One-loop off-shell amplitudes from classical equations of motion

A type of unifying relation in (A)dS spacetime

“…In principle, there are still several unifying relations for which we do not give rigorous proof, which may be discussed in future work. It is necessary to mention that the correlation functions at the loop level can also be constructed by BG currents [7]. And we are looking forward to deriving the relations among 1-loop level correlation functions [41,42] in future work.…”

“…As a semi-on-shell method, Berends-Giele (BG) currents [5] are popular because of their recursive character. In recent years, many techniques based on BG currents have been developed [6][7][8][9][10][11][12][13][14][15][16][17]. However, the research of BG currents in (A)dS is still very scarce.…”