The Future of Quantum Computing II

// Qubit teleportation quantum circuit simulator

#include <iostream>

#include <qpp/qpp.hpp>

int main() {
    using namespace qpp;

    std::cout << ">> Qubit teleportation quantum circuit simulation\n\n";

    // quantum circuit with 3 qubits and 2 classical bits
    QCircuit qc{3, 2};
    // set the qubit 0 to a random state
    cmat U = randU(2);
    // apply the gate U with name randU to qubit 0
    qc.gate(U, 0, "randU");

    // set the MES between qubits 1 and 2
    qc.gate(gt.H, 1);
    qc.CTRL(gt.X, 1, 2);

    // perform the Bell measurement between qubits 0 and 1
    qc.CTRL(gt.X, 0, 1);
    qc.gate(gt.H, 0);
    qc.measure({0, 1});

    // apply the classical controls
    qc.cCTRL(gt.X, 1, 2);
    qc.cCTRL(gt.Z, 0, 2);

    // initialize the quantum engine with the circuit
    QEngine engine{qc};

    // display the quantum circuit and its corresponding resources
    std::cout << qc << "\n\n" << qc.get_resources() << "\n\n";

    // execute the entire circuit
    engine.execute();

    // display the measurement statistics
    std::cout << engine << "\n\n";

    // verify that the teleportation was successful
    ket psi_in = U * 0_ket;
    ket psi_out = engine.get_state();
    std::cout << ">> Teleported state:\n";
    std::cout << disp(dirac(psi_out)) << '\n';
    std::cout << ">> Norm difference: " << norm(psi_out - psi_in) << '\n';
}