Quasitopological Gravity with Matter: Modified Double-Copy Approach
Abstract
We extend the recently proposed modified double-copy formalism to quasitopological gravity (QTG) coupled to matter. For spherically symmetric configurations, the QTG field equations in D−dimensional curved spacetime with a broad class of matter sources are mapped to equations for an auxiliary nonlinear gauge field in a flat (D+1)-dimensional spacetime. The nonlinear electrodynamics governing this auxiliary field is determined entirely by the generating function h(p) that specifies the QTG model, while the corresponding current is determined by the matter stress-energy tensor. Restricting the auxiliary solution to a D-dimensional hyperplane and applying the modified double-copy prescription yields the Kerr--Schild metric solving the QTG equations. We show that Maxwell and nonlinear electrodynamics, as well as a broad class of spherically symmetric Yang--Mills fields, provide physical matter sources compatible with this construction. In the absence of null-matter fluxes, the corresponding solutions possess an additional Killing vector. This means that they satisfy a generalized Birkhoff theorem, whereas null charged currents naturally generate Vaidya-type solutions. In the Einstein limit, h(p)=p, the auxiliary nonlinear electrodynamics reduces to Maxwell theory.
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BibTeX
@misc{frolov2026quasitopological,
title = {{Quasitopological Gravity with Matter: Modified Double-Copy Approach}},
author = {Valeri P. Frolov},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2608.12596},
eprint = {2608.12596},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.12596},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Quasitopological Gravity with Matter: Modified Double-Copy Approach
AU - Valeri P. Frolov
PY - 2026
DA - 2026/10/07
PB - arXiv
DO - 10.48550/arxiv.2608.12596
UR - https://arxiv.org/abs/2608.12596
AB - We extend the recently proposed modified double-copy formalism to quasitopological gravity (QTG) coupled to matter. For spherically symmetric configurations, the QTG field equations in D−dimensional curved spacetime with a broad class of matter sources are mapped to equations for an auxiliary nonlinear gauge field in a flat (D+1)-dimensional spacetime. The nonlinear electrodynamics governing this auxiliary field is determined entirely by the generating function h(p) that specifies the QTG model, while the corresponding current is determined by the matter stress-energy tensor. Restricting the auxiliary solution to a D-dimensional hyperplane and applying the modified double-copy prescription yields the Kerr--Schild metric solving the QTG equations. We show that Maxwell and nonlinear electrodynamics, as well as a broad class of spherically symmetric Yang--Mills fields, provide physical matter sources compatible with this construction. In the absence of null-matter fluxes, the corresponding solutions possess an additional Killing vector. This means that they satisfy a generalized Birkhoff theorem, whereas null charged currents naturally generate Vaidya-type solutions. In the Einstein limit, h(p)=p, the auxiliary nonlinear electrodynamics reduces to Maxwell theory.
ER -