近日，日本东京大学的Akira Furusawa&Warit Asavanant及其研究团队取得一项新进展。经过不懈努力，他们实现具有传播光容错量子计算的逻辑状态。相关研究成果已于2024年1月19日在国际权威学术期刊《科学》上发表。

该研究团队实现了在通信波长下光传播的GKP量子态，并通过无损耗校正的零差测量进行了验证。这一生成过程基于猫态干涉，并随后进行零差测量。最终的量子态展现出非经典和非高斯特性，其中包括微弱的GKP量子态实例所呈现的三叉戟形状。向更亮、多峰GKP量子比特的改进将成为光量子计算的基础。

据悉，为了利用量子计算机的潜力，必须通过将量子信息编码为适合量子纠错的逻辑状态，来保护量子信息免受错误的影响。Gottesman-Kitaev-Preskill (GKP)量子比特是一个很有前途的候选者，因为所需的多量子比特操作在光学频率上很容易获得。然而，到目前为止，GKP量子比特只在机械和微波频率下得到了证明。

附：英文原文

Title: Logical states for fault-tolerant quantum computation with propagating light

Author: Shunya Konno, Warit Asavanant, Fumiya Hanamura, Hironari Nagayoshi, Kosuke Fukui, Atsushi Sakaguchi, Ryuhoh Ide, Fumihiro China, Masahiro Yabuno, Shigehito Miki, Hirotaka Terai, Kan Takase, Mamoru Endo, Petr Marek, Radim Filip, Peter van Loock, Akira Furusawa

Issue&Volume: 2024-01-19

Abstract: To harness the potential of a quantum computer, quantum information must be protected against error by encoding it into a logical state that is suitable for quantum error correction. The Gottesman-Kitaev-Preskill (GKP) qubit is a promising candidate because the required multiqubit operations are readily available at optical frequency. To date, however, GKP qubits have been demonstrated only at mechanical and microwave frequencies. We realized a GKP state in propagating light at telecommunication wavelength and verified it through homodyne measurements without loss corrections. The generation is based on interference of cat states, followed by homodyne measurements. Our final states exhibit nonclassicality and non-Gaussianity, including the trident shape of faint instances of GKP states. Improvements toward brighter, multipeaked GKP qubits will be the basis for quantum computation with light.

DOI: 10.1126/science.adk7560

Source: https://www.science.org/doi/10.1126/science.adk7560