物理学院学术报告（第64期）

报告题目：Quantum Simulations on a Programmable NISQ-era Quantum Computer

报告专家：陈天骐博士    新加坡国立大学

报告时间：2024年09月12日（周四）10:00

报告地点：理6栋302      邀请人：张旦波

报告内容：

The current NISQ-era has seen so much progress in using programmable digital quantum computers for the simulation of novel physics phenomena in quantum many-body systems [R. Barends et. al., Nat. Comm. (2015); Y. Salathe et. al., Phys. Rev. X (2015); X. Zhang et. al., Nature (2022); A.J. Daley et. al., Nature (2022)]. To this end, these hardware simulations on NISQ devices may serve as a certain kind of unique testbed for exotic phases of matter for a variety of systems. However, finding an appropriate algorithm or framework to properly implement them is not easy. That said, we shall ask ourselves: what is the practical advantage of using a quantum processor for possible prediction/explanation of simulating nontrivial many-body physics? In this talk, I will discuss some of our recent progress along this direction. I will first talk about how we embed a non-unitary operator into a unitary one using an additional ancilla qubit, and how to implement such a unitary operator with quantum circuit recompilation approach using a tensor network-based optimization algorithm. We then apply this approach to two topics: the preparation of the Affleck-Lieb-Kennedy-Tasaki (AKLT) state, and realization of the many-body version of the non-Hermitian skin effect (NHSE), dubbed ‘edge Fermi skin’ and ‘bulk Fermi skin’ on a noisy IBM quantum processor. We also show that this works for simulating Hermitian systems, where we focused on a special kind of large-period discrete time crystals (DTCs), as well as for directly probing quantum metric tensor for topological systems.

专家简介：

Dr. Chen Tianqi has been a post-doctoral research fellow in Prof. Gong Jiangbin’s group at National University of Singapore (NUS) since 2023, in shared collaboration with Prof. Lee Ching Hua (NUS). Previously, he worked at Nanyang Technological University with Prof. Yang Bo. From 2017 to 2021, he was with the Science, Mathematics and Technology (SMT) cluster at the Singapore University of Technology and Design (SUTD) in the group of Prof. Dario Poletti, where he obtained his PhD in 2021. Before that, Tianqi was a research assistant in the group of Prof. Tim Byrnes at NYU Shanghai in 2016. He spent his undergraduate time at Fudan University. Tianqi’s current research interests include quantum computing and practical quantum algorithms for condensed matter physics, quantum many-body physics simulation with tensor network states, non-equilibrium quantum many-body systems, and emergent behavior in complex biological systems.