Allan Alonzo-Artiles | Searcharxiv

arXiv2026

Classical Hamiltonian of Reissner-Nordström black holes at second post-Minkowskian order from scattering amplitudes

We employ scattering amplitudes in Einstein-Maxwell theory to compute the classical Hamiltonian of a binary system of two charged, non-spinning compact objects. The effective Hamiltonian is valid to all orders in velocity and up to second post-Minkowskian order (2PM), i.e. $\mathcal{O}(G^2)$. The classical interaction potential is extracted via matching the four-point tree and one-loop amplitudes to those of a suitably chosen classical effective field theory. We derive the 2PM scattering angle from the Hamiltonian and find complete agreement with nown results. Using also the third order result for the scattering angle computed by Wilson-Gerow, we expand the scattering angle at second post-Newtonian order (2PN). Additionally, we provide expressions for the binding energy and periastron advance at 2PN order via the boundary-to-bound dictionary introduced by Kälin and Porto and find agreement with previous findings.

hep-th↗

arXiv2021

The Higgs-Graviton Couplings: from Amplitudes to the Action

In this paper we study the coupling of scalar (Higgs) particles ($ϕ$) with gravitons ($h$) and their possible effects. The general form of the 3-point interaction $ϕ(p) h(1)h(2)$ can be derived using the scaling behavior of the spinor variables under the little group; the resulting vertices exhibit such simplicity, that some simplifications should be hidden in the expressions obtained from the extended scalar action. To investigate this, we study an extended Einstein-Hilbert action that besides the minimal coupling, it also includes terms of the form $ϕR^2$, $ϕR^{μν} R_{μν}$ and $ϕR^{μνρσ} R_{μνρσ}$, as well as the term $ε_{μναβ} ϕ_5 R^{μν}_{ρσ} R^{αβρσ}$ for the case of a pseudo-scalar ($ϕ_5$). The resulting vertices satisfy KLT-type relations, i.e., they can be written as the square of the coupling of the Higgs with gluons. We find that the amplitude for the Higgs decay into a pair of gravitons (on-shell) only receives a contribution coming from the square of the Riemann tensor. Similar results are obtained for the 3-body decay $ϕ\to h h^* (\to XX)$, with an off-shell graviton ($h^*$) that goes into the final state $XX$. One could expect that these quadratic terms can produce new loop effects, however we find that the new contribution from this non-minimal coupling to the graviton self-energy, also vanishes for on-shell gravitons.

hep-th↗