Spin dynamics in a chain with three-spin interactions in a transverse magnetic field

The quantum dynamics of a spin chain with three-spin interactions in the presence of a transverse magnetic field is investigated. We use both direct diagonalization and the method of recurrence relations to obtain the time-dependent correlation function and its corresponding frequency-dependent spectral density function. Although our calculations are done with chains up to 14 spins with periodic boundary conditions, the results are easily extended for infinite-size chains. We present the calculations for the behavior of these quantities as a function of the transverse magnetic field in the high-temperature limit.