We apply the optimized perturbation theory (OPT) to resum the perturbative series describing the mass gap of the bidimensional ϕ⁴ theory in the ℤ₂ symmetric phase. Already at NLO (one loop) the method is capable of generating a quite reasonable non-perturbative result for the critical coupling. At order-g⁷ we obtain g_c = 2.779(25) which compares very well with the state of the art N⁸LO result, g_c = 2.807(34). As a novelty we investigate the supercritical region showing that it contains some useful complimentary information that can be used in extrapolations to arbitrarily high orders.

A preprint version of the article is available at ArXiv.

中文翻译：

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二维标量理论的临界行为：恢复 N8LO 微扰质量间隙

我们应用优化微扰理论 (OPT) 来恢复描述ℤ ₂对称相中二维ϕ ⁴理论质量间隙的微扰级数。已经在 NLO（一个循环）中，该方法能够为临界耦合生成相当合理的非微扰结果。在阶g ⁷我们得到g _c = 2 。779(25) 与最先进的 N ⁸ LO 结果相比非常好，g _c = 2 。807(34)。作为一项新颖性，我们研究了超临界区域，表明它包含一些有用的补充信息，可用于外推到任意高阶。

该文章的预印版可在 ArXiv 上获得。