Please, help me with this problem! Two distinguishable particles of spin 1/2 interact with Hamiltonian H=A*S1,z*S2,x with A a positive constant. S1,z and S2,x are the operators related to the z-component of the spin of the first particle and to the x-component of the spin of the second particle, respectively. If at t=0 the system is in its simultaneous eigenket of S1,z for the eigenvalue h/4pi (ħ/2) and of S2,x for the eigenvalue h/4pi (ħ/2), FIND THE STATE OF THE SYSTEM AT THE TIME t Attempt of solution: Firstly, one should use the formulas for temporal evolution. Please, help me!