Multi-Dimensional Quantum Walks: a Playground of Dirac and Schr\"{o}dinger Particles

TL;DR

This paper introduces a novel multi-dimensional discrete-time quantum walk model that simulates extended Dirac and Schrödinger equations, enabling exploration of topological features and higher-order topological materials in two dimensions.

Contribution

It presents a new multi-dimensional quantum walk framework that accurately models extended Dirac and Schrödinger equations, revealing topological phenomena and edge/corner states.

Findings

DTQW simulates 2D Dirac and Schrödinger equations

Reveals topological features and states in 2D systems

Can generate edge and corner states through coin manipulation

Abstract

We propose a new multi-dimensional discrete-time quantum walk (DTQW), whose continuum limit is an extended multi-dimensional Dirac equation, which can be further mapped to the Schr\"{o}dinger equation. We show in two ways that our DTQW is an excellent measure to investigate the two-dimensional (2D) extended Dirac Hamiltonian and higher-order topological materials. First, we show that the dynamics of our DTQW resembles that of a 2D Schr\"{o}dinger harmonic oscillator. Second, we find in our DTQW topological features of the extended Dirac system. By manipulating the coin operators, we can generate not only standard edge states but also corner states.