Quantum Circuit Simulator for JavaScript
A clean-room, zero-dependency state-vector quantum circuit simulator, written in pure JavaScript. Runs in the browser via plain <script> or in Node.js via require(). MIT licensed.
Install
npm install quantro-js— or load straight from unpkg in any page:
<script src="https://unpkg.com/quantro-js"></script>Quick start — a Bell pair
Two qubits, an H gate and a CNOT: that is entanglement. This is a real, reproducible run (seed 42):
const { QuantumCircuit, bellState, sampleDistribution } = require('quantro-js');
const qc = new QuantumCircuit(2);
bellState(qc); // |00> + |11>
console.log(qc.probabilities());
// [ 0.4999999999999999, 0, 0, 0.4999999999999999 ]
const counts = sampleDistribution(qc, 1024, 42);
console.log(counts);
// { 0: 494, 3: 530 } → measured half in |00>, half in |11>GHZ three-qubit state
Gates chain, and every method returns the circuit:
const qc = new QuantumCircuit(3);
qc.h(0).cx(0, 1).cx(0, 2); // GHZ state (|000> + |111>) / √2
console.log(qc.probabilities());
// [ 0.4999999999999999, 0, 0, 0, 0, 0, 0, 0.4999999999999999 ]Single measurement
const qc = new QuantumCircuit(1);
qc.h(0); // superposition
qc.measureAll(() => 0.1); // → 0
qc.measureAll(() => 0.9); // → 1API reference
| API | Description |
|---|---|
new QuantumCircuit(n) | n-qubit circuit (1 ≤ n ≤ 12, full 2ⁿ state vector) |
.h(q) · .x(q) · .y(q) · .z(q) | single-qubit gates (chainable) |
.ry(theta, q) | rotation around Y by theta radians |
.cx(c, t) · .cz(c, t) | controlled-X / controlled-Z (entanglement gates) |
.probabilities() | measurement probability distribution over the 2ⁿ basis states |
.measureAll(rng) | one sampled measurement (integer); rng = () => [0,1) |
bellState(qc) | prepare |00> + |11> (Bell pair) |
ghzState(qc, qubits) | prepare |0…0> + |1…1> (GHZ) |
sampleDistribution(qc, shots[, seed]) | sample counts; seeded → fully reproducible |
mulberry32(seed) | seeded PRNG generator |
H · X · Y · Z · I2 | gate matrices (complex-array form) |
Why it exists
quantro-js is the engine behind this site's 13 interactive tools. It was written from scratch as a community critique of the assumption that "quantum computing needs big frameworks": the whole simulator fits in one MIT-licensed, dependency-free JavaScript file, and it is deliberately kept humble and inspectable so that anyone — student, developer, researcher — can read, run and extend it.
Companion project: ZENAI (4 brains)
The same author maintains ZENAI — a Turkish, local-first AI assistant built on a two-tier brain setup (a local Ollama 7B/14B code model + a cloud "mega brain"), with a four-brain deliberation layer: majority vote, a 12-criteria jury referee, verification, and self-correction. The badge below tracks its repository automatically, so what you see always reflects the latest upstream commit.