Effect of quantum subsystem–subsystem coupling in hybrid systems

Abstract

In this paper, we study the effect of quantum subsystem–subsystem coupling on the magnetic-like field that the classical subsystem feels in a quantum–classical hybrid system. The hybrid system is composed of a classical magnetic particle and two coupled spins. We show that (i) when the spin–spin interaction is equal to the magnetic–spin interaction, the magnetic-like field changes sharply. This observation becomes more clear when the distance between the two subsystems is much longer than the magnetic particle's rotating radius. (ii) When the spin–spin interaction is larger than the coupling between the quantum classical systems, the effect that the quantum subsystem acts on in the classical part approaches zero. Some useful applications are also discussed.