发表机构
Johannes-Gutenberg University of Mainz; Technical University of Denmark（约翰内斯·古腾堡美因茨大学; 丹麦技术大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出一种基于高斯模糊与滤波的数学形式体系，描述通用光子减法高斯态，通过权衡成功率、前馈兼容性与损耗容限改进猫态、三次相位态和GKP态生成，并建立资源下界。
AI 中文摘要
实现连续变量光学通用且容错的量子计算，缺失的一环是近确定性的非高斯性源。由于缺乏强非线性，概率性的光子减法高斯态仍是最有前景的候选方案。结合高斯测量和单模前馈操作，这些态已被证明能够以高比率提供足够的非高斯性。然而，现有的这些繁殖协议缺乏实验可行性所需的损耗容限。在本工作中，我们引入了一种基于对测量的Fock维格纳函数应用高斯模糊和滤波的数学形式体系，用以描述一般的光子减法高斯态。在我们的表示中，初始压缩、高斯测量和光子损耗都可以理解为总模糊的贡献，并可相应互换。我们发现，这种直观的方法可用于通过权衡成功率、前馈兼容性和损耗容限，来改进猫态、三次相位态和GKP态的生成。在多次光子减法的情况下，这是通过引入一种混合设置变体来实现的，该变体弥合了基于繁殖和基于后选择的协议之间的差距。最后，我们通过引入期望维格纳对数负性作为非高斯性的加性单调量，建立了近确定性生成给定目标态所需资源的一般下界。
英文摘要
A near-deterministic source of non-Gaussianity is the missing piece to reach universal and fault-tolerant quantum computing with continuous-variable optics. Due to a lack of strong non-linearities, the probabilistic photon-subtracted Gaussian states remain the most promising contender. In combination with Gaussian measurements and single-mode feed-forward operations, they have been shown to provide sufficient non-Gaussianity at high rates. However, these existing breeding protocols lack the necessary loss tolerance to be experimentally feasible. In this work, we introduce a mathematical formalism based on the application of a Gaussian blur and filter on the measured Fock Wigner function to describe general photon-subtracted Gaussian states. Within our representation, the initial squeezing, Gaussian measurements, and photon loss can all be understood as contributions to the total blurring and interchanged accordingly. We find that this intuitive approach can be used to find improvements to cat, cubic phase, and GKP state generation by compromising between success rates, feed-forward compatibility, and loss tolerance. In the case of multiple photon subtractions, this is achieved by introducing a hybrid setup variant bridging the gap between protocols based on breeding and post-selection. Finally, we establish a general lower bound on the resources needed to generate a given target state near-deterministically by introducing the expected Wigner logarithmic negativity as an additive monotone of non-Gaussianity.
Comments20 pages, 21 figures
