Smooth optimal control with Floquet theory

This paper describes an approach to construct temporally shaped control pulses that drive a quantum system toward desired properties. A parametrization in terms of periodic functions with predefined frequencies permits us to realize a smooth, typically simple shape of the pulses; their optimization can be performed based on a variational analysis with Floquet theory. As we show with selected specific examples, this approach permits us to control the dynamics of interacting spins, such that gate operations and entanglement dynamics can be implemented with very high accuracy.