quaco.js/src/QuantumGate.js

A lightweight modular Quantum Computing Simulator in JavaScript. Supports qubits, quantum gates, entanglement, circuits, algorithms, and visualization.

// src/QuantumGate.js

import { Complex } from './utils/Complex.js';

/**
 * Static class providing common quantum gates.
 */
export class QuantumGate {
    /**
     * Identity Gate (I)
     * Leaves the qubit unchanged.
     */
    static identity() {
        return [
            [new Complex(1, 0), new Complex(0, 0)],
            [new Complex(0, 0), new Complex(1, 0)]
        ];
    }

    /**
     * Pauli-X Gate (NOT gate)
     * Flips |0⟩ to |1⟩ and vice-versa.
     */
    static x() {
        return [
            [new Complex(0, 0), new Complex(1, 0)],
            [new Complex(1, 0), new Complex(0, 0)]
        ];
    }

    /**
     * Pauli-Y Gate
     * Applies a phase flip and bit flip.
     */
    static y() {
        return [
            [new Complex(0, 0), new Complex(0, -1)],
            [new Complex(0, 1), new Complex(0, 0)]
        ];
    }

    /**
     * Pauli-Z Gate
     * Applies a phase flip to |1⟩ state.
     */
    static z() {
        return [
            [new Complex(1, 0), new Complex(0, 0)],
            [new Complex(0, 0), new Complex(-1, 0)]
        ];
    }

    /**
     * Hadamard Gate (H)
     * Creates superposition.
     */
    static hadamard() {
        const factor = 1 / Math.sqrt(2);
        return [
            [new Complex(factor, 0), new Complex(factor, 0)],
            [new Complex(factor, 0), new Complex(-factor, 0)]
        ];
    }

    /**
     * Phase Gate (S Gate)
     * Adds a π/2 phase to |1⟩.
     */
    static s() {
        return [
            [new Complex(1, 0), new Complex(0, 0)],
            [new Complex(0, 0), new Complex(0, 1)]
        ];
    }

    /**
     * T Gate (π/4 phase gate)
     */
    static t() {
        const sqrtHalf = Math.sqrt(0.5);
        return [
            [new Complex(1, 0), new Complex(0, 0)],
            [new Complex(0, 0), new Complex(sqrtHalf, sqrtHalf)]
        ];
    }

    /**
     * Controlled-NOT Gate (CNOT)
     * 2-qubit gate flipping target qubit if control is |1⟩.
     * Returns a 4x4 matrix.
     */
    static cnot() {
        return [
            [new Complex(1, 0), new Complex(0, 0), new Complex(0, 0), new Complex(0, 0)],
            [new Complex(0, 0), new Complex(1, 0), new Complex(0, 0), new Complex(0, 0)],
            [new Complex(0, 0), new Complex(0, 0), new Complex(0, 0), new Complex(1, 0)],
            [new Complex(0, 0), new Complex(0, 0), new Complex(1, 0), new Complex(0, 0)],
        ];
    }
}