If H creates a 50/50 readout, what happens when we apply it twice?
Exact probabilities are shown now. Run shots to see a finite sample.
Change one thing. See what moves.
Sweep a rotation angle or the noise strength. Plot what changes across 33 settings.
Export circuits for another session, or share a link to the exact setup.
Choose a question from the shelf. Make a prediction. Step through the gates, or change one and see what happens. Follow the learning path to review the basics and unlock advanced tools.
Open “Undo the randomness.” One person drives; someone else predicts. Use the play button to see each step. Add an M gate between the H gates and compare.
Switch to Go deeper. Build up to six qubits, set the input, inspect amplitudes and density matrices, test Pauli correlations, add noise, and sweep a parameter.
Use Share experiment to copy the setup and prediction into a link. Links do not create a live shared editing session. A classmate also needs access to this Site.
This is a classical browser simulation of 1–6 qubits, up to 80 operations. It computes a complex density matrix, so pure states, mixtures, and the supported noise channels use the same mathematics. It is not connected to quantum hardware.
Inputs start in a chosen computational basis state. q0 is the leftmost displayed bit. Gates run left to right, one operation per column. Rotation angles are radians. Shots sample all qubits in the Z basis at the selected step.
M performs a nonselective Z measurement on one qubit: the result is discarded. It removes that qubit’s off-diagonal blocks. It does not produce a retained classical bit, selected branch, or conditional feedback. Teleportation with classical feed-forward and adaptive circuits are not implemented.
Noise acts after each non-measurement gate on every qubit touched by that gate. Dephasing multiplies off-diagonal blocks by (1 − p); this is not the same p convention as a probabilistic Z flip. Bit flip is (1 − p)ρ + pXρX. Amplitude damping uses the standard decay channel toward 0 with probability p. These are independent toy channels, not calibrated hardware, timing, readout errors, or crosstalk.
A Bloch view is the reduced state of one qubit. It cannot show all multi-qubit correlations. Matching histograms alone do not establish entanglement or equal quantum states. Amplitudes are only displayed for a pure joint state, with an arbitrary global phase fixed for display.
Use ideal-circuit OpenQASM export to take circuits into larger tools. QASM export excludes noise and M gates to avoid changing their semantics. Qiskit typically prints measured bits in the reverse order from this lab. Larger systems, custom matrices, hardware jobs, and error correction workflows need a dedicated quantum SDK.
This link contains the circuit, selected step, settings, prediction, and observations. Anyone you send it to who has Site access can open a copy.
Each person edits their own copy. The link does not include the pinned comparison or unsaved changes.
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