Dynamics of two magnons coupled to an open microwave cavity: local quantum Fisher- and local skew-information coherence

This paper investigates the generation and robustness of two-magnon quantum correlation and coherence in noisy channels. The system consists of two-sublattice magnons interacting with photons inside a cavity, which leads to magnon–magnon and photon–magnon interactions. The influence of cavity dissipation and spontaneous emission on two-magnon dynamics is analyzed using several correlation and coherence measures (specifically, local quantum uncertainty, local quantum Fisher information, and concurrence) for different magnon–magnon and photon–magnon couplings. In the absence of the cavity dissipation and spontaneous emission, the results show the ability of the photon–magnon and magnon–magnon interactions (with a pure photon–magnon state as the initial state) to generate a maximal magnon–magnon mixedness and quantum correlation. The local quantum uncertainty and local quantum Fisher information exhibit sudden changes’ phenomenon. In case of an initial maximal correlated two-magnon state, the local quantum Fisher information and the concurrence are not fragile in comparison with the local uncertainity by variation of photon–magnon interactions. The two-magnon correlations decrease as the spontaneous emission and the cavity dissipation increase, whereas the coherence of the two-magnon local quantum Fisher and local skew information is sustained at their maxima.