What is superposition?
A qubit state that is a blend of 0 and 1, with an amplitude for each.
A qubit in superposition is not secretly 0 or 1 with the answer hidden. It holds both amplitudes at once, and those amplitudes can add up or cancel with others, which is what interference uses.
A superposition doesn’t give you many answers to read. Measurement returns one result and the blend is gone.
In the lessonsSee it in a simulation
Related
- QubitThe basic unit of a quantum computer: it can be 0, 1, or a blend of both until it is measured.
- AmplitudeThe number a qubit holds for each possible result. Squaring it gives the chance of that result.
- MeasurementReading a qubit. It returns 0 or 1 at random, with chances set by the squared amplitudes, and ends the blend.
- InterferenceAmplitudes adding up or cancelling when they combine. Quantum algorithms use it to make wrong answers unlikely.