Comments on lump solutions in SFT | The European Physical...
The last term vanishes since it is BRST exact and the first term in the second line gives $$\begin{aligned} E[\psi _{ES}]= & {} \frac{1}{6} \int _0^\infty \mathrm{d}t_1\mathrm{d}t_2 \, e^{-t_1-t_2}\langle c\, e^{-t_1 K}\,c \partial c \,e^{-t_2K}\...