JPS Hot Topics

Machine learning techniques have grown rapidly in recent years, and have become indispensable in many fields, including physics. For example, neural networks effectively represent wave functions in many-body quantum systems, where they have been applied to detect phase transitions. Moreover, Monte Carlo sampling and molecular dynamics simulations can be made significantly faster using machine learning. […]

Transition metal-pnictide systems have been extensively studied for decades owing to their unique magnetic properties. Among these, chromium arsenide (CrAs) and manganese phosphide (MnP) are the first chromium and manganese based superconductors, exhibiting unconventional superconductivity under high pressure. CrAs starts superconducting at around 1.2 gigapascals (GPa), while MnP requires pressure as high as 8 GPa. […]

Transport phenomena, especially electron transport, are fundamental processes that are widely studied due to their practical applications in daily life. The Hall effect, for instance, is commonly applied in electronic devices to detect magnetic fields. The topological Hall effect is another such phenomenon, that occurs when electrons are coupled to a non-coplanar magnetic texture with […]

At lower temperatures, as thermal agitation decreases, electrons can arrange themselves into ordered states, leading to distinctive material properties like magnetism and superconductivity. In the 1960s, the concept of the ‘excitonic insulator’ was introduced as an ordered state of electron-hole pairs. This phase can be observed in narrow-gap semiconductors or band-overlapped semimetals, where electrons from […]

Many-body localization is a phenomenon in quantum many-body systems that prevents the system from reaching thermal equilibrium and chaos. This has been observed in various systems and has been a major focus of research. A widely used measure of quantum chaoticity in these systems is the “gap ratio distribution,” which describes the distribution of the […]

The Tanabe–Sugano diagrams, developed by Yukito Tanabe and Satoru Sugano in 1954, show how the energy levels of electrons in the d-orbitals split under the influence of a ligand field. These diagrams help reveal the details about optical responses, magnetic properties, and electronic behaviors of transition-metal complexes and compounds. Commemorating 70 years of the Tanabe–Sugano […]

One of the intriguing phenomena in the field of condensed matter physics is the charge density wave or CDW. It is a periodic modulation of electronic charge and atomic positions in materials, similar to the formation of intricate patterns, like waves. This state is typically induced by the Peierls mechanism, driven by Fermi surface nesting that […]

The 2011 Great East Japan Earthquake damaged the Japan Research Reactor 3 (JRR-3), owned by the Japan Atomic Energy Agency, leading to its shutdown. Thanks to the extraordinary efforts of many people, after nearly 10 years, in February 2021, the reactor resumed operation after meeting all the strict safety standards. Since then, users who had […]

The bound state at positive energy or the bound state in the continuum (BIC) was first predicted by von Neumann and Wigner in 1929. Unlike conventional bound states, which can only exist at discrete negative energies below continuum spectra of scattering states with positive energies, BICs make use of nonlocality of potential to confine themselves […]

Symmetry is a fundamental concept of physics that describes how the laws of physics remain unchanged under certain transformations. Generalized symmetries are an extension of this concept, which, in recent times, has been applied to the analysis of quantum field theories. Among these are non-invertible symmetries which do not have inverse elements and cannot be […]