Methodology for changing two entangled states using quantum gates for a quantum circuit consisting of four Qubits

Abstract

This study introduces a systematic approach for controlling the output of a 4-qubit quantum circuit, initially prepared in the |0000⟩ state, to generate two entangled states. The procedure begins by enumerating all possible computational basis states of the circuit, followed by the creation of superposition states using the Hadamard gate. Entanglement between the qubits is then established through carefully applied CNOT gates. State manipulation is further implemented using the X-gate, allowing precise control of the resulting output. Each transformation converts the initial input into a four-qubit output containing two maximally entangled states. The proposed methodology emphasizes tailored gate selection based on the desired output and the configuration of the input qubits, providing a flexible framework for multi-qubit state engineering in quantum circuits.