Extended Order Parameter and Conjugate Field for the Dynamic Phase   Transition in a Ginzburg-Landau Mean-Field Model in an Oscillating Field
  We present numerical evidence for an extended order parameter and conjugate field for the dynamic phase transition in a Ginzburg-Landau mean-field model driven by an oscillating field. The order parameter, previously taken to be the time-averaged magnetization, comprises the deviations of the Fourier components of the magnetization from their values at the critical period. The conjugate field, previously taken to be the time-averaged magnetic field, comprises the even Fourier components of the field. The scaling exponents beta and delta associated with the extended order parameter and conjugate field are shown numerically to be consistent with their values in the equilibrium mean-field model. 
Daniel T. Robb and Aaron Ostrander
cond-mat.stat-mech