More Like this

1. One-dimensional Luttinger liquids in a two-dimensional moiré lattice

   https://doi.org/10.1038/s41586-022-04514-6  

   Wang, Pengjie; Yu, Guo; Kwan, Yves H.; Jia, Yanyu; Lei, Shiming; Klemenz, Sebastian; Cevallos, F. Alexandre; Singha, Ratnadwip; Devakul, Trithep; Watanabe, Kenji; et al (May 2022, Nature)
2. A three-dimensional photonic topological insulator using a two-dimensional ring resonator lattice with a synthetic frequency dimension

   https://doi.org/10.1126/sciadv.aat2774  

   Lin, Qian; Sun, Xiao-Qi; Xiao, Meng; Zhang, Shou-Cheng; Fan, Shanhui (October 2018, Science Advances)

   In the development of topological photonics, achieving three-dimensional topological insulators is of notable interest since it enables the exploration of new topological physics with photons and promises novel photonic devices that are robust against disorders in three dimensions. Previous theoretical proposals toward three-dimensional topological insulators use complex geometries that are challenging to implement. On the basis of the concept of synthetic dimension, we show that a two-dimensional array of ring resonators, which was previously demonstrated to exhibit a two-dimensional topological insulator phase, automatically becomes a three-dimensional topological insulator when the frequency dimension is taken into account. Moreover, by modulating a few of the resonators, a screw dislocation along the frequency axis can be created, which provides robust one-way transport of photons along the frequency axis. Demonstrating the physics of screw dislocation in a topological system has been a substantial challenge in solid-state systems. Our work indicates that the physics of three-dimensional topological insulators can be explored in standard integrated photonic platforms, leading to opportunities for novel devices that control the frequency of light. 

   more » « less
3. Two-Dimensional Versus Three-Dimensional Symmetric Lifting Motion Prediction Models: A Case Study

   https://doi.org/10.1115/1.4049217  

   Zaman, Rahid; Xiang, Yujiang; Cruz, Jazmin; Yang, James (August 2021, Journal of Computing and Information Science in Engineering)

   null (Ed.)

   Abstract Symmetric lifting is a common manual material handling strategy in daily life and is the main cause of low back pain. In the literature, symmetric lifting is mainly simulated by using two-dimensional (2D) models because of their simplicity and low computational cost. In practice, however, symmetric lifting can generate asymmetric kinetics especially when the lifting weight is heavy and symmetric lifting based on 2D models misses this important asymmetric kinetics information. Therefore, three-dimensional (3D) models are necessary for symmetric lifting simulation to capture asymmetric kinetics. The purpose of this single-subject case study is to compare the optimization formulations and simulation results for symmetric lifting by using 2D and 3D human models and to identify their pros and cons. In this case study, a 10-degrees-of-freedom (DOFs) 2D skeletal model and a 40-DOFs 3D skeletal model are employed to predict the symmetric maximum weight lifting motion, respectively. The lifting problem is formulated as a multi-objective optimization (MOO) problem to minimize the dynamic effort and maximize the box weight. An inverse dynamic optimization approach is used to determine the optimal lifting motion and the maximum lifting weight considering dynamic joint strength. Lab experiments are carried out to validate the predicted motions. The predicted lifting motion, ground reaction forces (GRFs), and maximum box weight from the 2D and 3D human models for Subject #8 are compared with the experimental data. Recommendations are given. 

   more » « less
4. Multiphase field model of cells on a substrate: From three dimensional to two dimensional

   https://doi.org/10.1103/PhysRevE.110.044403  

   Chiang, Michael; Hopkins, Austin; Loewe, Benjamin; Marenduzzo, Davide; Marchetti, M Cristina (October 2024, Physical Review E)

   Multiphase field models have emerged as an important computational tool for understanding biological tissue while resolving single-cell properties. While they have successfully reproduced many experimentally observed behaviors of living tissue, the theoretical underpinnings have not been fully explored. We show that a two-dimensional version of the model, which is commonly employed to study tissue monolayers, can be derived from a three-dimensional version in the presence of a substrate. We also show how viscous forces, which arise from friction between different cells, can be included in the model. Finally, we numerically simulate a tissue monolayer and find that intercellular friction tends to solidify the tissue. Published by the American Physical Society2024 

   more » « less
5. A Tutorial on Learned Multi-dimensional Indexes

   https://doi.org/10.1145/3397536.3426358  

   Al-Mamun, Abdullah; Wu, Hao; Aref, Walid G. (November 2020, SIGSPATIAL '20: Proceedings of the 28th International Conference on Advances in Geographic Information Systems)

   null (Ed.)

   Recently, Machine Learning (ML, for short) has been successfully applied to database indexing. Initial experimentation on Learned Indexes has demonstrated better search performance and lower space requirements than their traditional database counterparts. Numerous attempts have been explored to extend learned indexes to the multi-dimensional space. This makes learned indexes potentially suitable for spatial databases. The goal of this tutorial is to provide up-to-date coverage of learned indexes both in the single and multi-dimensional spaces. The tutorial covers over 25 learned indexes. The tutorial navigates through the space of learned indexes through a taxonomy that helps classify the covered learned indexes both in the single and multi-dimensional spaces. 

   more » « less