Level 2, Tinkerer

Gate

H splits the state certain to read 0 into two equal amplitudes, X moves the state certain to read 0 onto the state certain to read 1, and Z flips the sign on one bar of the |+⟩ state. Between them, a single qubit can be split, swapped, and given a new sign.

A gate is an operation that rewrites the amplitudes of one or more qubits according to a fixed rule. On this shelf the first three gates act on a single qubit, and between them they can split a state, swap the two amplitudes, and flip a sign.

Keith collects nicknames for gates the way other people collect beermats from pubs they half remember. The entries here use the letters, and the nicknames are confined to the second paragraph where a wrong one can be corrected in the same breath.

Used in

All the words