报告题目 (Title)：Enhancing Quantum System Simulation with Clifford-Based Hybrid Quantum Algorithm（应用基于Clifford代数的混合量子算法增强量子系统模拟）

报告人 (Speaker)：孙嘉策（美国加州理工学院）

报告时间 (Time)：2024年4月17日(周三) 9:00

报告地点 (Place)：在线报告，腾讯会议室：958-114-931

https://meeting.tencent.com/dm/WkbWTbDWpWNk 

邀请人 (Inviter)：李永乐 副教授

主办部门：理学院物理系

摘要(Abstract)：

Although simulating quantum systems is recognized as one of the most practical applications of quantum computing, attaining high accuracy with shallow quantum circuits remains a formidable challenge, particularly in the noisy intermediate-scale quantum (NISQ) era. In recent years, hybrid quantum variational algorithms leveraging the strengths of both classical and quantum computing have emerged as a promising solution to enhance accuracy while maintaining lower circuit depths. We present a suite of Clifford-based hybrid quantum variational algorithms designed for various quantum systems. (1) For weakly entangled chemical systems, we introduced a protocol to identify near-optimal Clifford Hamiltonian transformations for ground-state problems. This protocol, efficiently executable on classical computers, is compatible with any hardware-efficient ansatz. Our demonstrations on a quantum hardware emulator show its efficacy, achieving chemical accuracy in systems up to 12 qubits using fewer than 30 two-qubit gates. (2) For strongly entangled physical systems, we have developed a linear-scaled algorithm that determines the exact stabilizer ground state for special types of Hamiltonians. These exact stabilizer ground states can not only be used as effective initial states for variational quantum eigenvalue optimization processes but also serve as cornerstones of more advanced quantum ground state ansatz.