Drinfeld twist and symmetric Bethe vectors of the open XYZ chain with   non-diagonal boundary terms
  With the help of the Drinfeld twist or factorizing F-matrix for the eight-vertex solid-on-solid (SOS) model, we find that in the F-basis provided by the twist the two sets of pseudo-particle creation operators simultaneously take completely symmetric and polarization free form. This allows us to obtain the explicit and completely symmetric expressions of the two sets of Bethe states of the model. 
Wen-Li Yang, Xi Chen, Jun Feng, Kun Hao, Ke Wu, Zhan-Ying Yang and   Yao-Zhong Zhang
hep-th math-ph math.MP