The Quantum Classroom

Learn by changing one thing.

Build a circuit.
See the state.

Place gates on the wires, follow the state one column at a time, and discover the difference between superposition, phase, and entanglement.

Three things to try

Go beyond the histogram.

  1. Break a Bell pair. Load the Bell example and erase CX. The local states become pure, and |01⟩ appears.
  2. Make phase visible. Load phase interference. Remove Z between the two H gates and watch |1⟩ become |0⟩.
  3. Inspect entanglement. Step through GHZ. At the final column, each qubit has a 50/50 marginal, but the only joint outcomes are |000⟩ and |111⟩.