Robust measurement of wave function topology on NISQ quantum computers

TL;DR

This paper introduces a noise-robust method to measure topological invariants of quantum states using NISQ quantum computers, compatible with VQE, enabling characterization of complex quantum phases on current hardware.

Contribution

A novel strategy to measure topological invariants on quantum computers that integrates with VQE and is robust against noise, applicable to both interacting and non-interacting systems.

Findings

Successfully measured topological invariants on quantum hardware.

Demonstrated robustness against local noise.

Mapped quantum phase diagrams on real quantum devices.

Abstract

Topological quantum phases of quantum materials are defined through their topological invariants. These topological invariants are quantities that characterize the global geometrical properties of the quantum wave functions and thus are immune to local noise. Here, we present a strategy to measure topological invariants on quantum computers. We show that our strategy can be easily integrated with the variational quantum eigensolver (VQE) so that the topological properties of generic quantum many-body states can be characterized on current quantum hardware. We demonstrate the robust nature of the method by measuring topological invariants for both non-interacting and interacting models, and map out interacting quantum phase diagrams on quantum simulators and IBM quantum hardware.