Dynamics of a two-atom system with periodically driven interactions

• 1、School of Science, Beijing University of Posts and Telecommunications, Beijing 100876

Abstract：We study the dynamicis of a two-atom system with periodically driven interactions in a three-dimensional harmonic trap. By adjusting the scattering length between ultracold atoms, we theoretically simulate the dynamicis of a two-atom system over time. In this paper, we use a square wave driven scattering length and focus on the state of few-body excitation, to theoretically simulate the dynamicis of the average relative distance between atoms and the occupation of atoms in the eigenstate under different parameters. Through the Rabi oscillation analysis, we find that changing the driving frequency of the interaction and the duty cycle of the square wave affects the strength of the coupling between the ground state and excited state. When the driving frequency satisfies the difference of eigenenergies, the system is excited to a specific eigenstate, the relative distance between the atoms manifestes as a stable periodic oscillation, and when the two energy levels are strongly coupled, the driving frequency is equal to the average value of eigenenergies difference corresponding to the two scattering lengths. We analyze the evolution of the Tan\'s Contact of two-level oscillating systems, and the frequency component of the Contact oscillation period coincides with the frequency at which the relative distance between atoms oscillates. Finally, we use the generalization of the Rabi formula to obtain the driving frequency conditions satisfied by the resonance of the system.

Keywords： ultracold atoms periodically driven two-level system rabi oscillations