Events

Qualifying Exam Full-Stack Optimization of Quantum Chemistry Simulations
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Speaker: Zirui Li

Bio

Location : CoRE 229

Committee: 

Assistant Professor Yipeng Huang

Professor Eddy Z. Zhang

Professor Mario Szegedy

Associate Professor Jingjin Yu

Event Type: Qualifying Exam

Abstract: Simulating the ground state energy of molecular systems remains a central challenge in quantum chemistry and a promising application for quantum computing. Achieving accurate results on near-term quantum hardware requires careful optimization across the full computational stack—from algorithm design to algorithm compilation and hardware execution. In this work, I present two major contributions on compilation and execution, and preview my ongoing work on algorithm design. First, I introduce compiler-level techniques for optimizing the Unitary Coupled Cluster Singles and Doubles (UCCSD) ansatz, a foundational algorithm in quantum chemistry. These techniques reduce CNOT gate counts and circuit depth, significantly mitigating noise and increasing fidelity. Second, I explore quantum circuit cutting as a scalable execution strategy for large quantum circuits that exceed hardware qubit limits. By decomposing a large circuit into smaller, independently executable subcircuits and reconstructing results through classical postprocessing, this approach enables simulations beyond current hardware constraints. I further introduce a novel optimization that leverages the determinism of Clifford subcircuits to reduce experimental overhead during subcircuit tomography and memory requirements during postprocessing. Finally, I provide a preview of my ongoing work on ansatz design, focusing on balancing trainability, expressibility, noise resilience, and accuracy. These preliminary efforts aim to improve the practicality of near-term quantum simulations in quantum chemistry and lay the groundwork for further exploration in full-stack optimization.List of publications:Y. Jin et al., "Tetris: A Compilation Framework for VQA Applications in Quantum Computing," 2024 ACM/IEEE 51st Annual International Symposium on Computer Architecture (ISCA), Buenos Aires, Argentina, 2024, pp. 277-292, doi: 10.1109/ISCA59077.2024.00029.Z. Li et al., "A Case for Quantum Circuit Cutting for NISQ Applications: Impact of topology, determinism, and sparsity" arxiv: 2412.17929

Organization: 

Contact  Assistant Professor Yipeng Huang

https://us05web.zoom.us/j/83821848816?pwd=kTSjEbN8IbEZc687RqLTa8pKYyQajS.1