The special topics edition of the Journal of the Physical Society of Japan presents five new review articles offering cutting-edge information on the emerging field of topological photonics.

We demonstrate a new type of magnetoelectric effect in the pyroelectric ferrimagnet CaBaCo₄O₇—modulating its phase stability depending on the relative direction between the electric field and its electric polarization, enabling new material design strategies.

This work provides the first observation of the superconducting gap in molecular superconductors and their gap symmetry using photoemission spectroscopy, which will significantly accelerate the study of molecular conductors.

Encoding fracture physics in neural networks provides fast and accurate estimates of the distribution of fragment sizes in shrinkage-induced cracking and facilitates Bayesian analysis for a deeper physical understanding of fractures.

We quantitatively elucidated for the first time the electronic polarization structure in epitaxial YbFe₂O₄ thin films by measuring the angle dependence of second-order nonlinear optical signals.

Phonon-induced current noise in carbon nanotubes shows multiple resonance peaks in the high-frequency regime, some of which cannot be explained solely by energy and momentum conservation or by harmonic selection rules. These findings highlight nontrivial electron–anharmonic phonon interactions governing quantum transport in carbon nanotubes.

Jewel beetles enhance their dazzling iridescence by appropriately adjusting the thickness of the surface layers in their natural multilayer reflectors, thereby achieving constructive optical interference.

This special topics edition of the Progress of Theoretical and Experimental Physics covers a symposium celebrating the 50-year history of the Kobayashi–Maskawa Theory, highlighting its impact from theoretical and experimental perspectives.

This work provides a theoretical demonstration of piezomagnetic effects in an organic altermagnet, arising from strain-induced asymmetries in exchange interactions and orbital degrees of freedom, thereby revealing new opportunities for organic spintronics.

A newly discovered phase in layered organic conductors exhibits enhanced magnetic susceptibility, indicating two-dimensional charge ordering, which is distinct from both the charge-glass and three-dimensional charge-ordered phases.

This review explores recent experimental advances in the emerging field of orbitronics, focusing on orbital current mechanisms and orbitronic phenomena, providing key research directions for developing energy-efficient memory devices.

Antisite defects in Fe_₂VAl create resonance states that boost hole scattering, which shifts carrier dominance to electrons and reverses thermoelectric polarity, thereby offering a new path for material design.

Discovery of new superheavy elements require beams beyond the emblematic Calcium-48. Intense titanium-50 beams open a new route used in the present tentative synthesis of oganesson (Z=118).

This study identifies physical processes behind the simple unified formula for orbital magnetic susceptibility in solids, including contributions from four different sources, offering new insights into the understanding of the nature of Bloch electrons in magnetic field.

A novel synergy between an active matter model and a machine learning algorithm has been discovered, revealing the possibility of new phases in active matter.

Vanadium dioxide exhibits a current-induced non-equilibrium phase transition that is distinct from Joule heating, and is characterized by non-linear conduction and collective electron behavior under surprisingly small electric fields.

This study explores dimensionality reduction in fluid dynamics using “autoencoder”, a nonlinear machine learning method, to represent complex flows with fewer variables and more efficiently than with traditional linear techniques.  

This study demonstrates that the fourth moment of nuclear charge density obtained from electron scattering helps estimate neutron distributions—enabling reliable neutron-skin thickness measurement relevant to nuclear physics and astrophysics.

We theoretically demonstrate the emergence of finite-momentum superconductivity in a two-dimensional altermagnet with Rashba-type spin–orbit coupling (RSOC), where anisotropic deformations of the Fermi surfaces stabilize this unconventional superconducting state.

This article explores recent developments in electromagnons, which are terahertz excitations in spin-spiral multiferroics. Learn how spin-driven ferroelectricity enables nonreciprocal optical effects and offers new possibilities for terahertz technologies.

A softening phenomenon below 1 K was discovered in diamond, the hardest known material, suggesting the presence of a hidden quantum ground state with electric quadrupolar degrees of freedom arising from lattice defects.

”Second-order fringes” rings a bell? ”Which-path” echoes a quantum sequel?
”Spoofing decoherence” sounds like a plan? All this is not about photons, actu-
ally. Fast forward, and let the answer reveal itself soon.  Oops, too loud?

Ferroaxial domains were visualized in the glaserite-type compound Na₂BaM(PO₄)₂ (M = divalent metal) using the linear electrogyration effect with polarization microscopy combined with a field-modulation imaging technique.

The coupled dynamics between quantum turbulence and normal-fluid turbulence is investigated via advanced numerical simulations. Our simulations show that quantum turbulence can be enhanced by normal-fluid turbulence through internal mutual friction.

Ion gating on the surface of the Mott insulator Ca₂RuO₄ induces the progression of metallisation into the bulk interior without the influence of the current flow.

A magnetic shape memory effect, easy magnetization axis switching accompanied by crystallographic axis conversion, has been discovered in a heavy electron system CeSb_₂.

This study shows electrons interact with chiral phonons via crystal angular momentum, revealing a new angular momentum transfer mechanism and advancing quantum dynamics understanding in chiral materials.

The superconducting diode effect is proposed for a three-terminal semiconductor double-quantum-dot device. This effect is considerably enhanced by the Dirac-point singularities in the superconducting phase space.

In bilayer materials, moiré patterns reduce the phonon velocity, thus reducing the overall thermal conductivity, with a characteristic temperature dependence, at low temperatures.

We discovered an anomalous quantum state in which electric conduction exhibits a gapped behavior exclusively in one direction, in the quantum limit of the BiSb alloy under strong magnetic fields.

The most neutron-deficient tin isotope of ⁹⁸Sn has been discovered beyond the double-magic nuclide ¹⁰⁰Sn. It is produced by the projectile fragmentation of a ¹²⁴Xe beam and identified in the BigRIPS separator.

Even in dense colloidal suspensions, where long-range hydrodynamic interactions are screened, near-field hydrodynamic interactions qualitatively influence the selection of kinetic pathways.

Using a heavy ion beam of ¹²C, researchers have observed a candidate of the double Gamow–Teller giant resonance (DGTGR)—a new nuclear excitation state, related to neutrinoless double beta decay.

A simple example of a higher-order topological phase, in which the symmetry decreases step-by-step from the bulk to the corner, is realized in a magnetic system with a pyrochlore structure and is characterized by a series of quantized Berry phases defined for the bulk, surface, and edge.

Our study examines the magnetic structure of the monoaxial chiral helimagnet Yb(Ni_1-xCu_x)₃Al₉, providing first direct evidence of the formation of chiral soliton lattice state.

This study presents an innovative method to address the problem of phase transitions in quantum annealing, resulting in an exponential speedup of the process.

Analysis of the two-component Ginzburg-Landau theory suggests that a conventional vortex is transformed into two fractional vortices with the topological nature of core-down and core-up merons at the twin boundary of a nematic superconductor.

This Journal of the Physical Society of Japan Special Topics edition explores how physics and machine learning complement each other and can solve unresolved problems in physics.

This study reviews existing research on the pressure-induced variation of magnetic properties of transition metal mono-pnictides like CrAS, MnP, and others, aiming to understand the unconventional superconductivity observed in CrAs and MnP.

This paper presents a unified theoretical description for the topological Hall effect, covering the entire region from strong- to weak-coupling, extending its picture beyond the Berry phase.

The realization of an excitonic insulator can help in the establishment of a new electronic state in condensed matter physics, one that has the potential to exhibit novel electric, magnetic, and optical responses beyond those of conventional materials.

This study presents the exact analytical expressions for gap ratio distribution, which is widely used to measure the chaoticity of quantum systems in many-body systems.

This paper introduces a QUBO model for traffic signal optimization on real-world maps. Using D-Wave quantum annealing and SUMO simulations, the model reduces vehicle waiting times, but underperforms classical solvers.

This study explores the implications of global inconsistency and ’t Hooft anomalies for analyzing quantum field theories, using simple quantum mechanical models to provide valuable insights into these complex phenomena.

Generative artificial intelligence (AI) has gained considerable attention in scientific fields. By embedding physical symmetry into AI before training, we created a faster and lighter model. Scaling improves the accuracy and unlocks the potential of physics research and applications.

This study adopts Bayesian inference using the replica exchange Monte Carlo method to accurately estimate thin-film properties from X-ray Laue oscillation data, enabling quantitative analysis and appropriate noise modeling.

Quantum states can be categorized as hyperuniform or multifractal based on electronic characteristics. This study demonstrates that bosonic quasicrystalline systems exhibit hyperuniform or multifractal quantum states.

Secure computation allows the manipulation of material data without exposing them, thereby offering an alternative to traditional open/closed data management. We recently reported the development of an application that performs Bayesian optimization using secure computation.

Careful measurements were conducted on the hexagonal magnet GdGa₂ to reveal the experimental signatures of ultrasmall spin cycloids and of a potential Néel-type skyrmion lattice phase induced by a magnetic field.

The development of a high-power, low-noise ultraviolet laser facilitates fast Rydberg excitation of single ytterbium atoms, which is a fundamental step towards achieving high-fidelity two-qubit gates.