| Texto completo | |
| Autor(es): |
Bittar, Pedro
;
Fichet, Sylvain
;
de Souza, Lucas
Número total de Autores: 3
|
| Tipo de documento: | Artigo Científico |
| Fonte: | PHYSICAL REVIEW D; v. 112, n. 4, p. 27-pg., 2025-08-21. |
| Resumo | |
We compute the four-photon (F4) operators generated by loops of charged particles of spin 0, 12, 1 in the presence of gravity and in any spacetime dimension d. To this end, we expand the one-loop effective action via the heat kernel coefficients, which capture both the gravity-induced renormalization of the F4 operators and the low-energy Einstein-Maxwell effective field theory (EFT) produced by massive charged particles. We set positivity bounds on the F4 operators using standard arguments from extremal black holes (for d >= 4) and from infrared (IR) consistency of four-photon scattering (for d >= 3). We find that both approaches yield nearly equivalent results, even though in the amplitudes we discard the graviton t-channel pole and use the vanishing of the Gauss-Bonnet term at quadratic order for any d. The positivity bounds constrain the charge-to-mass ratio of the heavy particles. If the Planckian F4 operators are sufficiently small or negative, such bounds produce a version of the d-dimensional weak gravity conjecture (WGC) in most, but not all, dimensions. In the special case of d = 6, the gravity-induced beta functions of F4 operators from charged particles of any spin are positive, leading to WGC-like bounds with a logarithmic enhancement. In d = 9, 10, the WGC fails to guarantee extremal black hole decay in the infrared EFT, thereby requiring the existence of sufficiently large Planckian F4 operators. (AU) | |
| Processo FAPESP: | 23/11293-0 - Anomalias e fronteiras |
| Beneficiário: | Lucas de Souza |
| Modalidade de apoio: | Bolsas no Brasil - Doutorado Direto |
| Processo FAPESP: | 21/10128-0 - Teoria quântica de campos sob a influência de condições externas |
| Beneficiário: | Dmitry Vasilevich |
| Modalidade de apoio: | Auxílio à Pesquisa - Temático |