Transition rates via Bethe ansatz for the spin-1/2 Heisenberg chain

We use the exact determinantal representation derived by Kitanine, Maillet, and Terras for matrix elements of local spin operators beween Bethe wave functions of he one-dimensional s = 1/2 Heisenberg model to calculate and numerically evaluate transition rates pertaining to dynamic spin structure factors. For real solutions z(1),..., z(r) of the Bethe ansatz equations, the size of he determinants is of order r x r. We present applications to the zero-temperature spin fluctuations parallel and perpendicular to an external magnetic field.