#include <iostream>
#include <complex>
#include <iomanip>
#include <cstdlib>
#include <ctime>
const double PI = 3.141592653589793;
// A complex number type for quantum amplitudes
using Complex = std::complex<double>;
// Class to represent a Qubit
class Qubit {
public:
Qubit(double theta) {
// Initialize the qubit state with angles theta and phi
alpha = std::cos(theta / 2);
beta = std::sin(theta / 2) * std::exp(Complex(0, 2 * PI * std::rand() / RAND_MAX));
}
// Print the state of the qubit
void printState() const {
std::cout << "Qubit State: ";
std::cout << std::fixed << std::setprecision(2)
<< "|" << alpha << "|0> + " << beta << "|1>" << std::endl;
}
// Measure the qubit state
int measure() const {
// Compute probabilities
double prob0 = std::norm(alpha);
double prob1 = std::norm(beta);
// Print probabilities
std::cout << "Probability of |0>: " << prob0 << std::endl;
std::cout << "Probability of |1>: " << prob1 << std::endl;
// Randomly choose the measurement outcome based on probabilities
double rand_val = static_cast<double>(std::rand()) / RAND_MAX;
return rand_val < prob0 ? 0 : 1;
}
private:
Complex alpha; // Amplitude for |0>
Complex beta; // Amplitude for |1>
};
int main() {
// Seed the random number generator
std::srand(static_cast<unsigned>(std::time(nullptr)));
double theta;
std::cout << "Enter the angle theta (in radians) for the qubit state: ";
std::cin >> theta;
Qubit qubit(theta);
qubit.printState();
int measurement = qubit.measure();
std::cout << "Measurement result: |" << measurement << ">" << std::endl;
return 0;
}
