Quantum Information Transfer between a Two-Level and a Four-Level Quantum System

TL;DR

This paper demonstrates a novel scheme for transferring quantum information between a two-level and a four-level quantum system using an optical entangling gate, achieving high fidelity transfers beyond classical limits.

Contribution

It introduces and experimentally validates a method for quantum information transfer between different-dimensional quantum systems, expanding the capabilities of quantum communication.

Findings

Quantum information transfer fidelities range from 0.700 to 0.917.

Successful transfer of quantum information between 2D and 4D photons.

Demonstrates entangling operations beyond two-level systems.

Abstract

Quantum mechanics provides a disembodied way to transfer quantum information from one quantum object to another. In theory, this quantum information transfer can occur between quantum objects of any dimension, yet the reported experiments of quantum information transfer to date have mainly focused on the cases where the quantum objects have the same dimension. Here we theoretically propose and experimentally demonstrate a scheme for quantum information transfer between quantum objects of different dimensions.By using an optical qubit-ququart entangling gate, we observe the transfer of quantum information between two photons with different dimensions, including the flow of quantum information from a four-dimensional photon to a two-dimensional photon and vice versa.The fidelities of the quantum information transfer range from 0.700 to 0.917, all above the classical limit of 2/3. Our work sheds light on a new direction for quantum information transfer and demonstrates our ability to implement entangling operations beyond two-level quantum systems.