Distant entanglement generation and controllable information transfer via magnon–waveguide systems

The generation of entanglement and information distribution among macroscopic systems which are spatially separated are of paramount importance in the realm of quantum networks and quantum communication. In this paper, we propose a scheme that enables the preparation of long-distance entanglement between two magnons and controllable information transfer from a giant atom to either magnon, where the two magnons can be positioned symmetrically or asymmetrically in relation to a giant atom, and all of the magnons and the atom are coupled to a microwave cavity-array waveguide. By considering significant frequency detuning, we can virtually excite photons and establish an indirect interaction between the giant atom and the two magnons. Through the modulation of atom–waveguide coupling rates, we can not only evenly transfer atomic excitation to both magnons, thereby generating maximally entangled states, but also selectively transmit the atomic state to a single magnon. It is our hope that our proposed scheme will prove valuable in the field of quantum communications.