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arXiv 2409.18802hep-thgr-qc
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球对称下 dRGT 无幽灵大质量引力的动力学

Dynamics of dRGT ghost-free massive gravity in spherical symmetry

Emma Albertini, Jan Kożuszek, Toby Wiseman

AI总结:

本文研究了小引力子质量极限下球对称 dRGT 大质量引力的动力学,发现最小模型缺乏 Vainshtein 机制且解存在奇点,次最小模型虽有 Vainshtein 机制但对中心物质压力的限制与合理唯象学相悖,表明现实唯象学需解决奇异性或超越球对称设定。

摘要:

我们关注小引力子质量极限下球对称中的 dRGT 大质量引力。首先,我们检验了最小模型。该模型在球对称下不展现 Vainshtein 机制,但人们仍可探究球对称动力学会发生什么。我们证明,除非物质具有足够大的压力,否则不存在正则的含时球对称解。对于不满足此条件的物质,如非相对论性物质,此类解的任意 Cauchy 切片必然存在度规变为奇异的点。我们仅对渐近行为作了弱假设。接着,我们考虑次最小模型。已有论证指出,只要最小与次最小质量项的相对符号相同,该模型在球对称下便具有良好的 Vainshtein 机制,从而在唯象上可行,我们将研究限定于此情形。我们发现,正则行为要求对称中心处的物质具有正压力——特别是,有质量标量场无法满足该条件。此外,它对非相对论性物质施加了限制,使得压力在密度和引力子质量方面存在下界,且其方式与合理的唯象学相悖。这表明,现实的唯象学要么需要解决奇异性问题,要么需要超越球对称这一非普适设定的动力学。

英文摘要:

We focus on dRGT massive gravity in spherical symmetry in the limit of small graviton mass. Firstly we examine the minimal model. This does not exhibit a Vainshtein mechanism in spherical symmetry, but one may still ask what happens for spherical dynamics. We show that there are no regular time-dependent spherically symmetric solutions unless the matter has sufficiently large pressure. For matter that does not satisfy this, such as non-relativistic matter, any Cauchy slice of such a solution must necessarily have a point where the metric becomes singular. Only a weak assumption on the asymptotics is made. We then consider the next-to-minimal model. This has been argued to have a good Vainshtein mechanism in spherical symmetry, and hence be phenomenologically viable, provided the relative sign of the minimal and next-to-minimal mass terms is the same, and we restrict attention to this case. We find that regular behaviour requires the matter at the origin of symmetry to have positive pressure -- in particular a massive scalar field fails to satisfy this condition. Furthermore it restricts non-relativistic matter so that the pressure is bounded from below in terms of the density and graviton mass in a manner that is at odds with a reasonable phenomenology. This suggests that realistic phenomenology will either require a resolution of singularities, or will require dynamics beyond the non-generic setting of spherical symmetry.

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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