Quantum Computing, Quantum Information, Quantum, Quantum Fourier Transform, Quantum Entanglement.
Invariant, and it is important in many applications of QFT in quantum algorithms. A periodic n-qubit state, let us call it |ψ(r,l)⟩, is a state that shows a periodic behavior in its writing. It can be defined by its period r and its shift l, and expressed as follows: The shift indicates the first