A two-way photonic quantum entanglement transfer interface

TL;DR

This paper demonstrates an experimental quantum interface enabling two-way entanglement transfer between orbital angular momentum and time-energy degrees of freedom, achieving high fidelity and advancing quantum communication networks.

Contribution

It introduces a novel two-way entanglement transfer interface using interferometric cyclic gates for heterogeneous quantum nodes.

Findings

Achieved over 90% fidelity in entanglement transfer

Demonstrated reversible switching between degrees of freedom

Validated the feasibility of the proposed quantum interface

Abstract

A quantum interface for two-way entanglement transfer between orbital angular momentum degree of freedom in free space and time-energy degree of freedom in optical fibers, provides a novel way toward establishing entanglement between remote heterogeneous quantum nodes. Here, we experimentally demonstrate this kind of transfer interface by using two interferometric cyclic gates. By using this quantum interface, we perform two-way entanglement transfer for the two degrees of freedom. The results show that the quantum entangled state can be switched back and forth between orbital angular momentum and time-energy degrees of freedom, and the fidelity of the state before and after switching is higher than 90%. Our work demonstrates the feasibility and high performance of our proposed transfer interface, and paves a route toward building a large-scale quantum communication network.