ruqu-algorithms -- Quantum Algorithm Implementations

High-level quantum algorithms built on the ruqu-core simulation engine:

• VQE (Variational Quantum Eigensolver): Find ground-state energies of molecular Hamiltonians using a classical-quantum hybrid loop with hardware-efficient ansatz and parameter-shift gradient descent.

• Grover's Search: Quadratic speedup for unstructured search over N items, using amplitude amplification with direct state-vector oracle access.

• QAOA (Quantum Approximate Optimization Algorithm): Approximate solutions to combinatorial optimization problems (MaxCut) via parameterized phase-separation and mixing layers.

• Surface Code: Distance-3 surface code error correction simulation with stabilizer measurement cycles, noise injection, and syndrome decoding.

Quick Start

use ruqu_algorithms::{VqeConfig, run_vqe, vqe::h2_hamiltonian};

let config = VqeConfig {
    hamiltonian: h2_hamiltonian(),
    num_qubits: 2,
    ansatz_depth: 2,
    max_iterations: 100,
    convergence_threshold: 1e-6,
    learning_rate: 0.1,
    seed: Some(42),
};
let result = run_vqe(&config).expect("VQE failed");
println!("Ground state energy: {:.6}", result.optimal_energy);