2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/211532There is a special relation between the spectrum and the {\it truncated} heat kernel of the Euclidean BTZ black hole with the Patterson-Selberg zeta function. Using an orbifold description of this relation we calculate the on-shell corrections of the gravitational quantum fluctuations.10 pages. To appear in the European Phys. J. CHigh Energy Physics - Theorytext