Dynamics and energy spectra of aperiodic discrete-time quantum walks

TL;DR

This paper investigates how deterministic aperiodic sequences influence the dynamics and energy spectra of discrete-time quantum walks, revealing the role of diffraction spectra in wavepacket spreading.

Contribution

It introduces a novel analysis of quantum walk dynamics using various aperiodic sequences, linking spectral properties to wavepacket behavior.

Findings

Aperiodic sequences affect quantum walk spreading patterns.

Diffraction spectra characterize wavepacket dynamics.

Different sequences lead to distinct spectral and dynamical regimes.

Abstract

Deterministically aperiodic sequences are an intermediary between periodic sequences and completely random sequences. Materials which are translationally periodic have Bloch-like extended states, while random media exhibit Anderson localisation. Materials constructed on the basis of deterministic aperiodic sequences such as Fibonacci, Thue-Morse, and Rudin-Shapiro exhibit different properties, which can be related to their spectrum. Here, by investigating the dynamics of discrete-time quantum walks using different aperiodic sequences of coin operations in position space and time we establish the role of the diffraction spectra in characterizing the spreading of the wavepacket.