Quantum
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Complex Numbers

Every complex number has two pieces: a magnitude (length) and a phase (angle). Drag the sliders below to see how the polar form (magnitude and phase) relates to the Cartesian form (real and imaginary parts).

This widget lives at the heart of the qubit story. In quantum computing, amplitudes are complex numbers — and their phases are what make quantum interference possible. See the full story in Lesson 1: Bits, chance, and complex numbers .