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arXiv 1407.0879hep-thgr-qcquant-ph
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常曲率空间中Robin球的Wightman函数和Casimir效应

Wightman function and the Casimir effect for a Robin sphere in a constant curvature space

S. Bellucci, A. A. Saharian, N. A. Saharyan

摘要:

在常负曲率空间背景下,计算了球壳上具有Robin边界条件的标量场的Wightman函数、能量动量张量的平均场平方和真空期望值.对于边界条件中的系数,存在一个临界值,超过该临界值,标量真空变得不稳定。在内部和外部区域,VEV分解为边界自由和球诱导的贡献。对于后者,提供了快速收敛的积分表示。在球内区域,特征值表示为相应Legendre函数及其导数的组合的零点,并利用这些零点上级数的Abel-Plana型求和公式实现分解.球对场平方的VEV的贡献对于Dirichlet边界条件为负,对于Neumann边界条件为正。当距球的距离大于背景空间的曲率尺度时,负曲率空间对应的引力场对真空涨落的抑制比闵可夫斯基体的情况更强。特别地,对于有质量场和无质量场,VEV随距离的衰减都是指数的。相应的结果推广到具有球形泡的空间和具有负曲率空间的宇宙模型。

英文摘要:

We evaluate the Wightman function, the mean field squared and the vacuum expectation value (VEV) of the energy-momentum tensor for a scalar field with Robin boundary condition on a spherical shell in the background of a constant negative curvature space. For the coefficient in the boundary condition there is a critical value above which the scalar vacuum becomes unstable. In both interior and exterior regions, the VEVs are decomposed into the boundary-free and sphere-induced contributions. For the latter, rapidly convergent integral representations are provided. In the region inside the sphere, the eigenvalues are expressed in terms of the zeros of the combination of the associated Legendre function and its derivative and the decomposition is achieved by making use of the Abel-Plana type summation formula for the series over these zeros. The sphere-induced contribution to the VEV of the field squared is negative for Dirichlet boundary condition and positive for Neumann one. At distances from the sphere larger than the curvature scale of the background space the suppression of the vacuum fluctuations in the gravitational field corresponding to the negative curvature space is stronger compared with the case of the Minkowskian bulk. In particular, the decay of the VEVs with the distance is exponential for both massive and massless fields. The corresponding results are generalized for spaces with spherical bubbles and for cosmological models with negative curvature spaces.

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