Entanglement represents ``\textit{the}'' key resource for several applications of quantum information processing, ranging from quantum communications to distributed quantum computing. Despite its fundamental importance, deterministic generation of maximally entangled qubits represents an on-going open problem. Here, we design a novel generation scheme exhibiting two attractive features, namely, i) deterministically generating different classes -- namely, GHZ-like, W-like and graph states -- of genuinely multipartite entangled states, ii) without requiring any direct interaction between the qubits. Indeed, the only necessary condition is the possibility of coherently controlling -- according to the indefinite causal order framework -- the causal order among the unitaries acting on the qubits. Through the paper, we analyze and derive the conditions on the unitaries for deterministic generation, and we provide examples for unitaries practical implementation. We conclude the paper by discussing the scalability of the proposed scheme to higher dimensional genuine multipartite entanglement (GME) states and by introducing some possible applications of the proposal for quantum networks.

翻译：纠缠是量子信息处理（从量子通信到分布式量子计算）多项应用中的关键资源。尽管其基础重要性不言而喻，但最大纠缠量子比特的确定性生成仍是一个悬而未决的开放问题。本文设计了一种新型生成方案，具有两大吸引特性：i) 可确定性生成不同类别的真正多方纠缠态——即类GHZ态、类W态和图态；ii) 无需量子比特之间发生直接相互作用。实际上，唯一必要条件是能够根据不定因果序框架，相干地控制作用于量子比特上的酉算子之间的因果顺序。本文分析并推导了确定性生成所需的酉算子条件，并给出了酉算子的实际实现示例。最后，我们讨论了所提方案向高维真正多方纠缠态扩展的可扩展性，并介绍了该方案在量子网络中的若干可能应用。