Noisy dynamics of confined quantum walks on a chip

TL;DR

This paper investigates how noise affects confined quantum walks on a chip, revealing disruptions in symmetry, interference pattern changes, and phenomena like localization and oscillations in realistic quantum systems.

Contribution

It introduces the study of noise effects on confined quantum walks using a large on-chip interferometer, highlighting the impact of edges and realistic noise on quantum dynamics.

Findings

Noise disrupts translational symmetry in quantum walks

Edges influence interference patterns and localization

Speed-up effects and coherent oscillations are affected by noise

Abstract

Quantum walks represent an excellent testbed for investigating the interplay between unitary coherent and incoherent dissipative processes. Thanks to photonic quantum interferometers of considerable size, experimental studies could be performed, devoted to investigating the consequences of different sorts of realistic noise in these systems. In this work we employ a 20x20 on-chip multimode interferometer to introduce another key aspect in the problem: the presence of edges in the walker lattice, enforcing a confined evolution. We show how noise can disrupt translational symmetry and reshape interference patterns. The non trivial probability distributions obtained along the temporal evolution of the system demonstrate how speed up effects, localization and coherent oscillations are pillar concepts to be fully characterized and understood when applied in realistic quantum dynamics.