效的再加热会被阻断。无论是由再加热还是暴胀子碎裂实现RD，我们都刻画了该问题的能量和时间尺度，作为$Λ$和$ξ$的函数。

英文摘要：

We study the post-inflationary energy transfer from the inflaton ($ϕ$) into a scalar field ($χ$) non-minimally coupled to gravity through $ξR|χ|^2$, considering models with inflaton potential $V_{\rm inf} \propto |ϕ|^{\,p}$ around $ϕ= 0$. This corresponds to the paradigm of {\it geometric preheating}, which we extend to its non-linear regime via lattice simulations. Considering $α$-attractor T-model potentials as a proxy, we study the viability of proper {\it reheating} for $p=2, 4, 6$, determining whether radiation domination (RD) due to energetic dominance of $χ$ over $ϕ$, can be achieved. For large inflationary scales $Λ$, reheating is frustrated for $p = 2$, it can be partially achieved for $p = 4$, and it becomes very efficient for $p = 6$. Efficient reheating can be however blocked if $χ$ sustains self-interactions (unless these are extremely feeble), or if $Λ$ is low enough, so that inflaton fragmentation brings the universe rapidly into RD. Whenever RD is achieved, either due to reheating or to inflaton fragmentation, we characterize the energy and time scales of the problem, as a function of $Λ$ and $ξ$.

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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