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arXiv 0910.5243hep-phgr-qchep-th
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有无洛仑兹对称性破坏的大质量引力之谜

Resolving Puzzles of Massive Gravity with and without violation of Lorentz symmetry

Andrei Mironov, Sergey Mironov, Alexei Morozov, Andrey Morozov

摘要:

本文系统地研究了任意维中有无破坏洛伦兹对称性的大质量引力的各种形式。众所周知,这些理论具有非常不寻常的性质,从规范和洛伦兹不变模型的研究中不熟悉。这些特殊性是由熟悉的横向场与复活的纵向和纯规范(Stueckelberg)场的混合引起的,并且在二次近似中已经全部看到。它们都与非平凡的色散定律有关,这很容易允许超光速传播,鬼,快子和基本的非理性。此外,出现的模式前面的系数很小,这使得理论在大的Vainshtein半径内基本上是非微扰的。试图摆脱不必要的自由度,给他们无限的质量导致DVZ不连续性的参数(模量)空间,所造成的不可置换的不同限制。另外,条件m_{gh} = \infty在非平凡引力背景中已经不能保持,并且在线性化引力的任何其他扰动下都是不稳定的。同时,由卡鲁扎-克莱因塔的任何质量水平提供的二次近似的{ \it a priori}健康的大质量引力模型是肯定存在的。它绕过了这些问题,因为重力场与其他场混合,这解释了为什么这种混合在其他模型中有帮助。同时,这可能意味着真正健康的大质量引力仍然需要无限数量的超出二次近似的额外场。

英文摘要:

We perform a systematic study of various versions of massive gravity with and without violation of Lorentz symmetry in arbitrary dimension. These theories are well known to possess very unusual properties, unfamiliar from studies of gauge and Lorentz invariant models. These peculiarities are caused by mixing of familiar transverse fields with revived longitudinal and pure gauge (Stueckelberg) fields and are all seen already in quadratic approximation. They are all associated with non-trivial dispersion laws, which easily allow superluminal propagation, ghosts, tachyons and essential irrationalities. Moreover, coefficients in front of emerging modes are small, what makes the theories essentially non-perturbative within a large Vainshtein radius. Attempts to get rid of unwanted degrees of freedom by giving them infinite masses lead to DVZ discontinuities in parameter (moduli) space, caused by un-permutability of different limits. Also, the condition m_{gh}=\infty can not be preserved already in non-trivial gravitational backgrounds and is unstable under any other perturbations of linearized gravity. At the same time an {\it a priori} healthy model of massive gravity in quadratic approximation definitely exists: provided by any mass level of Kaluza-Klein tower. It bypasses the problems because gravity field is mixed with other fields, and this explains why such mixing helps in other models. At the same time this can imply that the really healthy massive gravity can still require infinite number of extra fields beyond quadratic approximation.

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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