Create fault_tolerant_circuit.py

quantum/circuits/fault_tolerant_circuit.py

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+# fault_tolerant_circuit.py
+import numpy as np
+from qiskit import QuantumCircuit, Aer, execute
+from qiskit.visualization import plot_histogram
+
+def create_fault_tolerant_circuit():
+    """
+    Create a quantum circuit for the Steane code (7-qubit code).
+    
+    Returns:
+    - QuantumCircuit: The constructed fault-tolerant circuit
+    """
+    circuit = QuantumCircuit(7, 7)  # 7 qubits for the Steane code and 7 classical bits for measurement
+
+    # Step 1: Encode the logical qubit |0> into the Steane code
+    circuit.h(0)  # Prepare the logical |+> state
+    circuit.cx(0, 1)
+    circuit.cx(0, 2)
+    circuit.cx(0, 3)
+    circuit.cx(0, 4)
+    circuit.cx(0, 5)
+    circuit.cx(0, 6)
+
+    # Step 2: Simulate a bit-flip error on one of the qubits (for demonstration)
+    circuit.x(1)  # Introduce an error on qubit 1
+
+    # Step 3: Error detection
+    # Measure the parity of the first three qubits
+    circuit.cx(1, 3)
+    circuit.cx(2, 3)
+    circuit.measure(3, 0)  # Measure parity into classical bit 0
+
+    # Measure the parity of the last four qubits
+    circuit.cx(4, 6)
+    circuit.cx(5, 6)
+    circuit.measure(6, 1)  # Measure parity into classical bit 1
+
+    # Step 4: Apply correction based on measurement results
+    circuit.x(1).c_if(circuit.clbits[0], 1)  # If parity is 1, flip qubit 1
+    circuit.x(2).c_if(circuit.clbits[1], 1)  # If parity is 1, flip qubit 2
+
+    # Step 5: Measure the logical qubit
+    circuit.measure(range(7), range(7))  # Measure all qubits
+
+    return circuit
+
+def run_fault_tolerant_simulation():
+    """
+    Run the fault-tolerant quantum computing simulation and return the results.
+    
+    Returns:
+    - counts: Measurement results
+    """
+    # Create the fault-tolerant circuit
+    circuit = create_fault_tolerant_circuit()
+
+    # Use the Aer's qasm_simulator
+    simulator = Aer.get_backend('qasm_simulator')
+
+    # Execute the circuit on the qasm simulator
+    job = execute(circuit, simulator, shots=1024)
+    result = job.result()
+
+    # Get measurement counts
+    counts = result.get_counts(circuit)
+
+    return counts
+
+def visualize_results(counts):
+    """
+    Visualize the results of the fault-tolerant simulation.
+    
+    Parameters:
+    - counts: Measurement results
+    """
+    print("Counts:", counts)
+    plot_histogram(counts).show()
+
+if __name__ == "__main__":
+    # Run the fault-tolerant simulation
+    counts = run_fault_tolerant_simulation()
+
+    # Visualize the results
+    visualize_results(counts)