Simulator

Quantum Circuit Simulator

Build a circuit, run it, and read the state — all computed in your browser. The palette covers the standard set plus √X, Fredkin, a multi-controlled X with any number of controls, a custom 2×2 or 4×4 matrix with a unitarity check, barriers, and register blocks — +k mod N, ×k mod N and the QFT — which is what lets you assemble Shor’s order-finding circuit from parts. Everything exports to OpenQASM 3 that reads back exactly.

H selected — tap or click a wire, or Tab into the grid and use the arrow keys, then press Enter, to place it. Enter, Delete, or tapping a placed gate removes it.

Extra controls

None. The gate applies unconditionally, exactly as it always has, unless you add one.

Run this gateBind a gate to a measured bit to build teleportation, superdense coding, or a correcting error-correction round.

Pick a gate, then tap a cell — or Tab into the grid and use the arrow keys and Enter — to place it.

Shots

Readout noise0.0%Readout error: each measured bit is flipped with this probability

Presets

Press Run to sample this circuit.

State inspector

No gates

Just applied nothing yetNext end of circuit

No gates placed yet.

Phase disks

Each disk is one qubit: the filled area is its chance of reading 1, the needle points at the phase of its |1⟩ component, and the ring fades as entanglement mixes the qubit.

Per-qubit

q00.0%separable · 0.00
q10.0%separable · 0.00

P(1) is the chance this qubit reads 1; entropy is 0 when it stands alone and 1 when it is maximally entangled with the rest.

State

State	Amplitude	Prob.
\|00⟩	1.000	100.0%
\|01⟩	0.000	0.0%
\|10⟩	0.000	0.0%
\|11⟩	0.000	0.0%

OpenQASM 3

Export

OPENQASM 3.0;
include "stdgates.inc";

qubit[2] q;
bit[2] c;


c = measure q;

Edit (live)

Save & share

local storage

Place at least one gate to save.

Your circuits0 / 10 saved

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Export notebook

A ready-to-run Jupyter notebook of this circuit — open it in Colab or your own environment. Built in your browser; nothing leaves this page.

Cite this result

One file holding the OpenQASM 3 circuit, a JSON manifest of what was run with what, a BibTeX entry, and a README that says how to re-run it. No run is recorded yet — run the circuit to include its counts.

Research tools — exact, no sampling

Expectation value ⟨ψ|H|ψ⟩

Pauli sum, e.g. Z0 Z1, 0.5*X0X1 − 0.3*Y2, or a full label like ZI (rightmost letter = qubit 0, Qiskit order).

⟨H⟩ = 1.0

Final statevector

All 4 amplitudes at full double precision, with the bit-order convention written into the file. Loads directly into NumPy, pandas or Qiskit’s Statevector.

Export circuit image

2 qubits · a black/white diagram for printing or pasting into a paper. LaTeX needs the quantikz package to compile.