Solid‐State Qubit as an On‐Chip Controller for Non‐Classical Field States

A basic element of a quantum network based on two single‐mode waveguides is proposed with different frequencies connected by a solid‐state qubit. Using a simple example of a possible superconducting implementation, the usefulness of the simplifications used in the general theoretical consideration has been justified. The non‐classical field in a single‐mode with a frequency of ω1$\omega _1$ is fed to the input of a qubit controller and transformed into a non‐classical field in an output single‐mode with a frequency of ω2$\omega _2$. The interface can establish a quantum connection between solid‐state and photonic flying qubits with adjustable pulse shapes and carrier frequencies. This allows quantum information to be transferred to other superconducting or atomic‐based quantum registers or chips. The peculiarities of the wave‐qubit interactions are described, showing how they help to control the quantum state of the non‐classical field. On this basis, the operating principles of solid‐state and flying qubits for the future quantum information platforms are considered. Current research in quantum matter is strongly focused on quantum communication and the quantum internet. The manuscript discusses a fundamental element of a quantum network consisting of two single‐mode resonators of different frequencies connected by a solid‐state qubit. The non‐classical field in a single‐mode resonator operating at frequency ω1$\omega _1$ is directed to the input of a qubit controller and subsequently converted to a non‐classical field in an output single‐mode resonator operating at frequency ω2$\omega _2$. This interface provides a quantum connection between solid‐state and photonic flying qubits, offering tunable pulse shapes and carrier frequencies.