Periodic Driving at High Frequencies of an Impurity in the Isotropic XY   Chain
  We study the isotropic XY chain with a transverse magnetic field acting on a single site and analyse the long time behaviour of the time-dependent state of the system when a periodic perturbation drives the impurity. We find that for high frequencies the state approaches a periodic orbit synchronised with the forcing and provide the explicit rate of convergence to the asymptotics. 
Livia Corsi and Giuseppe Genovese
math-ph cond-mat.stat-mech math.MP