Generation of Entanglement in Qutrit Spin Coherent States by Nonlinear Hamiltonian

We study entanglement in coherent spin states and several superpositions of multi-qutrit coherent states evolved under the one-axis counter-twisting Hamiltonian in the presence and absence of a magnetic field. Considering a non-entangled multi-qutrit spin coherent state as an initial one, it is found that the entanglement is instigated with an oscillatory behavior in time; however, its average is a decreasing function of the magnetic field. Also, we observe that under this Hamiltonian, the two-qutrit superposed state retains its maximum entanglement with no change, while, the negativity for the three-qutrit superposed state oscillates in time and its average increases in the presence of the magnetic field.