  In this work, we study the time evolution of a coherent spin state under the
action of a non-hermitian hamiltonian. The hamiltonian is modeled by a one-axis
twisting term plus a Lipkin-type interaction. We show that when the Lipkin
interaction is switched on, depending on the relative values of the coupling
constants, the initial state evolves into a steady squeezed state which
minimizes the Uncertainty Relations, Intelligent Spin State. We apply this
result to look for the generation of an steady intelligent spin state from an
ensemble of nitrogen vacancy colour centers in diamond coupled to a mechanical
resonator.
