# Episode 03: Prepare an entangled state

A pair alone is not enough

## Narration script

Start with two qubits in zero. Applying H to the first creates a superposition. The controlled-NOT then correlates the qubits in a Bell state. This is a mathematical circuit demonstration. A physical photon source must prepare an appropriate joint state; producing two photons does not automatically entangle them. Shorter wavelength means more photon energy, not faster vacuum propagation or guaranteed stronger entanglement. Making a chip and cooling some devices for operation are separate processes.

## Exact footage

Capture step 3 at start, H, and H followed by CNOT. Frame the four outcome probabilities. Add a title card showing E=hc/λ and “same speed in vacuum”.

## Recording steps

1. Use a clean browser profile and 1920×1080 capture; enable a visible cursor.
2. Record the introduction, then the listed demo in one deliberate pass.
3. Pause on each prediction before showing the output; record narration separately if needed.
4. Review captions, mathematical symbols and scientific claims against the sources.
5. Check for private data; export a local draft. Publishing requires a separate decision.

## Acceptance

Correct preparation sequence, and no claims of creating physical entanglement.

Status: prepared script and generated SVG thumbnail; footage not recorded, video not published.