2021-09-27T04:52:42Zhttps://nagoya.repo.nii.ac.jp/oaioai:nagoya.repo.nii.ac.jp:000233832021-03-01T14:36:32ZSome solutions for one of the cosmological constant problemsNojiri, Shin’ichiElectronic version of an article published as [Modern Physics Letters A. v.31, n.37, 2016, p.1650213] [http://dx.doi.org/10.1142/S0217732316502138] © [copyright World Scientific Publishing Company] [http://www.worldscientific.com/worldscinet/mpla]Vacuum energycosmological constantgravityWe propose several covariant models which may solve one of the problems in the cosmological constant. One of the models can be regarded as an extension of sequestering model. Other models could be regarded as extensions of the covariant formulation of the unimodular gravity. The contributions to the vacuum energy from the quantum corrections from the matters are absorbed into a redefinition of a scalar field and the quantum corrections become irrelevant to the dynamics. In a class of the extended unimodular gravity models, we also consider models which are regarded as topological field theories. The models can be extended and not only the vacuum energy but also any quantum corrections to the gravitational action could become irrelevant for the dynamics. We find, however, that the BRS symmetry in the topological field theories is broken spontaneously and therefore, the models might not be consistent.World Scientific2016-12-07engjournal articlehttp://hdl.handle.net/2237/25578https://nagoya.repo.nii.ac.jp/records/233830217-7323Modern Physics Letters A313716502131650213https://nagoya.repo.nii.ac.jp/record/23383/files/SSCCRR.pdfapplication/pdf94.8 kB2017-12-07