Stabilizing multiple topological fermions on a quantum computer

Abstract

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 of unprecedented complexity on transmon-based quantum hardware, and crucially relied on tensor network-aided circuit recompilation approaches beyond conventional trotterization. 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 enables NISQ-era quantum computers to be exploited for topological stabilization beyond the context of single-particle topological invariants.

Critical hybridization of skin modes in coupled non-Hermitian chains

“…1) where within each chain, the intra-unit cell and inter-unit cell couplings are respectively non-reciprocal and reciprocal in nature. There are various platforms, such as photonic, optical, and topolectrical systems, through which such coupled systems can be realized [57,72,[75][76][77][78][79][80]. We emphasize that the results and characteristics of our coupled model are independent of the choice of the implementation platform so that the most easily accessible platform can be chosen for the experimental realization.…”

Realizing symmetry-protected topological phases in a spin-1/2 chain with next-nearest-neighbor hopping on superconducting qubits

“…It is therefore natural to consider using digital quantum computers to study models with interactions beyond nearest-neighbor (NN) interactions as such couplings are reported to host exotic topological phases [67,68] but are difficult to engineer in conventional analog quantum simulators. Early efforts in this direction include simulation of an extended Kitaev chain model with next-nearest neighbor (NNN) interactions on a superconducting quantum device [69]. Another relevant model is a spin-1/2 chain with NNN interactions, which is predicted to host two types of SPT phases with distinct string-order parameters and edge excitations [70].…”