Stabilizing multiple topological fermions on a quantum computer

• Published in: npj quantum information Vol. 8; no. 1; pp. 1 - 10
• Main Authors: Koh, Jin Ming, Tai, Tommy, Phee, Yong Han, Ng, Wei En, Lee, Ching Hua
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 16.02.2022; Nature Publishing Group; Nature Portfolio
• Subjects: 639/766/119/995; 639/766/483; 639/766/483/2802; 639/766/483/3926; Algorithms; Classical and Quantum Gravitation; Computers; Design; Physics; Physics and Astronomy; Quantum Computing; Quantum Field Theories; Quantum Information Technology; Quantum Physics; Relativity Theory; Spintronics; String Theory; Symmetry
• ISSN: 2056-6387; 2056-6387
• DOI: 10.1038/s41534-022-00527-1

In classical and single-particle settings, non-trivial band topology always gives rise to robust boundary modes. For quantum many-body systems, however, multiple topological fermions are not always able to coexist, since Pauli exclusion prevents additional fermions from occupying the limited number of available topological modes. In this work, we show, through IBM quantum computers, how one can robustly stabilize more fermions than the number of topological modes through specially designed 2-fermion interactions. Our demonstration hinges on the realization of BDI- and D-class topological Hamiltonians on transmon-based quantum hardware, and relied on a tensor network-aided circuit recompilation approach. We also achieved the full reconstruction of multiple-fermion topological band structures through iterative quantum phase estimation (IQPE). All in all, our work showcases how advances in quantum algorithm implementation enable noisy intermediate-scale quantum (NISQ) devices to be exploited for topological stabilization beyond the context of single-particle topological invariants.