Quantum Computing, Quantum Fourier Transform, Mathematics.
Fourier basis (Figure 1.1b): Figure 1.1b Fourier computational basis for four-qubit system (Source: Qiskit documentation) You basically rotate all the qubits about the z-axis on the xy plane. QFT Proof A quantum Fourier state is represented with a tilde (~). A qubit with a tilde represents a qubit