# Quantum Probability as Area on Bloch Sphere

Quantum Probability as Area on Bloch Sphere

Qubits (quantum bits) are two-state quantum systems. The quantum state of a qubit can be visualized as a point on the Bloch sphere. For a qubit prepared in a state , the probability of measuring the system to be in a second state, , can also be visualized on the Bloch sphere. The probability is proportional to the area of the complementary spherical cap obtained by rotating one Bloch vector around the other.

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