Quantum circuit and method for implementing heterogeneously encoded logical bell state

A method of operating a quantum circuit configured to a logical Bell state heterogeneously encoded by different quantum error correction codes, the operation method comprising:

• performing a Hadamard conversion on cat states;
• performing CNOT operations on a result of the Hadamard conversion and first and second logical qubits encoded by first and second quantum error correction codes, respectively;
• measuring results of the CNOT operations;
• and
• performing a conversion on a bit of the second logical qubit on a basis of the measured results.

A quantum circuit comprising:

• first to third quantum circuits, each of which comprises:
• a Hadamard gating circuit configured to perform Hadamard conversions on cat states;
• a CNOT gating circuit configured to perform CNOT operations on first and second logical qubits encoded by first and second quantum error correction codes, respectively, and conversion results of the Hadamard gating circuit;
• and
• a measuring circuit configured to measure calculation results of the CNOT gating circuit;
• a selection circuit configured to receive a measured result of the measuring circuit of each of the quantum circuits and select a target quantum state;
• and
• a logical bit converter configured to convert a bit of the second logical qubit output from the third quantum circuit on a basis of the selection result of the selection circuit.