Experimental engineering of arbitrary qudit states with discrete-time quantum walks

TL;DR

This paper demonstrates the use of discrete-time quantum walks in photonics to generate and measure arbitrary high-dimensional qudit states, advancing quantum state engineering capabilities.

Contribution

It introduces a linear-optics platform for engineering and measuring arbitrary six-dimensional qudit states using quantum walks in photon orbital angular momentum.

Findings

Successful preparation of various six-dimensional qudit states

Feasibility of quantum walk-based state engineering in photonics

Potential for broad applications in quantum technologies

Abstract

The capability to generate and manipulate quantum states in high-dimensional Hilbert spaces is a crucial step for the development of quantum technologies, from quantum communication to quantum computation. One-dimensional quantum walk dynamics represents a valid tool in the task of engineering arbitrary quantum states. Here we affirm such potential in a linear-optics platform that realizes discrete-time quantum walks in the orbital angular momentum degree of freedom of photons. Different classes of relevant qudit states in a six-dimensional space are prepared and measured, confirming the feasibility of the protocol. Our results represent a further investigation of quantum walk dynamics in photonics platforms, paving the way for the use of such a quantum state-engineering toolbox for a large range of applications.