Real and damped modes for an interacting fermion–antifermion pair: exciton in monolayer medium Abdullah Guvendi, Semra Gurtas Dogan and Uzeyir Yazıcı Eur. Phys. J. Plus, 139 4 (2024) 337 Published online: 16 April 2024 DOI: 10.1140/epjp/s13360-024-05101-6