Abstract:
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)]. Although the current NISQ device naturally hosts the unitary quantum gates, it remains a challenge to implement non-unitary operations on these devices, as the operator itself cannot be decomposed into the fundamental gates on a quantum computer. In this talk, I discuss two of our recent progress to address this issue. I will first talk about how we embed a nonunitary 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, such that the circuit depth is shallow enough for running on the NISQ-era devices. We then apply this approach to two topics. First, we transform a non-unitary projection operator for the generation of the Affleck-Lieb-Kennedy-Tasaki (AKLT) state, and realize it on IBM Q. We show how the accuracy of our implementation can be further improved on the IBM quantum processor with readout error mitigation. For the second part, we provide some of our recent preliminary results on the non-Hermitian skin effect (NHSE) for Su-Schrieffer-Heeger (nH-SSH) model on a noisy IBM quantum processor, and discovered the main signature of the NHSE being the asymmetric spatial propagation and attenuation.
Biography:
Dr. Chen Tianqi has been a post-doctoral research fellow in Professor Bo Yang’s group at Nanyang Technological University (NTU) since 2022, in shared collaboration with Professor Ching Hua Lee from National University of Singapore (NUS). 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 Professor Dario Poletti, where he obtained his PhD in 2021. Before that, Tianqi was a research assistant in the group of Professor Tim Byrnes at NYU Shanghai in 2016. He spent his undergraduate time at Fudan University. Tianqi’s current research interests include quantum computing, quantum many-body physics simulation with tensor network states, nonequilibrium quantum thermodynamics, and emergent behavior in com-plex biological systems. In his leisure time, he enjoys reading, swimming, cooking a hearty meal for loved ones, language, and tennis.
Seminar by the NYU-ECNU Institute of Physics at NYU Shanghai