Optimal quantum parameter estimation of two-qutrit Heisenberg XY chain under decoherence

Adopting the Milburn decoherence model, we investigate the performance of quantum Fisher information of the two-qutrit isotropic Heisenberg XY chain under decoherence. We find that the quantum Fisher information with respect to the decoherence rate and the magnetic field decreases exponentially in the long-time limit, which significantly reduces the precision of optimal quantum estimation. We also show that with the increase of the decoherence rate or the magnetic field, the QFIs go down considerably. Furthermore, we find that the precision of optimal quantum estimation can be enhanced by the entanglement in the input state.