Abstract

The standard thin-wall approximation in Coleman-de Luccia (CdL) instanton is shown to fail at least in one modified model of gravity: the Eddington-inspired Born-Infeld (EiBI) theory. Here we apply the thin-wall approximation to the EiBI-scalar action and show that the resulting bounce gives negative-definite results even with the vanishing EiBI nonlinearity constant \(\kappa\). In contrast, the full numerical thick-wall investigation yields physically acceptable results, with a smaller bounce as compared to the original CdL. Here we also show that a regular instanton as well as its neck features can be obtained without having to resort to the method of potential reconstruction discussed previously in the literature. Finally, we also discuss tunneling from de Sitter to Minkowski as well as to anti-de Sitter.

中文翻译：

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EiBI Gravity中的CdL Instanton和薄壁近似的失败

摘要

Coleman-de Luccia (CdL) 瞬子中的标准薄壁近似至少在一种改进的引力模型中失败：受爱丁顿启发的 Born-Infeld (EiBI) 理论。在这里，我们将薄壁近似应用于 EiBI 标量动作，并表明即使 EiBI 非线性常数\(\kappa\)消失，所产生的反弹也会给出负定结果。相比之下，完整的数值厚壁研究产生了物理上可接受的结果，与原始 CdL 相比，反弹较小。在这里，我们还表明，无需借助先前在文献中讨论过的潜在重建方法，即可获得规则瞬间子及其颈部特征。最后，我们还讨论了从 de Sitter 到 Minkowski 以及到 anti-de Sitter 的隧道。