Qiskit Backend Integration¶
Qiskit is IBM's open-source quantum computing framework that provides access to quantum simulators and real IBM quantum hardware. SuperQuantX integrates seamlessly with Qiskit to provide access to IBM's quantum ecosystem.
Overview¶
The Qiskit backend in SuperQuantX offers:
- IBM Quantum Hardware Access: Connect to real IBM quantum computers
- High-Performance Simulators: Use Qiskit Aer simulators
- Noise Models: Simulate realistic quantum device noise
- Quantum Circuits: Native Qiskit circuit manipulation
- Job Management: Automatic job queue handling
Installation¶
# Install SuperQuantX with Qiskit support
pip install superquantx[qiskit]
# Or install Qiskit directly
pip install qiskit qiskit-aer qiskit-ibm-runtime
Quick Start¶
Basic Usage¶
import superquantx as sqx
# Get Qiskit backend
backend = sqx.get_backend('qiskit')
print(f"Backend: {backend}")
# Create Bell state circuit
circuit = backend.create_circuit(2)
circuit.h(0)
circuit.cx(0, 1)
circuit.measure_all()
# Execute on simulator
result = backend.run(circuit, shots=1000)
print(f"Bell state results: {result.get_counts()}")
IBM Quantum Hardware¶
# Connect to IBM Quantum
from qiskit_ibm_runtime import QiskitRuntimeService
# Save your credentials (one-time setup)
QiskitRuntimeService.save_account(
channel="ibm_quantum",
token="YOUR_IBM_QUANTUM_TOKEN",
overwrite=True
)
# Use IBM Quantum backend
backend = sqx.QiskitBackend(
backend_name='ibmq_qasm_simulator', # or real hardware like 'ibm_osaka'
shots=1024
)
# Execute on IBM hardware
result = backend.run(circuit, shots=1024)
Configuration Options¶
Backend Selection¶
# Different Qiskit backends
backends = {
'qasm_simulator': 'Classical QASM simulator',
'statevector_simulator': 'Statevector simulator',
'unitary_simulator': 'Unitary matrix simulator',
'ibmq_qasm_simulator': 'IBM cloud simulator',
'ibm_osaka': 'IBM quantum processor (127 qubits)',
'ibm_kyoto': 'IBM quantum processor (127 qubits)'
}
# Create backend with specific device
backend = sqx.QiskitBackend(
backend_name='qasm_simulator',
shots=2048,
optimization_level=3
)
Advanced Configuration¶
# Custom backend configuration
backend = sqx.QiskitBackend(
backend_name='qasm_simulator',
shots=1000,
optimization_level=2, # 0-3, higher = more optimization
seed_simulator=42, # For reproducible results
max_parallel_threads=4,
memory=True, # Enable memory snapshots
noise_model=None # Custom noise model
)
# Access underlying Qiskit backend
qiskit_backend = backend.backend
print(f"Backend configuration: {qiskit_backend.configuration()}")
Working with Circuits¶
Circuit Creation¶
def demonstrate_qiskit_circuits():
"""Show various Qiskit circuit features."""
backend = sqx.get_backend('qiskit')
# Create 4-qubit circuit
circuit = backend.create_circuit(4)
# Single qubit gates
circuit.h(0) # Hadamard
circuit.x(1) # Pauli-X
circuit.y(2) # Pauli-Y
circuit.z(3) # Pauli-Z
# Rotation gates
import numpy as np
circuit.rx(np.pi/4, 0) # X rotation
circuit.ry(np.pi/3, 1) # Y rotation
circuit.rz(np.pi/6, 2) # Z rotation
# Two-qubit gates
circuit.cx(0, 1) # CNOT
circuit.cz(1, 2) # Controlled-Z
circuit.swap(2, 3) # SWAP
# Multi-controlled gates
circuit.ccx(0, 1, 2) # Toffoli (CCX)
# Phase gates
circuit.s(0) # S gate (√Z)
circuit.t(1) # T gate (√S)
# Measure all qubits
circuit.measure_all()
# Execute circuit
result = backend.run(circuit, shots=1000)
print(f"Complex circuit results: {result.get_counts()}")
# Visualize circuit (if available)
try:
print(circuit.draw())
except:
print("Circuit visualization not available")
demonstrate_qiskit_circuits()
Parameterized Circuits¶
def qiskit_parameterized_circuits():
"""Demonstrate parameterized quantum circuits."""
backend = sqx.get_backend('qiskit')
# Create parameterized circuit for VQE
def create_ansatz(params, n_qubits=4, layers=2):
circuit = backend.create_circuit(n_qubits)
param_idx = 0
# Initial layer
for i in range(n_qubits):
circuit.ry(params[param_idx], i)
param_idx += 1
# Entangling layers
for layer in range(layers):
# CNOT ladder
for i in range(n_qubits - 1):
circuit.cx(i, i + 1)
# Parameterized rotations
for i in range(n_qubits):
circuit.ry(params[param_idx], i)
param_idx += 1
circuit.rz(params[param_idx], i)
param_idx += 1
return circuit
# Generate random parameters
n_params = 4 + 2 * 2 * 4 # Initial + layers * 2 * qubits
params = np.random.random(n_params) * 2 * np.pi
# Create and run ansatz
ansatz = create_ansatz(params)
ansatz.measure_all()
result = backend.run(ansatz, shots=1000)
print(f"Parameterized circuit results: {result.get_counts()}")
# Parameter sensitivity analysis
print("\nParameter Sensitivity Analysis:")
base_result = result.get_counts()
base_prob_00 = base_result.get('0000', 0) / 1000
# Vary first parameter
for delta in [-0.1, -0.05, 0.05, 0.1]:
test_params = params.copy()
test_params[0] += delta
test_circuit = create_ansatz(test_params)
test_circuit.measure_all()
test_result = backend.run(test_circuit, shots=1000)
test_counts = test_result.get_counts()
test_prob_00 = test_counts.get('0000', 0) / 1000
print(f" Δθ = {delta:+.2f}: P(0000) = {test_prob_00:.3f} "
f"(change: {test_prob_00 - base_prob_00:+.3f})")
qiskit_parameterized_circuits()
IBM Quantum Hardware¶
Real Hardware Execution¶
def run_on_ibm_hardware():
"""Execute circuits on real IBM quantum hardware."""
# Note: Requires IBM Quantum account setup
try:
from qiskit_ibm_runtime import QiskitRuntimeService
# Initialize service
service = QiskitRuntimeService(channel="ibm_quantum")
# List available backends
available_backends = service.backends()
print("Available IBM Quantum backends:")
for backend in available_backends:
status = backend.status()
print(f" {backend.name}: {status.pending_jobs} jobs pending, "
f"operational: {status.operational}")
# Select least busy backend
from qiskit_ibm_runtime.utils import least_busy
backend_name = least_busy(available_backends).name
print(f"\nUsing backend: {backend_name}")
# Create SuperQuantX backend for IBM hardware
sqx_backend = sqx.QiskitBackend(
backend_name=backend_name,
shots=1024,
optimization_level=3 # Max optimization for hardware
)
# Create simple Bell state
circuit = sqx_backend.create_circuit(2)
circuit.h(0)
circuit.cx(0, 1)
circuit.measure_all()
print("Submitting job to IBM Quantum...")
result = sqx_backend.run(circuit, shots=1024)
counts = result.get_counts()
print(f"Hardware results: {counts}")
# Analyze fidelity
prob_00 = counts.get('00', 0) / 1024
prob_11 = counts.get('11', 0) / 1024
bell_fidelity = prob_00 + prob_11
print(f"Bell state fidelity: {bell_fidelity:.3f}")
# Compare with ideal
if bell_fidelity > 0.8:
print("✅ Good Bell state fidelity")
elif bell_fidelity > 0.6:
print("⚠️ Moderate Bell state fidelity")
else:
print("❌ Low Bell state fidelity")
except ImportError:
print("IBM Quantum access requires: pip install qiskit-ibm-runtime")
except Exception as e:
print(f"IBM Quantum access error: {e}")
print("Make sure to set up IBM Quantum credentials")
# Uncomment to run with proper IBM Quantum setup
# run_on_ibm_hardware()
Device Calibration Data¶
def analyze_device_properties():
"""Analyze IBM quantum device properties and calibration data."""
try:
from qiskit_ibm_runtime import QiskitRuntimeService
service = QiskitRuntimeService(channel="ibm_quantum")
backend = service.get_backend('ibm_osaka') # 127-qubit processor
# Get backend properties
properties = backend.properties()
configuration = backend.configuration()
print(f"Backend: {backend.name}")
print(f"Number of qubits: {configuration.n_qubits}")
print(f"Coupling map: {len(configuration.coupling_map)} connections")
# Analyze qubit properties
if properties:
print("\nQubit Error Rates:")
for i in range(min(10, configuration.n_qubits)): # First 10 qubits
# T1 and T2 times
t1 = properties.t1(i)
t2 = properties.t2(i)
# Readout error
readout_error = properties.readout_error(i)
# Gate error (single qubit)
try:
sx_error = properties.gate_error('sx', i)
print(f" Qubit {i}: T1={t1:.1f}μs, T2={t2:.1f}μs, "
f"Readout={readout_error:.4f}, SX={sx_error:.4f}")
except:
print(f" Qubit {i}: T1={t1:.1f}μs, T2={t2:.1f}μs, "
f"Readout={readout_error:.4f}")
# Two-qubit gate errors
print("\nTwo-Qubit Gate Errors:")
coupling_map = configuration.coupling_map
for i, (q1, q2) in enumerate(coupling_map[:10]): # First 10 pairs
try:
cx_error = properties.gate_error('cx', [q1, q2])
print(f" CX({q1},{q2}): {cx_error:.4f}")
except:
continue
# Create noise model for simulation
from qiskit_aer.noise import NoiseModel
noise_model = NoiseModel.from_backend(backend)
print(f"\nNoise model created with {len(noise_model.noise_instructions)} "
f"noise instructions")
# Use noise model in simulation
sqx_backend = sqx.QiskitBackend(
backend_name='qasm_simulator',
noise_model=noise_model,
shots=1000
)
# Test with Bell state
circuit = sqx_backend.create_circuit(2)
circuit.h(0)
circuit.cx(0, 1)
circuit.measure_all()
print("\nTesting with device noise model:")
noisy_result = sqx_backend.run(circuit, shots=1000)
noisy_counts = noisy_result.get_counts()
print(f"Noisy simulation: {noisy_counts}")
# Calculate noise impact
prob_00 = noisy_counts.get('00', 0) / 1000
prob_11 = noisy_counts.get('11', 0) / 1000
prob_01 = noisy_counts.get('01', 0) / 1000
prob_10 = noisy_counts.get('10', 0) / 1000
fidelity = prob_00 + prob_11
error_rate = prob_01 + prob_10
print(f"Bell state fidelity with noise: {fidelity:.3f}")
print(f"Error rate: {error_rate:.3f}")
except Exception as e:
print(f"Device analysis requires IBM Quantum access: {e}")
# Uncomment to run with IBM Quantum access
# analyze_device_properties()
Advanced Features¶
Transpilation and Optimization¶
def demonstrate_transpilation():
"""Show Qiskit circuit transpilation and optimization."""
backend = sqx.get_backend('qiskit')
# Create complex circuit that needs optimization
circuit = backend.create_circuit(5)
# Add many gates that can be optimized
for i in range(5):
circuit.h(i)
for i in range(4):
circuit.cx(i, i + 1)
# Add more layers
for _ in range(3):
for i in range(5):
circuit.rz(np.pi/4, i)
for i in range(4):
circuit.cx(i, i + 1)
circuit.measure_all()
print("Original circuit stats:")
print(f" Gates: {len(circuit._circuit.data) if hasattr(circuit, '_circuit') else 'N/A'}")
# Test different optimization levels
optimization_levels = [0, 1, 2, 3]
for opt_level in optimization_levels:
opt_backend = sqx.QiskitBackend(
backend_name='qasm_simulator',
optimization_level=opt_level,
shots=1000
)
# Execute with optimization
result = opt_backend.run(circuit, shots=1000)
counts = result.get_counts()
print(f"\nOptimization level {opt_level}:")
print(f" Result distribution: {len(counts)} unique outcomes")
print(f" Most probable: {max(counts.keys(), key=counts.get)} "
f"({max(counts.values())/1000:.3f})")
demonstrate_transpilation()
Custom Noise Models¶
def create_custom_noise_models():
"""Create and use custom noise models."""
try:
from qiskit_aer.noise import (NoiseModel, depolarizing_error,
thermal_relaxation_error, ReadoutError)
# Create custom noise model
noise_model = NoiseModel()
# Single-qubit gate errors
single_qubit_error = depolarizing_error(0.001, 1) # 0.1% error rate
noise_model.add_all_qubit_quantum_error(single_qubit_error, ['u1', 'u2', 'u3'])
# Two-qubit gate errors
two_qubit_error = depolarizing_error(0.01, 2) # 1% error rate
noise_model.add_all_qubit_quantum_error(two_qubit_error, ['cx'])
# Thermal relaxation
t1 = 50000 # T1 time (ns)
t2 = 70000 # T2 time (ns)
for qubit in range(5): # Apply to 5 qubits
thermal_error = thermal_relaxation_error(t1, t2, 35) # 35ns gate time
noise_model.add_quantum_error(thermal_error, ['u1', 'u2', 'u3'], [qubit])
# Readout errors
readout_error = ReadoutError([[0.95, 0.05], [0.1, 0.9]]) # Asymmetric readout
noise_model.add_all_qubit_readout_error(readout_error)
print("Custom noise model created:")
print(f" Quantum errors: {len(noise_model.noise_instructions)}")
print(f" Readout errors: {len(noise_model._default_readout_errors)}")
# Use custom noise model
backend = sqx.QiskitBackend(
backend_name='qasm_simulator',
noise_model=noise_model,
shots=2000
)
# Test various circuits
test_circuits = {
'Single H': lambda: backend.create_circuit(1).h(0).measure_all(),
'Bell State': lambda: backend.create_circuit(2).h(0).cx(0,1).measure_all(),
'GHZ State': lambda: backend.create_circuit(3).h(0).cx(0,1).cx(1,2).measure_all()
}
print("\nNoise impact analysis:")
for name, circuit_func in test_circuits.items():
# Noiseless simulation
clean_backend = sqx.QiskitBackend(backend_name='qasm_simulator', shots=2000)
clean_circuit = circuit_func()
clean_result = clean_backend.run(clean_circuit, shots=2000)
clean_counts = clean_result.get_counts()
# Noisy simulation
noisy_circuit = circuit_func()
noisy_result = backend.run(noisy_circuit, shots=2000)
noisy_counts = noisy_result.get_counts()
# Compare fidelities
if name == 'Single H':
# Expected: 50-50 distribution
clean_fidelity = min(clean_counts.get('0', 0), clean_counts.get('1', 0)) / 1000
noisy_fidelity = min(noisy_counts.get('0', 0), noisy_counts.get('1', 0)) / 1000
else:
# Expected: only |00..0⟩ and |11..1⟩
all_zeros = '0' * (2 if 'Bell' in name else 3)
all_ones = '1' * (2 if 'Bell' in name else 3)
clean_fidelity = (clean_counts.get(all_zeros, 0) +
clean_counts.get(all_ones, 0)) / 2000
noisy_fidelity = (noisy_counts.get(all_zeros, 0) +
noisy_counts.get(all_ones, 0)) / 2000
fidelity_loss = clean_fidelity - noisy_fidelity
print(f" {name}:")
print(f" Clean fidelity: {clean_fidelity:.3f}")
print(f" Noisy fidelity: {noisy_fidelity:.3f}")
print(f" Fidelity loss: {fidelity_loss:.3f}")
except ImportError:
print("Noise modeling requires: pip install qiskit-aer")
create_custom_noise_models()
Error Mitigation¶
def demonstrate_error_mitigation():
"""Show error mitigation techniques with Qiskit."""
try:
from qiskit_aer.noise import NoiseModel, depolarizing_error
# Create noisy backend
noise_model = NoiseModel()
error = depolarizing_error(0.02, 1) # 2% single-qubit error
noise_model.add_all_qubit_quantum_error(error, ['u1', 'u2', 'u3'])
noisy_backend = sqx.QiskitBackend(
backend_name='qasm_simulator',
noise_model=noise_model,
shots=2000
)
# Test circuit: |+⟩ state
def create_plus_state():
circuit = noisy_backend.create_circuit(1)
circuit.h(0)
circuit.measure_all()
return circuit
# 1. Zero-noise extrapolation
print("Error Mitigation: Zero-Noise Extrapolation")
noise_factors = [1, 2, 3] # Amplify noise by these factors
expectation_values = []
for factor in noise_factors:
# Amplify noise by repeating gates
circuit = noisy_backend.create_circuit(1)
# Apply H gate 'factor' times (odd repetitions = H, even = I)
for _ in range(factor):
circuit.h(0)
# If even number of H gates, apply one more to get |+⟩
if factor % 2 == 0:
circuit.h(0)
circuit.measure_all()
result = noisy_backend.run(circuit, shots=2000)
counts = result.get_counts()
# Expectation value of |+⟩ state
prob_0 = counts.get('0', 0) / 2000
expectation = 2 * prob_0 - 1 # Convert to [-1, 1]
expectation_values.append(expectation)
print(f" Noise factor {factor}: <Z> = {expectation:.3f}")
# Extrapolate to zero noise
# Fit linear model and extrapolate to factor=0
import numpy as np
coeffs = np.polyfit(noise_factors, expectation_values, 1)
zero_noise_value = coeffs[1] # y-intercept
print(f" Extrapolated zero-noise: <Z> = {zero_noise_value:.3f}")
print(f" Theoretical value: <Z> = 0.000")
print(f" Error correction: {abs(zero_noise_value):.3f}")
# 2. Readout error mitigation
print(f"\nError Mitigation: Readout Correction")
# Calibrate readout errors
def calibrate_readout():
# Measure |0⟩ state
circuit_0 = noisy_backend.create_circuit(1)
circuit_0.measure_all()
result_0 = noisy_backend.run(circuit_0, shots=1000)
counts_0 = result_0.get_counts()
# Measure |1⟩ state
circuit_1 = noisy_backend.create_circuit(1)
circuit_1.x(0) # Prepare |1⟩
circuit_1.measure_all()
result_1 = noisy_backend.run(circuit_1, shots=1000)
counts_1 = result_1.get_counts()
# Build calibration matrix
p00 = counts_0.get('0', 0) / 1000 # P(measure 0 | prepared 0)
p01 = counts_0.get('1', 0) / 1000 # P(measure 1 | prepared 0)
p10 = counts_1.get('0', 0) / 1000 # P(measure 0 | prepared 1)
p11 = counts_1.get('1', 0) / 1000 # P(measure 1 | prepared 1)
calibration_matrix = np.array([[p00, p10], [p01, p11]])
return calibration_matrix
cal_matrix = calibrate_readout()
print(f" Calibration matrix:")
print(f" [[{cal_matrix[0,0]:.3f}, {cal_matrix[0,1]:.3f}],")
print(f" [{cal_matrix[1,0]:.3f}, {cal_matrix[1,1]:.3f}]]")
# Test readout correction
test_circuit = create_plus_state()
raw_result = noisy_backend.run(test_circuit, shots=1000)
raw_counts = raw_result.get_counts()
# Apply correction
raw_probs = np.array([
raw_counts.get('0', 0) / 1000,
raw_counts.get('1', 0) / 1000
])
corrected_probs = np.linalg.inv(cal_matrix) @ raw_probs
print(f" Raw probabilities: [P(0)={raw_probs[0]:.3f}, P(1)={raw_probs[1]:.3f}]")
print(f" Corrected probs: [P(0)={corrected_probs[0]:.3f}, P(1)={corrected_probs[1]:.3f}]")
print(f" Theoretical: [P(0)=0.500, P(1)=0.500]")
# Calculate improvement
raw_error = abs(raw_probs[0] - 0.5) + abs(raw_probs[1] - 0.5)
corrected_error = abs(corrected_probs[0] - 0.5) + abs(corrected_probs[1] - 0.5)
improvement = (raw_error - corrected_error) / raw_error * 100
print(f" Error reduction: {improvement:.1f}%")
except ImportError:
print("Error mitigation requires advanced Qiskit components")
demonstrate_error_mitigation()
Performance Optimization¶
Execution Time Analysis¶
def qiskit_performance_analysis():
"""Analyze Qiskit backend performance characteristics."""
import time
# Test different simulators
simulators = [
('qasm_simulator', 'Basic QASM simulator'),
('statevector_simulator', 'Statevector simulator'),
]
# Circuit complexity levels
complexities = [
(2, 1, "Simple 2-qubit, 1 layer"),
(4, 2, "Medium 4-qubit, 2 layers"),
(6, 3, "Complex 6-qubit, 3 layers"),
]
results = {}
print("Qiskit Performance Analysis")
print("=" * 30)
for sim_name, sim_desc in simulators:
print(f"\nTesting {sim_name} ({sim_desc}):")
results[sim_name] = {}
try:
for n_qubits, n_layers, desc in complexities:
# Create test circuit
backend = sqx.QiskitBackend(
backend_name=sim_name,
shots=1000,
optimization_level=2
)
circuit = backend.create_circuit(n_qubits)
# Build parameterized circuit
params = np.random.random(n_qubits * n_layers * 2) * 2 * np.pi
param_idx = 0
for layer in range(n_layers):
# Rotation layer
for qubit in range(n_qubits):
circuit.ry(params[param_idx], qubit)
param_idx += 1
circuit.rz(params[param_idx], qubit)
param_idx += 1
# Entangling layer
for qubit in range(n_qubits - 1):
circuit.cx(qubit, qubit + 1)
circuit.measure_all()
# Time execution
start_time = time.time()
result = backend.run(circuit, shots=1000)
execution_time = time.time() - start_time
results[sim_name][(n_qubits, n_layers)] = {
'time': execution_time,
'counts': len(result.get_counts())
}
print(f" {desc}: {execution_time:.3f}s "
f"({len(result.get_counts())} unique outcomes)")
except Exception as e:
print(f" Error with {sim_name}: {e}")
# Shot count vs accuracy analysis
print(f"\nShot Count vs Accuracy Analysis:")
backend = sqx.QiskitBackend(backend_name='qasm_simulator')
# Bell state circuit
circuit = backend.create_circuit(2)
circuit.h(0)
circuit.cx(0, 1)
circuit.measure_all()
shot_counts = [100, 500, 1000, 2000, 5000]
theoretical_prob = 0.5 # For Bell state |00⟩ probability
for shots in shot_counts:
start_time = time.time()
result = backend.run(circuit, shots=shots)
exec_time = time.time() - start_time
counts = result.get_counts()
prob_00 = counts.get('00', 0) / shots
error = abs(prob_00 - theoretical_prob)
print(f" {shots:4d} shots: P(00)={prob_00:.3f}, "
f"Error={error:.3f}, Time={exec_time:.3f}s")
# Optimization level impact
print(f"\nOptimization Level Impact:")
# Complex circuit for optimization testing
test_backend = sqx.QiskitBackend(backend_name='qasm_simulator')
complex_circuit = test_backend.create_circuit(4)
# Create circuit that can be optimized
for i in range(4):
complex_circuit.h(i)
complex_circuit.x(i) # These X gates after H can be optimized
complex_circuit.h(i) # H-X-H = Z-H can be optimized
for i in range(3):
complex_circuit.cx(i, i + 1)
complex_circuit.measure_all()
for opt_level in range(4):
opt_backend = sqx.QiskitBackend(
backend_name='qasm_simulator',
optimization_level=opt_level,
shots=1000
)
start_time = time.time()
result = opt_backend.run(complex_circuit, shots=1000)
exec_time = time.time() - start_time
print(f" Opt level {opt_level}: {exec_time:.3f}s")
qiskit_performance_analysis()
Integration Examples¶
Quantum Machine Learning with Qiskit¶
def qiskit_quantum_ml_example():
"""Comprehensive QML example using Qiskit backend."""
from sklearn.datasets import make_classification
from sklearn.model_selection import train_test_split
from sklearn.preprocessing import StandardScaler
from sklearn.metrics import accuracy_score
print("Quantum Machine Learning with Qiskit")
print("=" * 38)
# Generate dataset
X, y = make_classification(
n_samples=100,
n_features=4,
n_classes=2,
n_redundant=0,
random_state=42
)
# Preprocess data
scaler = StandardScaler()
X_scaled = scaler.fit_transform(X)
X_train, X_test, y_train, y_test = train_test_split(
X_scaled, y, test_size=0.3, random_state=42
)
print(f"Dataset: {len(X)} samples, {X.shape[1]} features, 2 classes")
print(f"Training: {len(X_train)}, Testing: {len(X_test)}")
# Create Quantum SVM using Qiskit backend
qsvm = sqx.QuantumSVM(
backend='qiskit',
feature_map='ZFeatureMap',
num_features=4,
shots=1024
)
# Train quantum SVM
print("\nTraining Quantum SVM with Qiskit backend...")
qsvm.fit(X_train, y_train)
# Make predictions
train_pred = qsvm.predict(X_train)
test_pred = qsvm.predict(X_test)
train_acc = accuracy_score(y_train, train_pred)
test_acc = accuracy_score(y_test, test_pred)
print(f"Training Accuracy: {train_acc:.3f}")
print(f"Test Accuracy: {test_acc:.3f}")
# Compare with different Qiskit simulators
simulators = ['qasm_simulator', 'statevector_simulator']
print(f"\nComparing Qiskit simulators:")
for sim in simulators:
try:
sim_qsvm = sqx.QuantumSVM(
backend=sqx.QiskitBackend(backend_name=sim),
feature_map='ZFeatureMap',
num_features=4
)
sim_qsvm.fit(X_train, y_train)
sim_pred = sim_qsvm.predict(X_test)
sim_acc = accuracy_score(y_test, sim_pred)
print(f" {sim}: {sim_acc:.3f}")
except Exception as e:
print(f" {sim}: Error - {e}")
# Feature map comparison
print(f"\nFeature map comparison:")
feature_maps = ['ZFeatureMap', 'ZZFeatureMap', 'PauliFeatureMap']
for fm in feature_maps:
try:
fm_qsvm = sqx.QuantumSVM(
backend='qiskit',
feature_map=fm,
num_features=4
)
fm_qsvm.fit(X_train, y_train)
fm_pred = fm_qsvm.predict(X_test)
fm_acc = accuracy_score(y_test, fm_pred)
print(f" {fm}: {fm_acc:.3f}")
except Exception as e:
print(f" {fm}: Error - {e}")
qiskit_quantum_ml_example()
Troubleshooting¶
Common Issues¶
1. IBM Quantum Authentication¶
# Fix authentication issues
from qiskit_ibm_runtime import QiskitRuntimeService
# Check saved accounts
saved_accounts = QiskitRuntimeService.saved_accounts()
print("Saved accounts:", saved_accounts)
# Re-save credentials if needed
QiskitRuntimeService.save_account(
channel="ibm_quantum",
token="YOUR_TOKEN",
overwrite=True
)
2. Backend Availability¶
# Check backend status
def check_backend_status():
try:
service = QiskitRuntimeService()
backends = service.backends()
for backend in backends:
status = backend.status()
print(f"{backend.name}: "
f"operational={status.operational}, "
f"pending_jobs={status.pending_jobs}")
except Exception as e:
print(f"Cannot check backends: {e}")
check_backend_status()
3. Memory Issues¶
# Optimize for large circuits
backend = sqx.QiskitBackend(
backend_name='qasm_simulator',
max_parallel_threads=1, # Reduce memory usage
shots=1000,
optimization_level=3 # More optimization
)
Performance Tips¶
- Use appropriate simulators:
statevector_simulator
for small circuits,qasm_simulator
for general use - Optimize circuits: Use
optimization_level=3
for hardware execution - Manage shots: Balance accuracy vs execution time
- Batch jobs: Submit multiple circuits together when possible
- Monitor queue: Check IBM Quantum queue status before submission
Best Practices¶
Code Organization¶
# qiskit_helpers.py
class QiskitHelpers:
@staticmethod
def create_efficient_backend(n_qubits, use_hardware=False):
if use_hardware:
return sqx.QiskitBackend(
backend_name='least_busy',
optimization_level=3,
shots=1024
)
else:
simulator = 'statevector_simulator' if n_qubits <= 10 else 'qasm_simulator'
return sqx.QiskitBackend(
backend_name=simulator,
optimization_level=2,
shots=1000
)
@staticmethod
def submit_with_retry(backend, circuit, max_retries=3):
for attempt in range(max_retries):
try:
return backend.run(circuit)
except Exception as e:
if attempt == max_retries - 1:
raise e
print(f"Attempt {attempt + 1} failed, retrying...")
time.sleep(2 ** attempt) # Exponential backoff
Error Handling¶
def robust_qiskit_execution(circuit, backend_name='qasm_simulator'):
"""Execute circuit with comprehensive error handling."""
try:
backend = sqx.QiskitBackend(backend_name=backend_name)
result = backend.run(circuit, shots=1000)
return result
except Exception as e:
print(f"Execution failed with {backend_name}: {e}")
# Fallback to basic simulator
if backend_name != 'qasm_simulator':
print("Falling back to qasm_simulator...")
return robust_qiskit_execution(circuit, 'qasm_simulator')
else:
raise e
Resources¶
Documentation¶
- Qiskit Documentation: https://qiskit.org/documentation/
- IBM Quantum: https://quantum-computing.ibm.com/
- Qiskit Textbook: https://qiskit.org/textbook/
Hardware Access¶
- IBM Quantum Network: Apply for access to premium quantum systems
- Qiskit Runtime: Optimized quantum program execution
- IBM Quantum Lab: Cloud-based development environment
Qiskit's integration with SuperQuantX provides seamless access to IBM's quantum ecosystem, from high-performance simulators to cutting-edge quantum processors. The unified API makes it easy to develop quantum applications while leveraging IBM's quantum expertise.
Optimization
For best performance on IBM hardware, use optimization_level=3
and minimize circuit depth. Consider using Qiskit Runtime for reduced latency.
Queue Times
Real IBM quantum hardware may have significant queue times. Check device status and consider using simulators for development.
Hardware Access
IBM Quantum Network membership provides access to advanced quantum systems and priority queue access.