On positronium states in $\mathrm{QE}{\mathrm{D}}_3$

Chang-Yong Liu, You-Wei Li, Su-Zhi Wu

In this note, we present a new method to investigate the positronium states in $\mathrm{QE}{\mathrm{D}}_3$. According to the $\mathrm{K}\ddot{\mathrm{a}}\mathrm{ll}\acute{\mathrm{e}}\mathrm{n}-\mathrm{Lehmann}$ spectral representation, the en…