25791 2501.05036 10.1007/JHEP03(2025)135 135 135 Brane cosmology from AdS/BCFT Regular Article - Theoretical Physics 1 45 2025 3 18 2025 1 23 2025 2 7 2025 3 18 The Author(s) 2025 Open Access. This article is distributed under the terms of the Creative Commons Attribution License ( CC-BY 4.0 ), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited. 13130 2025 2025 3 3 Kosei Fujiki kosei.fujiki@yukawa.kyoto-u.ac.jp Hiroki Kanda hiroki.kanda@yukawa.kyoto-u.ac.jp Michitaka Kohara michitaka.kohara@yukawa.kyoto-u.ac.jp Tadashi Takayanagi takayana@yukawa.kyoto-u.ac.jp https://ror.org/02kpeqv85 grid.258799.8 0000 0004 0372 2033 Center for Gravitational Physics and Quantum Information Yukawa Institute for Theoretical Physics, Kyoto University Kitashirakawa Oiwakecho, Sakyo-ku Kyoto 606-8502 Japan Inamori Research Institute for Science 620 Suiginya-cho, Shimogyo-ku Kyoto 600-8411 Japan Abstract In this paper, we study the time-dependent dynamics of an end-of-the-world (EOW) brane in AdS with a scalar field localized on the brane. We mainly studied several aspects of holography and cosmology. Standard requirements in the AdS d+1/CFT d lead to a constraint on the conformal dimension in the dS d /CFT d−1. We also prove a time-like analog of g-theorem using the null energy condition in the context of AdS3/BCFT2. In the cosmological interpretation, we rewrite the equation of motion of the brane as a Friedman-like equation, which enables us to consider its dynamics in analogy with the ordinal cosmology. And then we classify all possible solutions of the brane when the potential takes a constant value. We find that our brane cosmology model can describe a process of creating a universe via a big-bang. Additionally, we show that when the brane is close to a hyperplane, its effective action is given by a Liouville gravity with a scalar field matter. Finally, we also obtain brane solutions with boost symmetry, which are obtained by analytical continuation of Euclidean branes with a torus topology. Keywords AdS-CFT Correspondence Cosmological models ArXiv ePrint: 2501.05036