# Topological Photonics for Optical Communications and Quantum Computing

## Abstract

**:**

## 1. Introduction

- Superposition concerns the property of quantum objects to stay in a linear combination of multiple states until they are observed;
- Entanglement is defined as the possibility that two or more quantum objects stay intrinsically linked in an intertwined composite state, regardless of how far apart the objects are from one another. Recently, hyperentanglement has been discovered, defined as the entanglement in multiple degrees of freedom (DOFs) of a quantum system, such as the polarization, spatial mode, orbital angular momentum, time-bin and frequency DOFs of photons;
- Measurement regards the collapse and disruption of a quantum state from a coherent, probabilistic superposition state into a discrete one.

- A scalable physical system with well characterized qubits;
- The ability to initialize the state of the qubits to a simple fiducial state;
- Long, relevant decoherence times;
- A universal set of quantum gates;
- A qubit-specific measurement capability.

- A brief description of a vision aiming at the integration of optical communications and quantum optical computing;
- A description of some key concepts and definitions on topological photonics, with a focus on the adoption of orbital angular momentum (OAM) for optical communications, networking and quantum optical computing;
- An overview of the state-of-the-art future challenges and applications.

## 2. Quantum Communications and Quantum Optical Computing

- Infrastructure architectural integration;
- ○
- Management, control and orchestration (abstractions and interfaces) of digital and quantum resources and services;

- Optics integration;
- ○
- Integrated photonic components and sub-system systems;

- Channels integration;
- ○
- Quantum optical vs. classical optical links.

## 3. Topological Photonics and OAM

#### 3.1. Basic Concetps on Topology

#### 3.2. Topological Photonic: Vortex and Qubits

## 4. Quantum Materials

## 5. Conclusions and Outlook

## Funding

## Conflicts of Interest

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Manzalini, A. Topological Photonics for Optical Communications and Quantum Computing. *Quantum Rep.* **2020**, *2*, 579-590.
https://doi.org/10.3390/quantum2040040

**AMA Style**

Manzalini A. Topological Photonics for Optical Communications and Quantum Computing. *Quantum Reports*. 2020; 2(4):579-590.
https://doi.org/10.3390/quantum2040040

**Chicago/Turabian Style**

Manzalini, Antonio. 2020. "Topological Photonics for Optical Communications and Quantum Computing" *Quantum Reports* 2, no. 4: 579-590.
https://doi.org/10.3390/quantum2040040