Entanglement Evolution of Two-Coupled Spins in a Time-Dependent Rotating Magnetic Field

<正> We study the dynamics evolution of a two-qubit Heisenberg XXX spin chain under a time-dependentrotating magnetic field.Based on the algebraic structure of the non-autonomous system,the exact solution of theSchrdinger equation is obtained by using the method of algebraic dynamics.Based on the time-dependent analyticalsolution,we further study the entanglement evolution between the two coupled spins for different initial states,and findthat the entanglement is determined by the coefficients of the initial state and the coupling constant J of the system.