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タイトル: | Multi-scalar theories of gravity with direct matter couplings and their parametrized post-Newtonian parameters |
著者: | Lacombe, Osmin Mukohyama, Shinji |
著者名の別形: | 向山, 信治 |
キーワード: | modified gravity particle physics - cosmology connection axions dark energy theory |
発行日: | Aug-2023 |
出版者: | IOP Publishing |
誌名: | Journal of Cosmology and Astroparticle Physics |
巻: | 2023 |
号: | 08 |
論文番号: | JCAP08(2023)054 |
抄録: | We study theories of gravity including, in addition to the metric, several scalar fields in the gravitational sector. The particularity of this work is that we allow for direct couplings between these gravitating scalars and the matter sector, which can generally be different for the source and the probe of gravity, in addition to the universal interactions generated by the Jordan frame metric. The weak gravity regime of this theory, which would describe solar-system experiments, is studied using the parametrized post-Newtonian (PPN) formalism. We derive the expression of the ten parameters of this formalism. Among them, ζ₃ and ζ₄ are modified with respect to their values in the theories without direct couplings. This fact holds even after eliminating the direct couplings between the gravitating scalars and the energy density of the source, by redefinition of the Jordan frame. All other PPN parameters are insensitive to the direct couplings once in the correctly identified Jordan frame. When direct couplings are different for the source and the probe of gravity, they make non-relativistic probes deviate from the geodesics of the PPN metric in this frame, already at Newtonian order. Such couplings would thus be directly detectable and would have been excluded by experiments. This shows that, contrary to the claims in the recent literature, it is impossible to screen the presence of gravitating scalars relying only on a curved target space and direct couplings to matter. |
著作権等: | © 2023 The Author(s) Published by IOP Publishing Ltd on behalf of Sissa Medialab. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. |
URI: | http://hdl.handle.net/2433/286880 |
DOI(出版社版): | 10.1088/1475-7516/2023/08/054 |
出現コレクション: | 学術雑誌掲載論文等 |
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