We construct the Drinfeld twists (factorizing F -matrices) for the supersymmetric t-J model. Working in the basis provided by the F -matrix (i.e. the so-called F -basis), we obtain completely symmetric representations of the monodromy matrix and the pseudo-particle creation operators of the model. These enable us to resolve the hierarchy of the nested Bethe vectors for the gl(2|1) invariant t-J model.
I IntroductionThe algebraic Bethe ansatz or the quantum inverse scattering method (QISM) provides a powerful tool of solving eigenvalue problems such as diagonalizing integrable two-dimensional quantum spin chains. In this framework, the pseudo-particle creation and annihilation operators are constructed by the off-diagonal entries of the monodromy matrix. The Bethe vectors (eigenvectors) are obtained by acting the creation operators on the pseudo-vacuum state. However, the apparently simple action of creation operators is intricate on the level of the local operators by non-local effects arising from polarization clouds or compensating exchange terms. This makes the exact and explicit computation of correlation functions difficult (if not impossible).Recently, Maillet and Sanchez de Santos [1] showed how monodromy matrices of the inhomogeneous XXX and XXZ spin chains can be simplified by using the factorizing Drinfeld twists. This leads to the natural F -basis for the analysis of these models. In this basis, the pseudo-particle creation and annihilation operators take completely symmetric forms and contain no compensating exchange terms on the level of the local operators (i.e. polarization free). As a result, the Bethe vectors of the models are simplified dramatically and can be written down explicitly.The results of [1] were generalized to certain other systems. In [3], the Drinfeld twists associated with any finite-dimensional irreducible representations of the Yangian Y [gl(2)] were investigated. In [4], the form factors for local spin operators of the spin-1/2 XXZ model were computed and in [5], the spontaneous magnetization of the XXZ chain on the finite lattice was represented. In [2], Albert et al constructed the F -matrix of the gl(m) rational Heisenberg model and obtained a polarization free representation of the creation operators. Using these results, they resolved the hierarchy of the nested