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We consider Kaluza-Klein (KK) models where internal spaces are compact Einstein spaces. These spaces are stabilized by background matter (e.g., monopole form-fields). We perturb this background by a compact matter source (e.g., the system of gravitating masses) with the zero pressure in the external/our space and an arbitrary pressure in the internal space. We show that in the case of curved Einstein spaces, the Einstein equations are compatible only if the matter source is smeared over the internal space and perturbed metric components do not depend on coordinates of extra dimensions. The latter means the absence of KK modes corresponding to the metric fluctuations. There are two possibilities to satisfy the gravitational tests. First, the gravitating source (e.g. our Sun) should have the black string equation of state in the internal space. This result does not depend on the size of the internal space. Second, if the equation of state in the internal space is arbitrary (e.g. dust like), then the size of the internal space should be small enough and radion is very massive particle.

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Alexander Zhuk, Odessa
Conferenceroom 1 (New building)
Contact: not specified