Unlike classical bits that exist as either 0 or 1, qubits can exist in a superposition of both states simultaneously. This is described mathematically as |ψ⟩ = α|0⟩ + β|1⟩, where α and β are complex probability amplitudes with |α|² + |β|² = 1.

What is a Qubit?

A qubit is typically represented as a point on the Bloch sphere. The north pole represents |0⟩ and the south pole |1⟩. Any point on the surface represents a valid qubit state.

Superposition Explained

When we measure a qubit in superposition, it collapses to |0⟩ with probability |α|² or |1⟩ with probability |β|². Before measurement, the qubit genuinely exists in both states simultaneously — this is not just classical uncertainty.

Why It Matters

Superposition is what gives quantum computers their potential for exponential speedup on certain problems. With n qubits, a quantum computer can represent 2ⁿ states at once.