Programme

I.12 -- Invited, VCTP-51

Date: Thursday, 6 August 2026

Time: 14:00 - 14:40

Development of quantum computing algorithms for quantum molecular simulations

Tran Nguyen Lan

Unversity of Science, VNUHCM

Quantum computing holds transformative promise for molecular simulations, yet practical deployment on near-term devices remains challenging. In this talk, I will survey the current landscape of quantum algorithms for molecular simulation focusing on Variational Quantum Eigensolver (VQE) and Sample-Based Quantum Diagonalization (SQD). I will then present our recent developments in quantum simulation algorithms. First, we tackle the gradient stagnation in ADAPT-VQE through an operator elimination strategy that reduces circuit depth and iteration count while preserving accuracy. Second, we augment ADAPT-VQE with one-body downfolding (OBDF) to capture out-of-active-space dynamical correlations via an effective Hamiltonian, recovering electron correlation missed by standard active-space approaches. Third, we introduce OBDF-SQD, which seamlessly integrates OBDF into SQD to achieve superior accuracy over conventional active-space SQD, with no additional circuit overhead. Overall, our results demonstrate that adaptive ansatz construction and effective Hamiltonian techniques offer practical, high-impact pathways toward accurate and efficient near-term quantum molecular simulations.

Presenter: Tran Nguyen Lan