We propose a quantum repeater scheme based on single-photon interference, which utilizes multimode quantum memories and two-photon sources. Our proposed scheme significantly reduces stability requirements by several orders of magnitude compared to the conventional scheme.
Quantum repeaters are pivotal in the physical layer of the quantum internet, and quantum repeaters capable of efficient entanglement distribution are necessary for its development. Quantum repeater schemes based on single-photon interference are promising because of their potential efficiency. However, schemes involving first-order interference with photon sources at distant nodes require stringent phase stability of the components, which pose challenges for long-distance implementation. In this paper, we present a quantum repeater scheme that leverages single-photon interference and reduces the difficulty of achieving phase stabilization. Additionally, under specific conditions, our scheme achieves a higher entanglement distribution rate between end nodes compared with the existing schemes. Thus, the proposed approach could lead to improved rates with technologies that are currently unavailable but possible in the future and will ultimately facilitate the development of multimode quantum repeaters. Single-photon interference based quantum repeater schemes are promising due to their potential efficiency. Here, the authors offer a theoretical quantum repeater scheme with reduced complexity of phase stabilization and scope for higher entanglement rates between the end nodes.
We propose a quantum repeater protocol which builds on the well-known Duan-Lukin-Cirac-Zoller (DLCZ) protocol [L. M. Duan, M. D. Lukin, J. I. Cirac, and P. Zoller, Nature (London) 414, 413 (2001)10.1038/35106500], but which uses photon pair sources in combination with memories that allow to store a large number of temporal modes. We suggest to realize such multimode memories based on the principle of photon echo, using solids doped with rare-earth-metal ions. The use of multimode memories promises a speedup in entanglement generation by several orders of magnitude and a significant reduction in stability requirements compared to the DLCZ protocol.
Quantum networking, heralded as the next frontier in communication networks, envisions a realm where quantum computers and devices collaborate to unlock capabilities beyond what is possible with the Internet. A critical component for realizing a long-distance quantum network, and ultimately, the Quantum Internet, is the quantum repeater. As with the race to build a scalable quantum computer with different technologies, various schemes exist for building quantum repeaters. This article offers a gentle introduction to the two-way “all-photonic quantum repeaters,” a recent addition to quantum repeater technologies. In contrast to conventional approaches, these repeaters eliminate the need for quantum memories, offering the dual benefits of higher repetition rates and intrinsic tolerance to both quantum operational errors and photon losses. Using visualization and simple rules for manipulating graph states, we describe how all-photonic quantum repeaters work. We discuss the problem of the increased volume of classical communication required by this scheme, which places a huge processing requirement on the end nodes. We address this problem by presenting a solution that decreases the amount of classical communication by three orders of magnitude. We conclude by highlighting other key open challenges in translating the theoretical all-photonic framework into real-world implementation, providing insights into the practical considerations and future research directions of all-photonic quantum repeater technology.