Phase Transitions and Noise Robustness of Quantum Graph States
Chuo University（中央大学）；The University of Electro-Communications（电气通信大学）；Sanyo-Onoda City University（山阳小野田市立大学）；Hiroshima University（广岛大学）；Mitsubishi Electric Corporation（三菱电机株式会社）；NTT Corporation（日本电信电话株式会社）
Graph states are entangled states that are essential for quantum information processing. As experimental advances enable the realization of large-scale graph states, efficient fidelity estimation methods are crucial for assessing their robustness against noise. However, calculations of exact fidelity become intractable for large systems due to the exponential growth in the number of stabilizers. In this work, we show that the fidelity between any ideal graph state and its noisy counterpart under IID Pauli noise can be mapped to the partition function of a classical spin system, enabling efficient computation via statistical mechanical techniques. Using this approach, we analyze the fidelity for regular graph states under depolarizing noise and uncover the emergence of phase transitions in fidelity between the pure-state regime and the noise-dominated regime. Specifically, in 2D, phase transitions occur only when the degree satisfies $d\ge 6$, while in 3D they already appear at $d\ge 5$. However, for graph states with excessively high degree, such as fully connected graphs, the phase transition disappears. Robustness of graph states against noise is thus determined by their connectivity and spatial dimensionality. Graph states with lower degree and/or dimensionality, which exhibit a smooth crossover, demonstrate greater robustness, while highly connected or higher-dimensional graph states are more fragile. Extreme connectivity, as the fully connected graph state possesses, restores robustness. Furthermore, we show that the fidelity can be rewritten in the form of the partition function of a constraint-percolation problem. Within this picture, we discuss the qualitative difference between 2D regular graph states with $d=6$ and $d=5$ regarding the presence or absence of a phase transition, as well as the suppressed critical behavior of fully connected graph states.
Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano（电子、信息与生物工程系，米兰理工学院）；Department of Electrical and Computer Engineering, National Yang Ming Chiao Tung University（电子与计算机工程系，国立阳明交通大学）
Robustness of non-abelian holonomic quantum gates against parametric noise
本文对一类非阿贝尔完整量子门的鲁棒性进行了数值研究。我们考虑到由于控制场的随机波动的参数噪声驱动的时间相关的哈密顿沿绝热环。所用的性能估计器是无噪声和有噪声完整门之间的状态保真度。我们进行了我们的分析与不同的相关时间，我们发现，有噪声的完整门似乎是接近无噪声的“短”和“长”噪声相关时间。这个结果可以解释为完整算子的几何性质的结果。我们的模拟是通过使用与激子方案有关的参数来实现完整量子计算的[P.Solinas et al.Phys.Rev.B67，121307（2003）]
Diagnosing Quantum Circuits: Noise Robustness, Trainability, and Expressibility
Yau Mathematical Sciences Center, Tsinghua University（清华大学丘成桐数学科学中心）；Yanqi Lake Beijing Institute of Mathematical Sciences and Applications（北京雁栖湖应用数学研究院）；Institute for Interdisciplinary Information Sciences, Tsinghua University（清华大学交叉信息研究院）；Department of Mathematics, Tsinghua University（清华大学数学系）
Robustness of Quantum-Enhanced Adaptive Phase Estimation
Institute for Quantum Science and Technology（量子科学与技术研究所）；University of Calgary（卡尔加里大学）；Program in Quantum Information Science（量子信息科学项目）；Canadian Institute for Advanced Research（加拿大高级研究 institute）；Toronto, Ontario M5G 1M1, Canada（加拿大安大略省多伦多M5G 1M1）
Using Interaction-Based Readouts to Approach the Ultimate Limit of Detection Noise Robustness for Quantum-Enhanced Metrology in Collective Spin Systems
Optimal Provable Robustness of Quantum Classification via Quantum Hypothesis Testing
ETH Zürich（苏黎世联邦理工学院）；Shanghai Jiao Tong University（上海交通大学）；University of Michigan-Shanghai Jiao Tong University Joint Institute（上海交通大学密歇根学院）；University of Illinois（伊利诺伊大学）
Noise robustness and experimental demonstration of a quantum generative adversarial network for continuous distributions
University of Toronto（多伦多大学）；Zapata Computing Inc.（Zapata Computing 公司）；Vector Institute（向量研究所）；Canadian Institute for Advanced Research (CIFAR)（加拿大高等研究院）
