Quantum circuit for shifting phase of target qubit based on control qubit

Abstract

The inventive concept relates to a quantum circuit that shifts the phase of a target qubit by π/2based on a control qubit. The quantum circuit may include a first auxiliary circuit, a rotation gate, and a second auxiliary circuit. The first auxiliary circuit converts the first qubit state into the second qubit state according to the entanglement of a control qubit, a target qubit, and an ancillary qubit having a |0> state. The rotation gate shifts the phase for some basis states of the second qubit state by π/2, and converts the second qubit state to the third qubit state. The second auxiliary circuit converts the third qubit state to the fourth qubit state such that the phase of the target qubit is shifted by π/2.