Tidal Response Beyond the Background Geometry in Einstein-Euler-Heisenberg Black Holes

Abstract

We determine the quadrupolar logarithmic tidal response of electrically charged Einstein-Euler-Heisenberg black holes from the coupled static odd-parity gravitational and electromagnetic equations. Although the second electromagnetic invariant vanishes on the electric background, its quadratic interaction contributes to the axial fluctuation equations. At first order in the Euler-Heisenberg coupling $a$, a direct asymptotic recursion gives the canonical running matrix $C_{\mathrm{can}}^{\mathrm{EH}}=(9a{Q}^2/10)\left(\begin{array}{cc}0& -Q\\ -Q& M\end{array}\right)$, defined as the coefficients multiplying the canonical source vector in the $r^{-2}\log (r_0/r)$ term. The resulting local coefficients retain the full dependence on the subextremal ratio $\frac{Q}{M}$ at this perturbative order. The two quartic invariants partially cancel in both nonzero channels, while the action-normalized fields make gravitoelectromagnetic reciprocity explicit. The local extremal limit of the running matrix reproduces the corresponding two-invariant effective-field-theory result after convention conversion. Allowing independent quartic couplings further shows that identical electric background geometries can have different axial running matrices and yields algebraic inverse relations within the specified two-operator model. The calculation determines local logarithmic running within minimally coupled quartic electrodynamics; the finite horizon-matched response requires an additional global matching calculation.

14 pages, 2 figures