In general, the coefficients formula_9 and formula_10 are complex numbers. In this scenario, one qubit of information is said to be encoded into the quantum memory. The state formula_5 is not itself a probability vector but can be connected with a probability vector via a measurement operation. If the quantum memory is measured to determine whether the state is formula_6 or formula_7 (this is known as a computational basis measurement), the zero state would be observed with probability formula_14 and the one state with probability formula_15. The numbers formula_9 and formula_10 are called quantum amplitudes.