Density shift plays one of the major roles in the uncertainty of optical lattice clock, thus has attracted lots of theoretical and experimental studies. However, most of the theoretical research considered the single-band and collective approximation, so the density shift of the system at higher temperatures can not be analyzed accurately. Here, we design a numerical algorithm that combines Monte Carlo sampling and exact diagonalization and name it as Multi-Band Sampling Exact Diagonalization (MBSED). The MBSED method considers the collision of atoms between multi-bands, so it can provide the density shift of an optical lattice clock with higher precision. Such an algorithm will benefit the numerical simulation of an optical lattice clock, and may also be used in other platforms of quantum metrology. In addition, through our numerical simulation, we also found that the density shift of Rabi spectrum is slightly non-linear with atom number.
Filter-assisted quantum subspace diagonalization via wavefunction sparsity engineering
RIKEN Center for Computational Science (R-CCS)（理化学研究所计算科学中心）；RIKEN Center for Quantum Computing (RQC)（理化学研究所量子计算中心）；RIKEN Pioneering Research Institute (PRI)（理化学研究所先导研究本部）；RIKEN Center for Emergent Matter Science (CEMS)（理化学研究所新物质科学中心）
Modern Approaches to Exact Diagonalization and Selected Configuration Interaction with the Adaptive Sampling CI Method
在选定的CI，包括自适应采样配置相互作用（ASCI）算法及其热浴扩展的最新进展，ASCI方法的竞争力与最准确的技术，因此在解决量子哈密顿越来越强大的工具。在这项工作中，我们表明，一个有用的范例生成高效的选择CI/精确对角化算法是由快速排序算法驱动的，以同样的方式迭代对角化是基于矩阵向量乘法的范例。我们提出了几个新的算法，执行选定的CI，其中包括新的ASCI搜索，动态位屏蔽，快速轨道旋转，快速对角矩阵元素，和残留数组的所有部分。这里提出的算法是快速和可扩展的，我们发现，因为它们是建立在快速排序算法，它们比我们考虑的所有其他方法更有效。在介绍了这些技术之后，我们提出了应用于大范围系统和基组的ASCI结果，以证明可以用现代方法和硬件在全CI水平上实际处理的模拟类型，为G1数据集提供了双zeta和三zeta基准数据。这些计算中最大的是Si $_{2}$ H $_{6}$，它模拟了152个轨道中的34个电子。我们还提出了一些初步的结果，快速确定性微扰理论模拟，使用哈希函数，以保持高效率处理大的基集。
Thermal aliases in quantum noise: sampling clocks and pulse widths
Southern University of Science and Technology（南方科技大学）；International Quantum Academy, Shenzhen（深圳量子研究院）；Shenzhen Branch, Hefei National Laboratory（合肥国家实验室深圳分部）
Quantum Simulation of Ligand-like Molecules through Sample-based Quantum Diagonalization in Density Matrix Embedding Framework
Qclairvoyance Quantum Labs（Qclairvoyance量子实验室）；The University of Arizona（亚利桑那大学）；SRM Institute of Science and Technology（SRM科学与技术学院）；Indian Institute of Technology Bombay（孟买印度理工学院）
An Iterative Dual-Channel Neural Quantum State Algorithm for Selected Configuration Interaction
National Yang Ming Chiao Tung University（国立阳明交通大学）；National Center for High-performance Computing, National Institutes of Applied Research（国家高性能计算中心，国家应用研究学院）；Chung Yuan Christian University（中原大学）
