# app.py # Full interactive H2 Quantum Simulator + 3D molecule # Install dependencies: gradio, plotly, qiskit, qiskit-nature, matplotlib import numpy as np import plotly.graph_objects as go import gradio as gr # Qiskit imports from qiskit_nature.drivers import PySCFDriver from qiskit_nature.problems.second_quantization.electronic import ElectronicStructureProblem from qiskit_nature.converters.second_quantization import QubitConverter from qiskit_nature.mappers.second_quantization import JordanWignerMapper from qiskit.algorithms import VQE from qiskit.algorithms.optimizers import COBYLA from qiskit.circuit.library import TwoLocal from qiskit.utils import QuantumInstance from qiskit import Aer # ----- Function to compute ground state energy of H2 using VQE ----- def h2_ground_state_energy(bond_length): bond_length = float(bond_length) # Define H2 molecule driver = PySCFDriver(atom=f"H 0 0 0; H 0 0 {bond_length}", basis='sto3g') problem = ElectronicStructureProblem(driver) # Hamiltonian second_q_ops = problem.second_q_ops() main_op = second_q_ops[0] # Map to qubits qubit_converter = QubitConverter(mapper=JordanWignerMapper()) qubit_op = qubit_converter.convert(main_op) # Ansatz & optimizer ansatz = TwoLocal(qubit_op.num_qubits, 'ry', 'cz', reps=2) optimizer = COBYLA(maxiter=100) # Quantum instance backend = Aer.get_backend('statevector_simulator') qi = QuantumInstance(backend) # Run VQE vqe = VQE(ansatz=ansatz, optimizer=optimizer, quantum_instance=qi) result = vqe.compute_minimum_eigenvalue(qubit_op) energy = result.eigenvalue.real return energy # ----- Function to create 3D molecule plot using plotly ----- def h2_3d_plot(bond_length): bond_length = float(bond_length) x = [0, 0] y = [0, 0] z = [0, bond_length] fig = go.Figure() # Atoms fig.add_trace(go.Scatter3d(x=x, y=y, z=z, mode='markers', marker=dict(size=10, color='red'))) # Bond fig.add_trace(go.Scatter3d(x=x, y=y, z=z, mode='lines', line=dict(color='blue', width=5))) fig.update_layout(scene=dict( xaxis_title='X Å', yaxis_title='Y Å', zaxis_title='Z Å', aspectmode='data' )) return fig # ----- Function to generate energy curve over range of bond lengths ----- def h2_energy_curve(dummy): bond_lengths = np.linspace(0.4, 2.0, 10) energies = [] for bl in bond_lengths: energy = h2_ground_state_energy(bl) energies.append(energy) fig = go.Figure() fig.add_trace(go.Scatter(x=bond_lengths, y=energies, mode='lines+markers')) fig.update_layout( title="H2 Ground State Energy vs Bond Length", xaxis_title="Bond Length (Å)", yaxis_title="Energy (Hartree)" ) return fig # ----- Combine all into one interface ----- def full_interface(bond_length): bond_length_float = float(bond_length) energy = h2_ground_state_energy(bond_length_float) mol_fig = h2_3d_plot(bond_length_float) return f"Ground state energy: {energy:.6f} Hartree", mol_fig iface = gr.Interface( fn=full_interface, inputs=gr.Textbox(label="Bond Length Å", placeholder="Enter e.g., 0.74"), outputs=[gr.Textbox(label="Ground State Energy"), gr.Plot(label="3D Molecule")], title="H2 Quantum Simulator", description="Interactive 3D molecule + VQE Quantum simulation of H2. Enter bond length to compute energy and see molecule." ) # Add separate energy curve tab energy_curve_iface = gr.Interface( fn=h2_energy_curve, inputs=gr.Textbox(label="Dummy Input", placeholder="Press submit"), outputs=gr.Plot(label="Energy Curve"), title="H2 Energy Curve", description="Shows ground state energy of H2 over bond lengths 0.4–2.0 Å." ) # Launch all interfaces as Tabs demo = gr.TabbedInterface([iface, energy_curve_iface], ["Single Bond Length", "Energy Curve"]) demo.launch(share=True)

app.py

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+# app.py
+# Full interactive H2 Quantum Simulator + 3D molecule
+
+# Install dependencies: gradio, plotly, qiskit, qiskit-nature, matplotlib
+
+import numpy as np
+import plotly.graph_objects as go
+import gradio as gr
+
+# Qiskit imports
+from qiskit_nature.drivers import PySCFDriver
+from qiskit_nature.problems.second_quantization.electronic import ElectronicStructureProblem
+from qiskit_nature.converters.second_quantization import QubitConverter
+from qiskit_nature.mappers.second_quantization import JordanWignerMapper
+from qiskit.algorithms import VQE
+from qiskit.algorithms.optimizers import COBYLA
+from qiskit.circuit.library import TwoLocal
+from qiskit.utils import QuantumInstance
+from qiskit import Aer
+
+# ----- Function to compute ground state energy of H2 using VQE -----
+def h2_ground_state_energy(bond_length):
+    bond_length = float(bond_length)
+    
+    # Define H2 molecule
+    driver = PySCFDriver(atom=f"H 0 0 0; H 0 0 {bond_length}", basis='sto3g')
+    problem = ElectronicStructureProblem(driver)
+    
+    # Hamiltonian
+    second_q_ops = problem.second_q_ops()
+    main_op = second_q_ops[0]
+    
+    # Map to qubits
+    qubit_converter = QubitConverter(mapper=JordanWignerMapper())
+    qubit_op = qubit_converter.convert(main_op)
+    
+    # Ansatz & optimizer
+    ansatz = TwoLocal(qubit_op.num_qubits, 'ry', 'cz', reps=2)
+    optimizer = COBYLA(maxiter=100)
+    
+    # Quantum instance
+    backend = Aer.get_backend('statevector_simulator')
+    qi = QuantumInstance(backend)
+    
+    # Run VQE
+    vqe = VQE(ansatz=ansatz, optimizer=optimizer, quantum_instance=qi)
+    result = vqe.compute_minimum_eigenvalue(qubit_op)
+    
+    energy = result.eigenvalue.real
+    return energy
+
+# ----- Function to create 3D molecule plot using plotly -----
+def h2_3d_plot(bond_length):
+    bond_length = float(bond_length)
+    
+    x = [0, 0]
+    y = [0, 0]
+    z = [0, bond_length]
+    
+    fig = go.Figure()
+    # Atoms
+    fig.add_trace(go.Scatter3d(x=x, y=y, z=z, mode='markers', marker=dict(size=10, color='red')))
+    # Bond
+    fig.add_trace(go.Scatter3d(x=x, y=y, z=z, mode='lines', line=dict(color='blue', width=5)))
+    
+    fig.update_layout(scene=dict(
+        xaxis_title='X Å',
+        yaxis_title='Y Å',
+        zaxis_title='Z Å',
+        aspectmode='data'
+    ))
+    return fig
+
+# ----- Function to generate energy curve over range of bond lengths -----
+def h2_energy_curve(dummy):
+    bond_lengths = np.linspace(0.4, 2.0, 10)
+    energies = []
+    for bl in bond_lengths:
+        energy = h2_ground_state_energy(bl)
+        energies.append(energy)
+    
+    fig = go.Figure()
+    fig.add_trace(go.Scatter(x=bond_lengths, y=energies, mode='lines+markers'))
+    fig.update_layout(
+        title="H2 Ground State Energy vs Bond Length",
+        xaxis_title="Bond Length (Å)",
+        yaxis_title="Energy (Hartree)"
+    )
+    return fig
+
+# ----- Combine all into one interface -----
+def full_interface(bond_length):
+    bond_length_float = float(bond_length)
+    energy = h2_ground_state_energy(bond_length_float)
+    mol_fig = h2_3d_plot(bond_length_float)
+    
+    return f"Ground state energy: {energy:.6f} Hartree", mol_fig
+
+iface = gr.Interface(
+    fn=full_interface,
+    inputs=gr.Textbox(label="Bond Length Å", placeholder="Enter e.g., 0.74"),
+    outputs=[gr.Textbox(label="Ground State Energy"), gr.Plot(label="3D Molecule")],
+    title="H2 Quantum Simulator",
+    description="Interactive 3D molecule + VQE Quantum simulation of H2. Enter bond length to compute energy and see molecule."
+)
+
+# Add separate energy curve tab
+energy_curve_iface = gr.Interface(
+    fn=h2_energy_curve,
+    inputs=gr.Textbox(label="Dummy Input", placeholder="Press submit"),
+    outputs=gr.Plot(label="Energy Curve"),
+    title="H2 Energy Curve",
+    description="Shows ground state energy of H2 over bond lengths 0.4–2.0 Å."
+)
+
+# Launch all interfaces as Tabs
+demo = gr.TabbedInterface([iface, energy_curve_iface], ["Single Bond Length", "Energy Curve"])
+demo.launch(share=True)