Create quantum_noise.py

quantum/libraries/quantum_noise.py

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+# quantum_noise.py
+import numpy as np
+from qiskit import QuantumCircuit, Aer, execute
+from qiskit.visualization import plot_histogram, plot_bloch_multivector
+from qiskit.providers.aer import AerSimulator
+from qiskit.providers.aer.noise import NoiseModel, depolarizing_error, amplitude_damping_error, phase_damping_error
+from qiskit.quantum_info import Statevector
+
+def create_noise_model(noise_type='depolarizing', noise_level=0.1):
+    """
+    Create a noise model based on the specified type and level.
+    
+    Parameters:
+    - noise_type: Type of noise ('depolarizing', 'amplitude_damping', 'phase_damping')
+    - noise_level: Level of noise (0 to 1)
+    
+    Returns:
+    - NoiseModel: The constructed noise model
+    """
+    noise_model = NoiseModel()
+
+    if noise_type == 'depolarizing':
+        error = depolarizing_error(noise_level, 1)  # 1-qubit depolarizing error
+        noise_model.add_all_qubit_quantum_error(error, ['h', 'cx', 'measure'])
+    elif noise_type == 'amplitude_damping':
+        error = amplitude_damping_error(noise_level)
+        noise_model.add_all_qubit_quantum_error(error, ['h', 'cx', 'measure'])
+    elif noise_type == 'phase_damping':
+        error = phase_damping_error(noise_level)
+        noise_model.add_all_qubit_quantum_error(error, ['h', 'cx', 'measure'])
+    else:
+        raise ValueError("Unsupported noise type. Choose from 'depolarizing', 'amplitude_damping', or 'phase_damping'.")
+
+    return noise_model
+
+def apply_noise_to_circuit(circuit, noise_model):
+    """
+    Apply a noise model to a quantum circuit.
+    
+    Parameters:
+    - circuit: QuantumCircuit object
+    - noise_model: NoiseModel object to apply
+    
+    Returns:
+    - QuantumCircuit: The circuit with noise applied
+    """
+    return circuit.decompose()  # Decompose the circuit to apply noise
+
+def run_circuit_with_noise(circuit, noise_model):
+    """
+    Run the quantum circuit with the specified noise model and return the results.
+    
+    Parameters:
+    - circuit: QuantumCircuit object
+    - noise_model: NoiseModel object to apply
+    
+    Returns:
+    - counts: Measurement results
+    - statevector: State vector of the quantum system
+    """
+    # Use the Aer's qasm_simulator
+    simulator = AerSimulator()
+
+    # Execute the circuit on the qasm simulator with noise
+    job = execute(circuit, simulator, shots=1024, noise_model=noise_model)
+    result = job.result()
+
+    # Get measurement counts
+    counts = result.get_counts(circuit)
+
+    # Get the state vector for visualization
+    statevector = Statevector.from_dict(counts)
+
+    return counts, statevector
+
+def visualize_results(counts, statevector):
+    """
+    Visualize the results of the noise simulation.
+    
+    Parameters:
+    - counts: Measurement results
+    - statevector: State vector of the quantum system
+    """
+    print("Counts:", counts)
+    plot_histogram(counts).show()
+    plot_bloch_multivector(statevector).show()
+
+if __name__ == "__main__":
+    # Example usage of the noise simulation functions
+    num_qubits = 2
+    circuit = QuantumCircuit(num_qubits, num_qubits)
+    circuit.h(0)  # Apply Hadamard to the first qubit
+    circuit.cx(0, 1)  # Apply CNOT to create entanglement
+    circuit.measure(range(num_qubits), range(num_qubits))  # Measure all qubits
+
+    # Create a noise model
+    noise_model = create_noise_model(noise_type='depolarizing', noise_level=0.1)
+
+    # Run the circuit with noise
+    counts, statevector = run_circuit_with_noise(circuit, noise_model)
+
+    # Visualize the results
+    visualize_results(counts, statevector)