Quantum systems whose dynamics depends on one or more control functions are called quantum control systems. This chapter describes elements of the theory of field-particle interaction. It starts with the classical theory of electrodynamics and shows how to obtain the quantum mechanical description through a process called canonical quantization. The chapter presents physical examples of quantum control systems of interest in applications and highlights the fact that such systems have a common mathematical structure. In the external system, the motion of the charges, are fixed and independent of the field. Canonical quantization is the process which associates quantities in classical mechanics with operators in quantum mechanics.
Abstract This chapter is devoted to discussing relevant dynamical and superfluid phenomena exhibited by interacting Fermi gases at low temperatures, with special focus on the strongly interacting Fermi gas at unitarity. The chapter discusses the predictions of hydrodynamic theory concerning the propagation of sound, the collective oscillations and the expansion of the gas after release of the trap. The Landau criterion for superfluidity and the behaviour of the dynamic structure factor are discussed. It also provides some considerations on the radiofrequency transitions as a method to observe pair-breaking transitions and to measure the pairing gap. The chapter discusses the behaviour of two-fluid hydrodynamics and the propagation of second sound as a tool to measure the superfluid density of interacting Fermi gases. It finally provides a brief summary of the rotational properties of the superfluid Fermi gas, like the quenching of the moment of inertia and the occurrence of quantized vortices.