Scalar field coupled to boundary in non-metricity: a new avenue towards dark energy
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arXiv
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| Autori principali: | , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2026
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| _version_ | 1866914328391712768 |
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| author | Murtaza, Ghulam De, Avik Loo, Tee-How Paliathanasis, Andronikos |
| author_facet | Murtaza, Ghulam De, Avik Loo, Tee-How Paliathanasis, Andronikos |
| contents | While conformal transformations in metric scalar-tensor theories recover General Relativity, this feature is notably absent in standard non-metricity-based theories. We demonstrate that by introducing the boundary term C, a non-metricity scalar-tensor theory can recover Symmetric Teleparallel Equivalent of General Relativity (STEGR) in the Einstein frame. Motivated by this, we propose a novel gravity model where a scalar field couples nonminimally to both the non-metricity scalar Q and the boundary term C. We focus in the cosmological scenario where we present the covariant formulation and a unified autonomous system framework that treats generic affine-connection choices, including coincident and non-coincident gauges, on an equal footing. Our dynamical analysis across three connection branches reveals standard thermal histories and stable de Sitter attractors. These results show that boundary-term couplings provide a well-posed, geometrically flexible route to addressing late-time cosmic acceleration. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2602_12981 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Scalar field coupled to boundary in non-metricity: a new avenue towards dark energy Murtaza, Ghulam De, Avik Loo, Tee-How Paliathanasis, Andronikos General Relativity and Quantum Cosmology While conformal transformations in metric scalar-tensor theories recover General Relativity, this feature is notably absent in standard non-metricity-based theories. We demonstrate that by introducing the boundary term C, a non-metricity scalar-tensor theory can recover Symmetric Teleparallel Equivalent of General Relativity (STEGR) in the Einstein frame. Motivated by this, we propose a novel gravity model where a scalar field couples nonminimally to both the non-metricity scalar Q and the boundary term C. We focus in the cosmological scenario where we present the covariant formulation and a unified autonomous system framework that treats generic affine-connection choices, including coincident and non-coincident gauges, on an equal footing. Our dynamical analysis across three connection branches reveals standard thermal histories and stable de Sitter attractors. These results show that boundary-term couplings provide a well-posed, geometrically flexible route to addressing late-time cosmic acceleration. |
| title | Scalar field coupled to boundary in non-metricity: a new avenue towards dark energy |
| topic | General Relativity and Quantum Cosmology |
| url | https://arxiv.org/abs/2602.12981 |