Exact Thermodynamics and Two-Horizon Relations of Four Rotating Einstein-Maxwell-Maxwell-Dilaton Embeddings

Abstract

We establish complete outer-horizon thermodynamics for four exact rotating embeddings of Kerr--Newman and Kaluza--Klein seeds in four-dimensional, asymptotically flat Einstein--Maxwell--Maxwell--dilaton theory without a scalar potential. Constant-coefficient field maps determine the allowed couplings and charge variations. We obtain single-valued mass functions and verify the first law, Smarr relation, and scalar-shift identity on the stated regular branches and finite-area extremal boundaries, including magnetic patch contributions where required. For two distinct regular horizons with positive finite areas, the horizon combinations $2T_{\pm }{S}_{\pm }$ and $S_{\pm }{\Omega }_{\pm }/\pi$ satisfy a common quadratic relation with the long-range-force parameter determined by the asymptotic mass, electromagnetic charges, and scalar charge.

arXiv comment27 pages