Qoffee-Maker

Build a quantum circuit, measure it, and get the drink the measurement chose. Each beverage is a bit pattern — 000, 001, 010 … — so ordering a cappuccino means constructing a circuit whose measurement lands on the right one. Quantum mechanics being what it is, you can shift the odds but never quite give an order.

Qoffee Maker

Needs: a display · a network connection · Start it with: rq_demo_run.sh qoffee-maker

Run it

Open the Big projects folder on the desktop and double-click Qoffee-Maker. It starts the Qoffee container, opens qoffee.ipynb, and switches straight into the app view — you do not have to run any cells yourself.

It is also under Applications → RasQberry → Qoffee-Maker, or in sudo raspi-config → 0 RasQberry → Quantum Demos → Big projects.

The first launch pulls the Qoffee container image, so give it a few minutes and a decent connection. After that it starts quickly.

If you end up looking at the notebook instead of the app — the auto-start did not take, or you opened qoffee.ipynb yourself — click the rocket icon (🚀) in the toolbar. That runs every cell and starts the app view, which is exactly what the icon does for you.

What you'll see

Qoffee Maker Demo Interface

Drag gates onto the qubits to build a circuit. The interface shows the probability of each of the eight outcomes, and which drink each one pours. Choose a backend to compare an ideal simulation against one with realistic noise — the noisy run is the honest one, and it is a good way to feel what error means in practice before anyone mentions error correction.

Beverage Overview

Start by aiming for an outcome you can hit reliably (000, or 111), then try for a specific drink in the middle. That is where it gets interesting: superposition means your circuit sets probabilities, so you may need a few attempts — which is the point of the demo.

With a Home Connect coffee machine, the winning measurement actually brews it: register an application as in the Qoffee-Maker README, then put its client ID and secret, and HOMECONNECT_API_URL=https://api.home-connect.com/, into ~/RasQberry-Two/demos/Qoffee-Maker/.env. Without one, everything works except the coffee.

Credits and documentation

By Max Simon and Jan-R. Lahmann, from the "serious games for quantum computing" family. Full details, the hardware setup and the event kit are on the project's own site:

See the Demo List for everything else on the image.

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