Quantum Fisher Information of a Two-Qubit System in Non-Markovian Environment

Considering a two-qubit system interacting with a common bosonic reservoir, this paper investigates the quantum Fisher information dynamics in the Markovian and non-Markovian environments, and focuses on the estimation of the phase and weight parameters in the non-Markovian environments. The results show that the quantum Fisher information for the estimation of the weight parameter does not change with time. For the estimation of the phase parameter, whether in the Markovian or non-Markovian environments, the time evolution of the quantum Fisher information can ultimately arrive at stabilization. In addition, the maximum value of the quantum Fisher information for the phase estimation in the non-Markovian environment is larger than that in the Markovian regime, which indicates that the estimation precision of the phase parameter in the non-Markovian regime is higher.