JPS Hot Topics

Recent advances in experimental techniques used for probing and controlling nanofabricated devices have stimulated a strong interest in theoretically studying their nonequilibrium properties. In thermal equilibrium, electrons follow the Fermi–Dirac distribution, whereas under nonequilibrium conditions, the electron distribution generally deviates from the Fermi–Dirac form. A typical example of this is a nanowire connected to two […]

Superconductivity is a remarkable quantum phenomenon in which electrons form paired bound states, known as Cooper pairs, leading to zero electrical resistance. Bardeen–Cooper–Schrieffer (BCS) theory has long provided the microscopic foundation for conventional superconductivity, describing Cooper pairs with antiparallel electron spins: spin‑singlet pairing. This theory explains a wide range of superconducting materials. By contrast, electrons […]

Quasicrystals (QCs) have no periodicity of atoms but possess structural order. However, their electronic states and physical properties are obscure. Periodic crystals with local atomic configurations common to those of QCs exist and are referred to as approximant crystals (ACs). ACs are unique solids that can be interpolated between conventional periodic crystals and QCs. Rare-earth-based […]

Noble metal surfaces such as gold feature a Shockley surface state and a layer of electrons confined to the topmost atomic layers. The broken crystal inversion symmetry at the surface generates a strong perpendicular electric field, lifting the spin degeneracy and splitting the electronic state into two distinct rings, each with an opposite in-plane spin […]

The two-dimensional CP(1) model is typically investigated as a toy model of quantum chromodynamics (QCD), as it shares several essential features with QCD, including asymptotic freedom and the presence of a topological θ term. In strongly interacting systems such as low-energy QCD, where nonperturbative effects are key, lattice field theory provides an effective framework for […]

Where did heavy elements (e.g., gold, platinum, and rare earths) originate? Of roughly 7,000 atomic nuclei predicted by theoretical models, only approximately 3,300 have been observed. Each newly discovered isotope adds a piece to the “nuclear chart”—a vast map of every possible combination of protons and neutrons. Filling in this chart is essential for understanding […]

Crystals that lack mirror and inversion symmetries are known as chiral crystals; that is, their atomic structures cannot be superimposed onto their mirror images. The collective vibrations of the atoms in a crystal are quantized as bosonic quasiparticles called phonons. Each phonon carries an energy ℏω, where ℏ is the reduced Planck constant, and ωis […]

This study focuses on one of the most intriguing electrical phenomena in modern physics: the topological Hall effect (THE). In the ordinary Hall Effect, a magnetic field simply pushes the flowing electrons sideways; however, the deflection is caused by a hidden internal force. This effect occurs when electrons encounter a complex swirling magnetic texture—often a tiny, […]

The human heart functions as a highly efficient fluid pump, maintaining circulation through organized blood-flow patterns. Characteristic vortex-like structures arise within the left ventricle—the main pumping chamber of the heart—facilitating smooth blood filling and ejection. In patients with cardiovascular diseases, the vortex-like structures are disturbed, reflecting impaired cardiac function. However, conventional diagnostic tools, such as […]

Solitons, originally defined as a special class of exact solutions in classical integrable systems, are now broadly employed across many areas of physics to describe spatially localized excited states that arise from the interplay between nonlinearity and dispersion, including in non-integrable systems. In condensed matter physics, representative examples include soliton lattices in chiral magnets, spinor […]