# ===== app.py ===== # Full interactive H2 Quantum Simulator + 3D molecule (modern Qiskit) # --- Standard math --- import numpy as np # --- Graphing & UI --- import plotly.graph_objects as go import gradio as gr # --- Qiskit (modern second_q API) --- from qiskit_nature.second_q.drivers import PySCFDriver from qiskit_nature.second_q.problems import ElectronicStructureProblem from qiskit_nature.second_q.converters import QubitConverter from qiskit_nature.second_q.mappers 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 # ---------------------------- # Compute H2 ground state energy using VQE # ---------------------------- def h2_ground_state_energy(bond_length): bond_length = float(bond_length) 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 # ---------------------------- # Create 3D molecule plot # ---------------------------- 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 # ---------------------------- # Generate energy curve over bond lengths # ---------------------------- def h2_energy_curve(dummy): bond_lengths = np.linspace(0.4, 2.0, 10) energies = [h2_ground_state_energy(bl) for bl in bond_lengths] 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 # ---------------------------- # Full interface: single bond length + 3D molecule # ---------------------------- 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 # --- Gradio interfaces --- 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 simulation of H2. Enter bond length to compute energy." ) 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." ) demo = gr.TabbedInterface( [iface, energy_curve_iface], ["Single Bond Length", "Energy Curve"] ) # Launch app demo.launch()

app.py

@@ -1,28 +1,31 @@
-# app.py
-# Full interactive H2 Quantum Simulator + 3D molecule
-
-# Install dependencies: gradio, plotly, qiskit, qiskit-nature, matplotlib
+# ===== app.py =====
+# Full interactive H2 Quantum Simulator + 3D molecule (modern Qiskit)
 
+# --- Standard math ---
 import numpy as np
+
+# --- Graphing & UI ---
 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
+# --- Qiskit (modern second_q API) ---
+from qiskit_nature.second_q.drivers import PySCFDriver
+from qiskit_nature.second_q.problems import ElectronicStructureProblem
+from qiskit_nature.second_q.converters import QubitConverter
+from qiskit_nature.second_q.mappers 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 -----
+# ----------------------------
+# Compute H2 ground state energy 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)
     
@@ -49,7 +52,9 @@ def h2_ground_state_energy(bond_length):
     energy = result.eigenvalue.real
     return energy
 
-# ----- Function to create 3D molecule plot using plotly -----
+# ----------------------------
+# Create 3D molecule plot
+# ----------------------------
 def h2_3d_plot(bond_length):
     bond_length = float(bond_length)
     
@@ -59,9 +64,17 @@ def h2_3d_plot(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')))
+    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.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',
@@ -69,18 +82,20 @@ def h2_3d_plot(bond_length):
         zaxis_title='Z Å',
         aspectmode='data'
     ))
+    
     return fig
 
-# ----- Function to generate energy curve over range of bond lengths -----
+# ----------------------------
+# Generate energy curve over 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)
+    energies = [h2_ground_state_energy(bl) for bl in bond_lengths]
     
     fig = go.Figure()
-    fig.add_trace(go.Scatter(x=bond_lengths, y=energies, mode='lines+markers'))
+    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)",
@@ -88,23 +103,24 @@ def h2_energy_curve(dummy):
     )
     return fig
 
-# ----- Combine all into one interface -----
+# ----------------------------
+# Full interface: single bond length + 3D molecule
+# ----------------------------
 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
 
+# --- Gradio interfaces ---
 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."
+    description="Interactive 3D molecule + VQE simulation of H2. Enter bond length to compute energy."
 )
 
-# Add separate energy curve tab
 energy_curve_iface = gr.Interface(
     fn=h2_energy_curve,
     inputs=gr.Textbox(label="Dummy Input", placeholder="Press submit"),
@@ -113,6 +129,10 @@ energy_curve_iface = gr.Interface(
     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)
+demo = gr.TabbedInterface(
+    [iface, energy_curve_iface],
+    ["Single Bond Length", "Energy Curve"]
+)
+
+# Launch app
+demo.launch()