Experiments, Games,
and More

Quantum key distribution · Ekert 91

Two students share a secret key using entangled qubits. The instant someone tries to listen in, you can tell. This is the protocol behind quantum-secure communication.

Learn about Qubits

Understand what qubits are, where they can be found in nature, and how we can use them to build new technologies.

Singlet state

Prepare two qubits so that measuring one tells you the answer for the other, in any basis. Once you have this, the rest of entanglement clicks.

The Born rule

Run a circuit a bunch of times, count the outcomes, work out the rule yourself. Way more convincing than being told.

Quantum random number generator

Quantum is the only source of true randomness we know of.

Learn how quantum programs are written, and learn their basic operations.

Learn how quantum programs are written, and learn their basic operations.

Play gates in rhythm

Guitar Hero, but for quantum gates. Apply rotations in time with a song. A surprisingly good way to memorize the gate set.

The watched pot doesn't boil

Learn about how observing a qubit can change its behavior. In this case, freezing it in place!

Alternative visualizations

Swap between Bloch spheres, density plots, and hue maps. Each highlights a different feature of the same quantum state.

IBM · IonQ · Quantinuum

Send your Qubi circuit to real hardware in IBM's, IonQ's, or Quantinuum's labs. The same circuit runs differently on superconducting hardware than on trapped ions, and the differences tell you a lot.

The 2022 Nobel-winning test of reality

The 2022 Physics Nobel went to people who ran this experiment. You measure correlations that no local theory can produce, and the math is right there in your hand.

Prove nonlocality in one shot

Set up three entangled qubits and you get an outcome that simply can't happen if each qubit had a definite answer before you measured. No statistics, no probabilities, just a flat contradiction with classical thinking.

Observer paradox

What happens if someone measures a qubit, and someone else measures the whole lab? On Qubi you can run both, and the answers are weirdly hard to reconcile.

T1, T2, and gate fidelity

Compare how noise affects different quantum computers differently.

Deutsch's algorithm

The first quantum algorithm to beat anything classical, even though the problem is a toy. Worth running because it's where the whole field starts.

Superdense coding

The mirror of teleportation. Use entanglement to compress 2 bits into 1!

Qubi acts like the world's most sensitive compass

Use accumulated phase to spot changes too small for any classical sensor. Same principle as LIGO and atomic gyroscopes.

The most precise clock humans have ever built

Why atomic clocks lose less than a second per billion years. Learn the Ramsey sequence on your Qubi.

Nuclear magnetic resonance

An MRI is already a quantum device. The same pulse sequences run on your Qubi as in a radiologist's spin-echo scan.

Noise mimicking mode

Configure your Qubi to behave like IBM, IonQ, or Quantinuum's hardware, noise and all. Run a circuit on a pretend machine and feel why noise still matters.

Quantum algorithm playground

Pause, rewind, and inspect any quantum algorithm gate by gate. Break it on purpose with noise or stray operations to see exactly how it fails.

Shor's algorithm

Factor 15 using period-finding. Give the same algorithm enough qubits and it breaks RSA. The only missing piece is scale.

Variational quantum eigensolver

Find the ground-state energy of H₂ by tweaking a circuit until the answer settles. This is what people use today's noisy quantum computers for.

The no-signaling theorem

Entangled qubits look like they should let you signal faster than light. Run the experiment that shows why they don't, and where the "spooky action" intuition fails.

Arbitrary time evolution

Define a Hamiltonian, hit play, and watch your qubits evolve under it. The starting point for optimization algorithms and quantum simulation. Bonus: leave it running as a screensaver.

Stabilizer codes and syndromes

Perform stabilizer measurements and watch error syndromes light up. See how a quantum error-correcting code spots and fixes errors as they happen.