Conical singularities and the Vainshtein screening in full GLPV theories
Conical singularities and the Vainshtein screening in full GLPV theories
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DOI：
10.1088/1475-7516/2016/03/003
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发表时间：
2015-12
影响因子：
6.4
通讯作者：
R. Kase;S. Tsujikawa;A. D. Felice
中科院分区：
文献类型：
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作者：
R. Kase;S. Tsujikawa;A. D. Felice
在Gleyzes-Langlois-Piazza-Vernizzi （GLPV）理论中，已知当表征偏离Horndeski lagrange L4的参数αH4趋近于非零常数r→0时，圆锥形奇点出现在球对称体（r = 0）的中心。我们在全GLPV理论中推导了围绕中心的球对称解，并证明了GLPV拉格朗日L5不改变非零αH4引起的Ricci标量R的发散性。在αH4 = 0的条件下，在Horndeski域以外，即使L5存在，曲率标量在r = 0处仍然是有限的。对于标量场φ直接耦合到R的理论，我们也得到了身体内外的球对称解，以研究由φ介导的第五种力是否可以通过非线性场自相互作用来筛选。我们发现有一个特定的GLPV理论模型，其中L5的影响在运动方程中消失。我们还表明，根据场方程中l5相关项的符号，该模型可以在Vainshtein机制下兼容太阳能系统约束，或者受到高密度区域场导数发散问题的困扰。
In Gleyzes-Langlois-Piazza-Vernizzi (GLPV) theories, it is known that the conical singularity arises at the center of a spherically symmetric body (r = 0) in the case where the parameter αH4 characterizing the deviation from the Horndeski Lagrangian L4 approaches a non-zero constant as r → 0. We derive spherically symmetric solutions around the center in full GLPV theories and show that the GLPV Lagrangian L5 does not modify the divergent property of the Ricci scalar R induced by the non-zero αH4. Provided that αH4 = 0, curvature scalar quantities can remain finite at r = 0 even in the presence of L5 beyond the Horndeski domain. For the theories in which the scalar field ϕ is directly coupled to R, we also obtain spherically symmetric solutions inside/outside the body to study whether the fifth force mediated by ϕ can be screened by non-linear field self-interactions. We find that there is one specific model of GLPV theories in which the effect of L5 vanishes in the equations of motion. We also show that, depending on the sign of a L5-dependent term in the field equation, the model can be compatible with solar-system constraints under the Vainshtein mechanism or it is plagued by the problem of a divergence of the field derivative in high-density regions.