近日，日本东京大学Akira Furusawa课题组与理化研究所（RIKEN）量子计算中心的Atsushi Sakaguchi合作，成功实现了量子隐形传态的无开关时域光量子计算。相关成果已于2023年3月13日在国际学术期刊《物理评论A》上发表。

该研究团队提出了一种不需要高要求光开关的光量子计算平台。他们的方法基于连续变量测量的量子计算，其中，研究人员修改了量子纠缠的结构，使其不是典型的团簇态，这样可以使用量子隐形传态协议代替光开关和重路由。他们架构中的量子纠缠结构具有额外的模式，允许量子态沿着团簇态传送进出计算，这一任务通常需要光开关。研究人员还概述了如何将他们的平台与Gottesman-Kitaev-Preskill编码结合起来，这是目前最有前途的连续变量系统编码方式。

据悉，光开关和重路由网络在光量子计算机中被认为是光量子计算中必不可少的组分部分，它们用于将必要的量子态注入和弹出光量子计算机中。然而，实际的光开关和重路由网络在实验上具有极大的挑战性，因为它们必须具有极低的损耗、小的开关时间、高的重复率和最小的光学非线性，这些要求难以同时实现。

附：英文原文

Title: Switching-free time-domain optical quantum computation with quantum teleportation

Author: Warit Asavanant, Kosuke Fukui, Atsushi Sakaguchi, Akira Furusawa

Issue&Volume: 2023/03/13

Abstract: Optical switches and rerouting networks are considered essential in optical quantum computers where they are used for injection and dejection of the necessary quantum states into an optical quantum computer. Practical optical switches and rerouting networks are, however, experimentally challenging as they must have extremely low loss, small switching time, high repetition rate, and minimum optical nonlinearity, requirements that are difficult to achieve simultaneously. In this paper, we present an optical quantum computation platform that does not require such optical switches. Our method is based on continuous-variable measurement-based quantum computation where, instead of the typical cluster states, we modify the structure of the quantum entanglement, so that the quantum teleportation protocol can be employed instead of optical switching and rerouting. The quantum entanglement structure in our architecture has additional modes that allow quantum states to be teleported in or out of the computation along the cluster state, a task that normally requires optical switches. We also outline how to combine our platform with Gottesman-Kitaev-Preskill encoding, the currently most promising encoding for a continuous-variable system.

DOI: 10.1103/PhysRevA.107.032412

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.107.032412