Rydberg-atom quantum simulators are of keen interest because of their possibilities towards high-dimensional qubit architectures. Here we report three-dimensional conformation spectra of quantum-Ising Hamiltonian systems with programmed qubit connections. With a Rydberg-atom quantum simulator, various connected graphs, in which vertices and edges represent atoms and blockaded couplings, respectively, are constructed in two or three-dimensional space and their eigenenergies are probed during their topological transformations. Star, complete, cyclic, and diamond graphs, and their geometric intermediates, are tested for four atoms and antiprism structures for six atoms. Spectroscopic resolution (∆E/E) less than 10% is achieved and the observed energy level shifts and merges through structural transformations are in good agreement with the model few-body quantum-Ising Hamiltonian.

Resistive switching properties of hafnium oxide and manganese oxide double-layer films sandwiched between Pt bottom electrode and Ag top electrode have been investigated. The devices exhibited bipolar resistive switching. As compared with the devices with hafnium oxide and manganese oxide single layer, the double-layered devices showed better resistive switching behaviors, including forming-free behavior, a high resistance ratio (>105–6), and good retention properties. The forming-free behavior of the bilayer device is very useful for resistive random access memory applications. The high resistance ratio is beneficial to distinguish the storage information. The formation and disruption of Ag conductive filament in the oxide layers led to the resistance changes.

KAGRA is a gravitational-wave (GW) detector constructed in Japan with two unique key features: It was constructed underground, and the test-mass mirrors are cooled to cryogenic temperatures. These features are not included in other kilometer-scale detectors but will be adopted in future detectors such as the Einstein Telescope. KAGRA performed its first joint observation run with GEO600 in 2020. In this observation, the sensitivity of KAGRA to GWs was inferior to that of other kilometer-scale detectors such as LIGO and Virgo. However, further upgrades to the detector are ongoing to reach the sensitivity for detecting GWs in the next observation run, which is scheduled for 2022. In this article, the current situation, sensitivity, and future perspectives are reviewed.

The goal of this study is to identify geometrical differences in the boundary structure of cells using scanning electron microscopy (SEM). A variety of cancer tissues have been demonstrated to possess their own structural identities defined as fractal dimensions when they are grown in vivo. Fractal structure is clearly characterized by recursive self-similarity over scales suggesting that the fractal geometry of cancer could be applicable to cells as well as to tissues. However, the fractal geometry of cancer in a single cell has not been elucidated. Here we investigate the fractal structure of several different cell lines established from normal and cancer tissues using SEM. The data from SEM imaging allowed us to determine the fine boundary structure of human breast cells including MCF10A (normal cell line), MCF7 (weakly invasive cell line), and MDA-MB231 (highly invasive cell line). A box-counting analysis of cell boundaries extracted from the SEM images revealed that each cell line has a diagnostic inclination toward a fractal structure although it is not much different from each other.

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