Joint Entanglement of Topology and Polarization Enables Error-Protected Quantum Registers

TL;DR

This paper demonstrates how joint entanglement of topology and polarization in photonic systems can create error-protected quantum registers, enhancing quantum information processing with topological error suppression.

Contribution

It introduces a novel method of entangling polarization and winding number to protect quantum information against errors in photonic quantum walks.

Findings

Produced entangled two-photon systems with topological analogs of Bell states

Developed a topologically error-protected optical memory register

Generated entangled boundary states with topological protection

Abstract

Linear-optical systems can implement photonic quantum walks that simulate systems with nontrivial topological properties. Here, such photonic walks are used to jointly entangle polarization and winding number. This joint entanglement allows information processing tasks to be performed with interactive access to a wide variety of topological features. Topological considerations are used to suppress errors, with polarization allowing easy measurement and manipulation of qubits. We provide three examples of this approach: production of two-photon systems with entangled winding number (including topological analogs of Bell states), a topologically error-protected optical memory register, and production of entangled topologicallyprotected boundary states. In particular it is shown that a pair of quantum memory registers, entangled in polarization and winding number, with topologically-assisted error suppression can be made with qubits stored in superpositions of winding numbers; as a result, information processing with winding number-based qubits is a viable possibility.