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arXiv · 2603.19819

Casimir-Induced Quintessence in Dark Dimension

Tomoki Katayama·Hiroki Matsui·Yuri Michinobu·Fumiya Okamatsu·Yutaka Sakamura·Takahiro Terada
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Abstract

We investigate a concrete realization of the Dark Dimension scenario, where a single large extra dimension is set at sub-millimeter scales. In this framework, the Casimir energy of bulk fields accounts for the observed dark energy. Working in a 5-dimensional setup with the Standard Model confined to a 4-dimensional brane, we derive the effective action for the radion. We demonstrate that a minimal model comprising only gravity and three right-handed bulk neutrinos typically yields a negative radion potential. To realize a positive vacuum energy, we consider some extensions with additional bulk degrees of freedom. These extensions generate a sufficiently flat positive potential that allows the radion to behave as a quintessence field, evolving slowly at the sub-eV scale. Finally, we analyze the evolution of the dark-energy equation-of-state parameter and show that our model is consistent with recent DESI BAO measurements, including the distance ratios $D_H/r_d$ and $D_M/r_d$.

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Tomoki Katayama, Hiroki Matsui, Yuri Michinobu, Fumiya Okamatsu, Yutaka Sakamura, Takahiro Terada. 2026-03-20. Casimir-Induced Quintessence in Dark Dimension. https://arxiv.org/abs/2603.19819

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