Distributed quantum computation via optical fibres

A Quantum Network Node with Crossed Optical Fibre Cavities

Quantum networks provide unique possibilities for resolving open questions on entanglement and promise innovative applications ranging from secure communication to scalable computation. While two quantum nodes coupled by a single channel are adequate for basic quantum communication tasks between two parties, fully functional large-scale quantum networks require a web-like architecture with multiply connected nodes. Efficient interfaces between network nodes and channels can be implemented with optical cavities. Using two optical fibre cavities coupled to one atom, we here realise a quantum net…

基于星型量子网络上非局域CNOT门的猫码保护受控量子通信

Cat-Code-Protected Controlled Quantum Communication via Non-Local CNOT Gates over Star Quantum Networks

该研究提出结合猫态编码与非局域CNOT门的受控量子通信协议，通过密度矩阵模拟证明在50公里距离上显著提升保真度，并验证了抗分束器攻击的安全性，为长距离星型量子网络上的纠错受控通信奠定理论基础。

Coherent light scattering from a telecom C-band quantum dot

Quantum networks have the potential to transform secure communication via quantum key distribution and enable novel concepts in distributed quantum computing and sensing. Coherent quantum light generation at telecom wavelengths is fundamental for fibre-based network implementations, but Fourier-limited emission and subnatural linewidth photons have so far only been reported from systems operating in the visible to near-infrared wavelength range. Here, we use InAs/InP quantum dots to demonstrate photons with coherence times much longer than the Fourier limit at telecom wavelength. Evidence of t…

Distributed measurement-based quantum computation

We develop a formal model for distributed measurement-based quantum computations, adopting an agent-based view, such that computations are described locally where possible. Because the network quantum state is in general entangled, we need to model it as a global structure, reminiscent of global memory in classical agent systems. Local quantum computations are described as measurement patterns. Since measurement-based quantum computation is inherently distributed, this allows us to extend naturally several concepts of the measurement calculus, a formal model for such computations. Our goal is …

An introduction to one-way quantum computing in distributed architectures

This review provides a gentle introduction to one-way quantum computing in distributed architectures. One-way quantum computation shows significant promise as a computational model for distributed systems, particularly those architectures which rely on probabilistic entangling operations. We review the theoretical underpinnings of one-way quantum computation and discuss the practical issues related to exploiting the one-way model in distributed architectures.

Distributed quantum computation with arbitrarily poor photon detection

In a distributed quantum computer scalability is accomplished by networking together many elementary nodes. Typically the network is optical and inter-node entanglement involves photon detection. In complex networks the entanglement fidelity may be degraded by the twin problems of photon loss and dark counts. Here we describe an entanglement protocol which can achieve high fidelity even when these issues are arbitrarily severe; indeed the method succeeds with finite probability even if the detectors are entirely removed from the network. An experimental demonstration should be possible with ex…

横向容错分布式量子计算中的编码与节点选择：初步研究

Encoding and Node Choices in Transversal Fault-Tolerant Distributed Quantum Computations: An Initial Study

本研究比较了双变量自行车编码和节点选择对横向容错分布式量子计算的影响，指出仅减少纠缠比特消耗并非最佳标准，并展示了特定编码可实现并发逻辑操作。