# A Novel Bulk-Optics Scheme for Quantum Walk with High Phase Stability

## TL;DR

This paper introduces a highly stable, configurable bulk-optics scheme for implementing quantum walks using a one-dimensional lattice of displaced Sagnac interferometers, enabling detailed trajectory control and measurement.

## Contribution

It presents a novel, phase-stable bulk-optics setup for quantum walks that allows full configurability and measurement at any step, advancing experimental capabilities.

## Key findings

- Successful experimental implementation of ordered quantum walks.
- Demonstration of disordered quantum walks with the scheme.
- High phase stability achieved in the optical setup.

## Abstract

A novel bulk optics scheme for quantum walks is presented. It consists of a one-dimensional lattice built on two concatenated displaced Sagnac interferometers that make it possible to reproduce all the possible trajectories of an optical quantum walk. Because of the closed loop configuration, the interferometric structure is intrinsically stable in phase. Moreover, the lattice structure is highly configurable, as any phase component perceived by the walker is accessible, and finally, all output modes can be measured at any step of the quantum walk evolution. We report here on the experimental implementation of ordered and disordered quantum walks.