Protecting Quantum Coherence and Quantum Fisher Information in Ohmic Reservoir

Quantum coherence(QC) and quantum Fisher information(QFI) are investigated for the atom in Jaynes-Cummings model coupling with the Ohmic reservoir at zero temperature when the total excitation number N = 1. We discuss in detail the influence of the atom-cavity coupling and the reservoir parameters on QC and QFI. The results show that QC and QFI of the atom can be effectively controlled by the atom-cavity coupling and the reservoir parameters. Namely, the larger atom-cavity coupling and the appropriate reservoir parameters can effectively protect QC and QFI. Moreover, QC can improve QFI. Last, we provide a physical explanation using the decoherence rate.