Distillation of continuous variable qudits from single photon sources: A cascaded approach

TL;DR

This paper introduces a linear optical cascaded setup using single photon sources and detectors to generate high-fidelity continuous variable quantum states, including cat states and GKP states, simplifying state creation for quantum technologies.

Contribution

It presents a novel cascaded linear optical approach that produces a variety of nonclassical states with high fidelity, using only single photon sources and detectors, and accounts for experimental imperfections.

Findings

Generated displaced higher photon states with 100% fidelity.

Produced Schrödinger cat states above 98% fidelity.

Created GKP resource states with 99% fidelity.

Abstract

Creation of high fidelity photonic quantum states in the continuous variable regime is indispensable for the implementation of quantum technologies universally. However, this is a challenging task as it requires higher nonlinearity or larger Fock states. In this article, we surmount this necessity by using a linear optical setup with a cascaded arrangement of beam splitters that relies solely on single photon sources and single photon detectors to tailor desired single mode nonclassical states. To show the utility of this setup, we demonstrate the generation of displaced higher photon states with unit fidelity and the family of Schrodinger cat states above $98\%$ fidelity. In addition, we manifest the generation of GKP resource states, such as ON states and weak cubic phase states with $99\%$ fidelity. Creating such a variety of important states in this single setup is made feasible by stating the output in the form of displaced qudits. This figure of merit facilitates efficient identification and optimization of input parameters required to generate the target single mode quantum states. We also account for the experimental imperfections by incorporating detector inefficiencies and non-unit single photon sources. This cascaded setup will assist the experimentalists to explore the feasible creation of target states using currently available resources, such as single photon sources and single photon detectors.