QubittaQuantum SuperpositionMug

Qubitta is one qubit, and she holds two amplitudes at once.

The first line is her state: two basis states, written |0⟩ and |1⟩, combined with complex amplitudes α and β. Measure her in that basis and you get 0 with probability |α|² or 1 with probability |β|². The probabilities add to one, the second line. After the measurement the superposition is gone and she is in whichever state you found.

BOTH, UNTIL YOU LOOK. is the popular shorthand, and it needs a footnote. A superposition is not a hidden choice made in advance, and it is not literally two values at once. It is one definite state. A qubit pointing one way in one basis can be an equal superposition in another: measure in a different basis and you need not get 0 or 1 at all.

The amplitudes also carry a phase that probabilities throw away. Flip the sign of β and the odds of 0 and 1 do not change, but measured in another basis the two states can be told apart perfectly. Quantum computers work by steering those phases so that wrong answers cancel and right answers reinforce.

What a superposition means physically is still argued between interpretations. The mathematics, and the predictions, are not. Qubitta is not undecided. She is exactly what her amplitudes say.