Dynamic Properties of Spin-1/2 XX Chain with Three-Site Interactions of (XZY - YZX)-Type

We consider the spin-1/2 isotropic XY chain in a transverse field with three-site interactions of (XZY - YZX)-type, which can be transformed into a system of noninteracting spinless fermions. We study dynamic properties of the spin model. In particular, we calculate the dynamic structure factors which are governed by a two-fermion excitation continuum. We demonstrate how the three-site interactions manifest themselves in the dynamic properties of the quantum spin chain.