Curriculum / Quantum Foundations / Measuring in Different Bases
Measuring in Different Bases
Code challenge: prepare states and measure in the X and Y bases.
Measuring in Different Bases
The |+⟩ state is (|0⟩ + |1⟩)/√2. If we measure it in the Z-basis we get 50/50 random results. But if we measure in the X-basis (apply H first), we get |0⟩ deterministically.
Your Challenge
- 1.Create the |+⟩ state using H on qubit 0
- 2.Measure in the X-basis (apply H then measure), you should get 100% "0"
- 3.Create |−⟩ = (|0⟩ − |1⟩)/√2 using H then Z
- 4.Measure in the X-basis, you should get 100% "1"
Compare both results to show that X-basis measurement distinguishes |+⟩ and |−⟩ perfectly.
How this lesson works
A hands-on coding challenge. You write Qiskit-compatible Python in the browser editor, run it instantly via WebAssembly, watch the circuit and Bloch sphere react, and pass automatic output checks. The AI tutor Qubitus gives Socratic hints if you get stuck.
Part of: Quantum Foundations
Learn the basics: qubits, gates, superposition, and measurement.
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