Quantum coupling between radio modes in a single-atom maser with two resonators

In this work, we investigate the effect of quantum coupling between radio fields in a single-atom maser with two spatially separated resonators. Each atom in a beam, depending on its state, can emit one photon into the first resonator and absorb another from the second, thereby entangling the quantum states of two independent modes. Resulting from entanglement, we obtain a coherence between states of two-mode field with the same total number of photons in the both modes. To study the arising coupling, an analytical solution of the stationary master equation is found under conditions of a trapped field state and the dependence of the von Neumann entanglement entropy on the quality factor of the resonators. Numerical analysis reveals that the best conditions for the appearance of quantum coupling are the low quality factor of the first resonator and the high quality factor of the second one.