open-standards/wai/wai-quantum/course/lessons/ghz/lesson.en.md
Transaction Science fb230d8a62 wai-quantum: the circuits course as data, each exercise checked by the engine, and wai-quantum learn in English and Chinese
engine::course reads the course from wai-quantum/course/: 21 lessons from a
first circuit through superposition, entanglement, interference, the standard
algorithms, noise and mitigation, error correction and fault tolerance to
resource estimates, each a Markdown text in English and Simplified Chinese and
an exercise.json with a schema. A check runs each case of an exercise (a
generator's inputs) with its intent and the verdict, measures its constraints
(the gates allowed, counts, the T count, the critique's smells, the resource
estimate's counts), and says what went wrong from the diagnostics, the verdict
and the critique, never from the solution. The tests hold every solution to
pass by proof, every known wrong answer to fail for its stated reason, and
every locale to every text and message.

wai-quantum learn shows, starts, checks, hints and explains a lesson, keeps
progress only on this machine, and speaks the language --lang or LANG names;
the command summaries and docs topics have Chinese translations held to the
English they came from. The verdict gains of_diagnostic for a generator's
refusal. llms.txt names the course.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
2026-10-28 08:42:54 -04:00

21 lines
1 KiB
Markdown
Raw Permalink Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

The *GHZ state* (|000⟩ + |111⟩)/√2 extends the Bell pair to three qubits: all agree, all 0 or all 1.
Two states can give the same outcomes and still differ. (|000⟩ − |111⟩)/√2 measures exactly like the GHZ state, but the minus sign is a *relative phase* between its two parts, and a later gate can turn that phase into a different outcome. A distribution cannot see it.
So this exercise states its intent as a state: *prepares*. The engine runs your program and its own reference from |0…0⟩ and compares the two states up to a global phase (a phase on the whole state, which no measurement can see), and the verdict is a proof. Two programs can prepare the same state and still be different circuits, so more than one answer passes.
On the command line an intent is a file:
```sh runnable
cat > pair.qasm <<'QASM'
OPENQASM 3.0;
include "stdgates.inc";
qubit[2] q;
bit[2] c;
h q[0];
cx q[0], q[1];
c = measure q;
QASM
echo '{"distribution": {"00": 0.5, "11": 0.5}}' > pair-intent.json
wai-quantum run pair.qasm --intent pair-intent.json --shots 100
```