Flamini Fulvio, Spagnolo Nicolò, Viggianiello Niko, Crespi Andrea, Osellame Roberto, Sciarrino Fabio
Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 5, I-00185, Roma, Italy.
Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche (IFN-CNR), Piazza Leonardo da Vinci, 32, I-20133, Milano, Italy.
Sci Rep. 2017 Nov 9;7(1):15133. doi: 10.1038/s41598-017-15174-2.
Photonic platforms represent a promising technology for the realization of several quantum communication protocols and for experiments of quantum simulation. Moreover, large-scale integrated interferometers have recently gained a relevant role in quantum computing, specifically with Boson Sampling devices and the race for quantum supremacy. Indeed, various linear optical schemes have been proposed for the implementation of unitary transformations, each one suitable for a specific task. Notwithstanding, so far a comprehensive analysis of the state of the art under broader and realistic conditions is still lacking. In the present work we fill this gap, providing in a unified framework a quantitative comparison of the three main photonic architectures, namely the ones with triangular and square designs and the so-called fast transformations. All layouts have been analyzed in presence of losses and imperfect control over the internal reflectivities and phases, showing that the square design outperforms the triangular scheme in most operational conditions. Our results represent a further step ahead towards the implementation of quantum information protocols on large-scale integrated photonic devices.
光子平台是实现多种量子通信协议以及进行量子模拟实验的一项很有前景的技术。此外，大规模集成干涉仪最近在量子计算中发挥了重要作用，特别是在玻色子采样设备以及量子霸权竞赛方面。确实，已经提出了各种线性光学方案来实现酉变换，每种方案都适用于特定任务。尽管如此，到目前为止，在更广泛和现实的条件下对现有技术水平仍缺乏全面分析。在本工作中，我们填补了这一空白，在一个统一的框架内对三种主要的光子架构进行了定量比较，即具有三角形和方形设计的架构以及所谓的快速变换架构。所有布局都在存在损耗以及对内部反射率和相位控制不完善的情况下进行了分析，结果表明在大多数操作条件下，方形设计优于三角形方案。我们的结果朝着在大规模集成光子器件上实现量子信息协议又迈进了一步。
