# ===== Ultimate Quantum Chemistry Platform (Starter) ===== # Python 3.11 + Qiskit stable + Gradio + Plotly import numpy as np import plotly.graph_objects as go import gradio as gr from qiskit_nature.second_q.drivers import PySCFDriver from qiskit_nature.second_q.problems import ElectronicStructureProblem from qiskit_nature.second_q.mappers import JordanWignerMapper from qiskit.algorithms.minimum_eigensolvers import VQE from qiskit.algorithms.optimizers import COBYLA from qiskit.circuit.library import TwoLocal from qiskit.primitives import Estimator # stable Qiskit 1.12 # ---------------------------- # Molecules Library # ---------------------------- molecules = { "H2": {"atoms": ["H", "H"], "coords": [(0,0,0), (0,0,0.74)]}, "LiH": {"atoms": ["Li", "H"], "coords": [(0,0,0), (0,0,1.6)]}, "BeH2": {"atoms": ["Be","H","H"], "coords": [(0,0,0), (0,0,1.3), (0,0,-1.3)]} } # ---------------------------- # Quantum ground state energy # ---------------------------- def compute_ground_state_energy(mol_name, bond_length): bond_length = float(bond_length) if mol_name == "H2": atom_str = f"H 0 0 0; H 0 0 {bond_length}" elif mol_name == "LiH": atom_str = f"Li 0 0 0; H 0 0 {bond_length}" elif mol_name == "BeH2": # symmetrically along z-axis atom_str = f"Be 0 0 0; H 0 0 {bond_length}; H 0 0 {-bond_length}" else: raise ValueError("Molecule not supported") driver = PySCFDriver(atom=atom_str, basis="sto3g") problem = ElectronicStructureProblem(driver) hamiltonian = problem.second_q_ops()[0] qubit_op = JordanWignerMapper().map(hamiltonian) ansatz = TwoLocal(qubit_op.num_qubits, "ry", "cz", reps=2) vqe = VQE(estimator=Estimator(), ansatz=ansatz, optimizer=COBYLA(maxiter=80)) result = vqe.compute_minimum_eigenvalue(qubit_op) energy = result.eigenvalue.real return energy # ---------------------------- # 3D molecule plot # ---------------------------- def molecule_3d_plot(mol_name, bond_length): bond_length = float(bond_length) if mol_name == "H2": coords = [(0,0,0),(0,0,bond_length)] elif mol_name == "LiH": coords = [(0,0,0),(0,0,bond_length)] elif mol_name == "BeH2": coords = [(0,0,0),(0,0,bond_length),(0,0,-bond_length)] else: coords = [] x, y, z = zip(*coords) fig = go.Figure() fig.add_trace(go.Scatter3d( x=x, y=y, z=z, mode="markers", marker=dict(size=8, color="red") )) fig.add_trace(go.Scatter3d( x=x, y=y, z=z, mode="lines", line=dict(color="blue", width=5) )) fig.update_layout(scene=dict(aspectmode="data")) return fig # ---------------------------- # Energy curve precompute (for 0.4 - 2.0 Å) # ---------------------------- bond_grid = np.linspace(0.4, 2.0, 12) energy_curves = {} for mol in molecules: energy_curves[mol] = [compute_ground_state_energy(mol, bl) for bl in bond_grid] # ---------------------------- # Update UI # ---------------------------- def update_ui(mol_name, bond_length): bond_length = float(bond_length) energy = compute_ground_state_energy(mol_name, bond_length) mol_fig = molecule_3d_plot(mol_name, bond_length) curve_fig = go.Figure() curve_fig.add_trace(go.Scatter( x=bond_grid, y=energy_curves[mol_name], mode="lines+markers", name="Energy Curve" )) curve_fig.add_trace(go.Scatter( x=[bond_length], y=[energy], mode="markers", marker=dict(size=12, color="green"), name="Current Energy" )) min_idx = int(np.argmin(energy_curves[mol_name])) curve_fig.add_trace(go.Scatter( x=[bond_grid[min_idx]], y=[energy_curves[mol_name][min_idx]], mode="markers", marker=dict(size=14, color="orange"), name="Equilibrium" )) curve_fig.update_layout( xaxis_title="Bond Length (Å)", yaxis_title="Energy (Hartree)" ) text = f"Ground state energy: {energy:.6f} Hartree\nEquilibrium bond length ≈ {bond_grid[min_idx]:.2f} Å" return text, mol_fig, curve_fig # ---------------------------- # Gradio App # ---------------------------- with gr.Blocks() as demo: gr.Markdown("# 🧬 Ultimate Quantum Chemistry Platform") mol_dropdown = gr.Dropdown(list(molecules.keys()), value="H2", label="Select Molecule") bond_slider = gr.Slider(0.4, 2.0, value=0.74, step=0.01, label="Bond Length (Å)") energy_box = gr.Textbox(label="Energy", lines=2) mol_plot = gr.Plot(label="3D Molecule") curve_plot = gr.Plot(label="Energy Curve") mol_dropdown.change(update_ui, [mol_dropdown, bond_slider], [energy_box, mol_plot, curve_plot]) bond_slider.change(update_ui, [mol_dropdown, bond_slider], [energy_box, mol_plot, curve_plot]) demo.launch()

app.py

@@ -1,172 +1,141 @@
-# ===== app.py =====
-# Full interactive H2 Quantum Simulator + 3D molecule (modern Qiskit)
-
-# --- Standard math ---
+# ===== Ultimate Quantum Chemistry Platform (Starter) =====
+# Python 3.11 + Qiskit stable + Gradio + Plotly
 import numpy as np
-
-# --- Graphing & UI ---
 import plotly.graph_objects as go
 import gradio as gr
 
-# --- Qiskit Nature (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.mappers import JordanWignerMapper
-
-# --- Qiskit Algorithms (modern primitives API) ---
-from qiskit_algorithms.minimum_eigensolvers import VQE
-from qiskit_algorithms.optimizers import COBYLA
+from qiskit.algorithms.minimum_eigensolvers import VQE
+from qiskit.algorithms.optimizers import COBYLA
 from qiskit.circuit.library import TwoLocal
-from qiskit.primitives import Estimator
+from qiskit.primitives import Estimator  # stable Qiskit 1.12
 
+# ----------------------------
+# Molecules Library
+# ----------------------------
+molecules = {
+    "H2": {"atoms": ["H", "H"], "coords": [(0,0,0), (0,0,0.74)]},
+    "LiH": {"atoms": ["Li", "H"], "coords": [(0,0,0), (0,0,1.6)]},
+    "BeH2": {"atoms": ["Be","H","H"], "coords": [(0,0,0), (0,0,1.3), (0,0,-1.3)]}
+}
 
 # ----------------------------
-# Compute H2 ground state energy using VQE
+# Quantum ground state energy
 # ----------------------------
-def h2_ground_state_energy(bond_length):
+def compute_ground_state_energy(mol_name, bond_length):
     bond_length = float(bond_length)
-
-    # Electronic structure driver
-    driver = PySCFDriver(
-        atom=f"H 0 0 0; H 0 0 {bond_length}",
-        basis="sto3g"
-    )
-
+    
+    if mol_name == "H2":
+        atom_str = f"H 0 0 0; H 0 0 {bond_length}"
+    elif mol_name == "LiH":
+        atom_str = f"Li 0 0 0; H 0 0 {bond_length}"
+    elif mol_name == "BeH2":
+        # symmetrically along z-axis
+        atom_str = f"Be 0 0 0; H 0 0 {bond_length}; H 0 0 {-bond_length}"
+    else:
+        raise ValueError("Molecule not supported")
+    
+    driver = PySCFDriver(atom=atom_str, basis="sto3g")
     problem = ElectronicStructureProblem(driver)
-
-    # Get second-quantized Hamiltonian
-    second_q_ops = problem.second_q_ops()
-    hamiltonian = second_q_ops[0]
-
-    # Map fermions -> qubits
-    mapper = JordanWignerMapper()
-    qubit_op = mapper.map(hamiltonian)
-
-    # Ansatz
-    ansatz = TwoLocal(
-        num_qubits=qubit_op.num_qubits,
-        rotation_blocks="ry",
-        entanglement_blocks="cz",
-        reps=2
-    )
-
-    # Optimizer + estimator
-    optimizer = COBYLA(maxiter=100)
-    estimator = Estimator()
-
-    # VQE
-    vqe = VQE(
-        estimator=estimator,
-        ansatz=ansatz,
-        optimizer=optimizer
-    )
-
+    hamiltonian = problem.second_q_ops()[0]
+    
+    qubit_op = JordanWignerMapper().map(hamiltonian)
+    
+    ansatz = TwoLocal(qubit_op.num_qubits, "ry", "cz", reps=2)
+    vqe = VQE(estimator=Estimator(), ansatz=ansatz, optimizer=COBYLA(maxiter=80))
+    
     result = vqe.compute_minimum_eigenvalue(qubit_op)
-    return result.eigenvalue.real
-
+    energy = result.eigenvalue.real
+    return energy
 
 # ----------------------------
-# Create 3D molecule plot
+# 3D molecule plot
 # ----------------------------
-def h2_3d_plot(bond_length):
+def molecule_3d_plot(mol_name, bond_length):
     bond_length = float(bond_length)
-
-    x = [0, 0]
-    y = [0, 0]
-    z = [0, bond_length]
-
+    if mol_name == "H2":
+        coords = [(0,0,0),(0,0,bond_length)]
+    elif mol_name == "LiH":
+        coords = [(0,0,0),(0,0,bond_length)]
+    elif mol_name == "BeH2":
+        coords = [(0,0,0),(0,0,bond_length),(0,0,-bond_length)]
+    else:
+        coords = []
+    
+    x, y, z = zip(*coords)
     fig = go.Figure()
-
-    # Atoms
     fig.add_trace(go.Scatter3d(
         x=x, y=y, z=z,
         mode="markers",
-        marker=dict(size=10, color="red"),
-        name="Hydrogen atoms"
+        marker=dict(size=8, color="red")
     ))
-
-    # Bond
     fig.add_trace(go.Scatter3d(
         x=x, y=y, z=z,
         mode="lines",
-        line=dict(color="blue", width=5),
-        name="Bond"
+        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"
-        ),
-        margin=dict(l=0, r=0, b=0, t=0)
-    )
-
+    fig.update_layout(scene=dict(aspectmode="data"))
     return fig
 
-
 # ----------------------------
-# Generate energy curve over bond lengths
+# Energy curve precompute (for 0.4 - 2.0 Å)
 # ----------------------------
-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]
+bond_grid = np.linspace(0.4, 2.0, 12)
+energy_curves = {}
+for mol in molecules:
+    energy_curves[mol] = [compute_ground_state_energy(mol, bl) for bl in bond_grid]
 
-    fig = go.Figure()
-    fig.add_trace(go.Scatter(
-        x=bond_lengths,
-        y=energies,
-        mode="lines+markers"
+# ----------------------------
+# Update UI
+# ----------------------------
+def update_ui(mol_name, bond_length):
+    bond_length = float(bond_length)
+    energy = compute_ground_state_energy(mol_name, bond_length)
+    mol_fig = molecule_3d_plot(mol_name, bond_length)
+    
+    curve_fig = go.Figure()
+    curve_fig.add_trace(go.Scatter(
+        x=bond_grid, y=energy_curves[mol_name],
+        mode="lines+markers",
+        name="Energy Curve"
     ))
-
-    fig.update_layout(
-        title="H₂ Ground State Energy vs Bond Length",
+    curve_fig.add_trace(go.Scatter(
+        x=[bond_length], y=[energy],
+        mode="markers",
+        marker=dict(size=12, color="green"),
+        name="Current Energy"
+    ))
+    min_idx = int(np.argmin(energy_curves[mol_name]))
+    curve_fig.add_trace(go.Scatter(
+        x=[bond_grid[min_idx]], y=[energy_curves[mol_name][min_idx]],
+        mode="markers",
+        marker=dict(size=14, color="orange"),
+        name="Equilibrium"
+    ))
+    curve_fig.update_layout(
         xaxis_title="Bond Length (Å)",
         yaxis_title="Energy (Hartree)"
     )
-
-    return fig
-
+    
+    text = f"Ground state energy: {energy:.6f} Hartree\nEquilibrium bond length ≈ {bond_grid[min_idx]:.2f} Å"
+    return text, mol_fig, curve_fig
 
 # ----------------------------
-# Full interface: single bond length + 3D molecule
+# Gradio App
 # ----------------------------
-def full_interface(bond_length):
-    bond_length = float(bond_length)
-    energy = h2_ground_state_energy(bond_length)
-    mol_fig = h2_3d_plot(bond_length)
-
-    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 VQE simulation + 3D visualization of the H₂ molecule."
-)
-
-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="Ground state energy of H₂ for bond lengths 0.4–2.0 Å."
-)
-
-demo = gr.TabbedInterface(
-    [iface, energy_curve_iface],
-    ["Single Bond Length", "Energy Curve"]
-)
+with gr.Blocks() as demo:
+    gr.Markdown("# 🧬 Ultimate Quantum Chemistry Platform")
+    
+    mol_dropdown = gr.Dropdown(list(molecules.keys()), value="H2", label="Select Molecule")
+    bond_slider = gr.Slider(0.4, 2.0, value=0.74, step=0.01, label="Bond Length (Å)")
+    
+    energy_box = gr.Textbox(label="Energy", lines=2)
+    mol_plot = gr.Plot(label="3D Molecule")
+    curve_plot = gr.Plot(label="Energy Curve")
+    
+    mol_dropdown.change(update_ui, [mol_dropdown, bond_slider], [energy_box, mol_plot, curve_plot])
+    bond_slider.change(update_ui, [mol_dropdown, bond_slider], [energy_box, mol_plot, curve_plot])
 
-# Launch app
 demo.launch()