Quasitopological gravity and double-copy formalism

Abstract: We propose a new approach to the quasitopological theory of gravity based on a modified classical double--copy construction. Focusing on static, spherically symmetric configurations, we show that all vacuum solutions of $D$--dimensional quasitopological gravity can be obtained from an auxiliary non--linear electrodynamics defined in a flat $(D+1)$--dimensional spacetime. The gravitational field equations reduce to an algebraic relation between a primary curvature invariant and the electric field strength, while the remaining dynamics is governed by a Gauss--law constraint for a point--like charge in the auxiliary space. This correspondence provides a transparent interpretation of higher--curvature gravitational interactions in terms of non--linear gauge dynamics and explains the absence of higher--derivative terms in the reduced equations. As illustrative examples, we apply the formalism to Born--Infeld and Hayward--type models, obtaining higher--dimensional regular black--hole solutions with a de~Sitter--like core. Our results extend the scope of the double--copy paradigm beyond Einstein gravity and suggest a unifying framework for a broad class of higher--curvature theories.