Subdiffusion via Disordered Quantum Walks

TL;DR

This paper demonstrates experimentally that disordered quantum walks can serve as quantum simulators for subdiffusive phenomena, capturing a wide spectrum from localization to diffusion by controlling disorder levels.

Contribution

It introduces a flexible experimental setup to simulate and explore various subdiffusive behaviors in quantum systems through disordered quantum walks.

Findings

Successfully simulated subdiffusive spreading in quantum walks.

Controlled disorder levels enable exploration of localization and diffusion.

Validated the feasibility of quantum walks as models for complex transport phenomena.

Abstract

Transport phenomena play a crucial role in modern physics and applied sciences. Examples include the dissipation of energy across a large system, the distribution of quantum information in optical networks, and the timely modeling of spreading diseases. In this work, we experimentally prove the feasibility of disordered quantum walks to realize a quantum simulator that is able to model general subdiffusive phenomena, exhibiting a sublinear spreading in space over time. Our experiment simulates such phenomena by means of a finely controlled insertion of various levels of disorder during the evolution of the walker, enabled by the unique flexibility of our setup. This allows us to explore the full range of subdiffusive behaviors, ranging from anomalous Anderson localization to normal diffusion.