JPS Hot Topics

Magnetic atoms primarily exhibit the properties of magnetic dipoles. In addition to magnetic dipoles general, solid-state spins have electric quadrupoles and magnetic octupoles known as typical multipole degrees of freedom. Magnetic dipoles can be coupled to a magnetic field and are easily detectable. However, directly observing the characteristics of multipoles is challenging because of the […]

Magnetic skyrmions are nanoscale, vortex-like collections of magnetic moments that appear in some magnetic materials. These are arranged in a stable, swirling pattern, forming a topologically protected structure, meaning that they cannot be easily destroyed or transformed. This stability, and the ability to be driven by ultra-low currents, make magnetic skyrmions promising for next-generation ultra-low […]

First introduced in 1970, the large-N limit in gauge theories has become a fundamental approach in theoretical physics. Originally developed to understand the strong nuclear force—one of the four fundamental forces of nature—large-N gauge theories have since become critical for addressing challenges in quantum gravity as well. In this study, we examined the thermodynamic properties […]

In recent years, a novel electronic state called the “electronic nematic phase” has attracted much attention. The electronic nematic phase is characterized by rotational symmetry breaking driven by electronic degrees of freedom, such as spins and orbitals, and behaves like a liquid crystal. Iron-based superconductors (IBSs), which are unconventional high-temperature superconductors, are prominent candidates in […]

Dielectric materials are used in various electronic devices, such as capacitors and actuators. At the atomic scale, the positively and negatively charged ions in these devices are displaced from their original positions. Therefore, observing these displacements is essential for improving the performance of electronic devices and developing new dielectric materials. BaTiO3 has a high capacity […]

 Weyl semimetals are a class of materials characterized by the presence of Weyl points where the valence and conduction bands touch linearly. Electrons near these points behave as relativistic fermions called Weyl fermions, contributing to topological magnetoelectric responses, such as the anomalous Hall effect. The concept of chiral gauge field was introduced to understand these […]

When attempting to reach the exact ground states of interacting quantum systems, the computational cost increases exponentially with the system size in most cases and is thus intractable, which is known as an NP-hard problem. Unless accurate quantum computers become available, approximate but sufficiently accurate algorithms that are applicable to conventional computers need to be […]

Increasing temperatures to higher than the surrounding temperature is easier compared with decreasing temperatures to lower than the surrounding temperature. Many refrigerators and air conditioners use latent heat when liquid evaporates. Additionally, the Joule-Thomson effect and thermoelectric effect, termed the Peltier effect, have been used for cooling. Aligning magnetic moments using an external magnetic field […]

Linear or nonlinear dynamical models can explain various real-life phenomena. While linear approximations work well for some systems, others can only be explained by nonlinear models, which greatly complicates calculations. One such phenomenon is the elastic two-body quantum scattering of nucleons. This scattering problem is described by the Variable Phase Approximation (VPA), a nonautonomous nonlinear […]