Year2024

A New Method for Finding Bound States in the Continuum

This study presents a general theory for constructing potentials supporting bound states in the continuum, offering a method for identifying such states in real quantum systems.

Mathematical methods, classical and quantum physics, relativity, gravitation, numerical simulation, computational modeling

Nuclear physics

Understanding Non-Invertible Symmetries in Higher Dimensions Using Topological Defects

By constructing Kramers-Wannier-Wegner duality and Z₂ duality defects and deriving their crossing relations, this study presents the first examples of codimension one non-invertible symmetries in four-dimensional quantum field theories.

Theoretical Particle Physics

A Neural Thermometer for Predicting Phase Transitions of Unknown Systems

A novel convolutional neural network predicts phase transition temperatures from spin configurations without prior information about order parameters, paving the way for the discovery of new materials in condensed matter physics.

Measurement, instrumentation, and techniques

Statistical physics and thermodynamics

Pressure-Tuned Classical–Quantum Crossover in Magnetic Field-Induced Quantum Phase Transitions of a Triangular-Lattice Antiferromagnet

The correspondence principle states that as quantum numbers approach infinity, the nature of a system described by quantum mechanics should match that described by classical mechanics. Quantum phenomena, such as quantum superposition and quantum correlation, generally become unobservable when a system approaches this regime. Conversely, as quantum numbers decrease, classical descriptions give way to observable quantum effects. The external approach to classical–quantum crossover has attracted research interest. This study aims to demonstrate a method for achieving such control in materials.

Magnetic properties in condensed matter

Electron states in condensed matter

Cross-disciplinary physics and related areas of science and technology

Discovery of Light-Induced Mirror Symmetry Breaking

The authors discovered the light-induced mirror symmetry breaking, paving the way for controlling mirror symmetries via light and for realizing various phenomena utilizing the mirror symmetry breaking.

Dielectric, optical, and other properties in condensed matter

Electronic transport in condensed matter

The Mysterious Superconductivity of Sr₂RuO₄

Researchers review the recent advancements made towards solving the mysteries of the unconventional superconductivity of Sr₂RuO₄, analyzing recent experiments and theoretical models and proposing approaches to resolve current challenges.

Superconductivity

General Quasi-Joint Probabilities on Finite-State Quantum Systems

This study investigates the properties of general quasi-joint probability distributions in finite-state quantum systems, revealing the Kirkwood-Dirac distribution as among the most favorable. This highlights the importance of complex distributions in understanding quantum probability.

Mathematical methods, classical and quantum physics, relativity, gravitation, numerical simulation, computational modeling

Discovery of Unconventional Pressure-Induced Superconductivity in CrAs

A new study has discovered pressure-induced superconductivity in the helimagnet CrAs, originating in the vicinity of the helimagnetic ordering, representing the first example of superconductivity in Cr-based magnetic systems.

Superconductivity

Electronic transport in condensed matter

Unification of Spin Helicity in the Magnetic Skyrmion Lattice of EuNiGe₃

In the magnetic skyrmion lattice of non-centrosymmetric EuNiGe₃, the original magnetic helicity, determined by the antisymmetric exchange interaction, is reversed, resulting in a unified helicity.

Magnetic properties in condensed matter

Having a Good Friend around Makes Life Better

It is true that having a good friend around makes life better, and this idea is also true in the quantum world.

Cross-disciplinary physics and related areas of science and technology

Antiferromagnetism Induces Dissipationless Transverse Conductivity

An investigation using high-quality NbMnP crystals demonstrates that the anomalous Hall conductivity arising from antiferromagnetism is dissipationless, as expected from the intrinsic mechanism.

Electronic transport in condensed matter

Magnetic properties in condensed matter

Electronic structure and electrical properties of surfaces and nanostructures

d² Trimer and d³ Tetramer in a Pyrochlore Lattice

Based on the charge disproportionation of V³⁺ and V²⁺, the V³⁺(d²) trimers and V²⁺(d³) tetramers in the vanadium pyrochlore lattice of AlV₂O₄ are described by the orbitally-induced Peierls mechanism.

Dielectric, optical, and other properties in condensed matter

Electron states in condensed matter

Structural Rotation and Falsely Chiral Antiferromagnetism: A New Combination Generating Ferrotoroidic State

The ferrotoroidic state, an exotic state of matter with broken space inversion and time-reversal symmetries, was achieved by combining structural rotation and falsely chiral antiferromagnetism in PbMn₂Ni₆Te₃O₁₈.

Magnetic properties in condensed matter

Dielectric, optical, and other properties in condensed matter

Understanding Electronic Ordering and Cross Correlations with Multipole Representation

This study reviews the recent advancements in research of multipole representations for understanding electronic orderings and cross-correlations in materials and presents future research directions.

Magnetic properties in condensed matter

Evaluation of the Exchange Stiffness Constants of Itinerant Magnets from the First-Principles Calculations

Using first-principles calculations, we evaluated the exchange stiffness constants of ferromagnetic metals at finite temperatures. The constants can be used as parameters in the Landau–Lifshitz–Gilbert equation.

Electron states in condensed matter

Structure and mechanical and thermal properties in condensed matter

Microscopic Exploration of Electronic States in Nickelate Superconductors

The multilayered nickelates, La₃Ni₂O₇ and La₄Ni₃O₁₀ , were investigated using nuclear magnetic resonance (NMR) at ambient pressure. Metallic electronic states under the density wave order were observed microscopically for both compounds.

Magnetic properties in condensed matter

Superconductivity

Single-Crystal Growth of a Cuprate Superconductor with the Highest Critical Temperature

Millimeter-sized single crystals of a trilayer cuprate superconductor (Hg,Re)Ba₂Ca₂Cu₃O_8+δ that exhibits the highest superconducting transition temperature under ambient pressure, were grown reproducibly and safely.

Superconductivity

Solving a Stochastic Differential Equation is Solving a Mean-Field Quantum Spin System

The replica method maps matrix-valued geometric Brownian motion to a mean-field quantum spin system. This correspondence makes it possible to obtain an exact solution for matrix-valued geometric Brownian motion.

Statistical physics and thermodynamics

Mathematical methods, classical and quantum physics, relativity, gravitation, numerical simulation, computational modeling

Magnetic properties in condensed matter

Cooking in Salt for Ultra-Clean Superconductor UTe₂

A new crystal growth technique, the molten salt flux liquid transport method, was developed to produce high-quality single crystals of spin-triplet superconductor UTe₂. This method is promising for exploring the exotic superconductivity of other materials.

Superconductivity

Exploring Electronic States in BEDT-TTF Organic Superconductors

This review, published in the Journal of the Physical Society of Japan, provides a comprehensive summary of the electronic states observed in BEDT-TTF type organic superconductors, including metal-insulator transitions, Mottness transitions, non-Fermi liquids, quantum spin liquids, and Bose-Einstein condensation.

Superconductivity

Electronic transport in condensed matter

Magnetic properties in condensed matter

Conversion of Chiral Phonons into Magnons in Magnets

A new phenomenon involving the conversion of chiral phonons into magnons is theoretically predicted. The effective magnetic field induced by chiral phonons causes a change in the spin magnetization of magnets.

Electronic transport in condensed matter

Which is Moving?—Pinning Down the Origin of Fluctuations in Muon Spin Relaxation—

The study demonstrated that we can distinguish between the diffusion motion of the muon itself and the motion of the surrounding ions in muon spin relaxation.

Structure and mechanical and thermal properties in condensed matter

Cross-disciplinary physics and related areas of science and technology

Variety of Mechanically Induced Spin Currents in Rashba Systems

Various types of spin currents, including unconventional types, are generated in Rashba spin-orbit coupled systems by dynamic lattice distortions associated with, for example, surface acoustic waves.

Electronic transport in condensed matter

Magnetic properties in condensed matter

Structure and mechanical and thermal properties in condensed matter

What Determines the Sign of Spin Current? ~ Theoretical Study of Spin Seebeck Effect in Antiferromagnetic Insulators

We developed a microscopic theory for the spin Seebeck effect in antiferromagnets, that explains the sign reversal of the spin current at the spin-flop transition point and describes the sorts of dominant carriers.

Electronic transport in condensed matter

Quantum Mechanics of One-Dimensional Three-Body Contact Interactions

The quantum mechanical description of topologically nontrivial three-body contact interactions in one dimension is not well understood. This study explores the Hamiltonian description of these interactions using the path-integral formalism.

Mathematical methods, classical and quantum physics, relativity, gravitation, numerical simulation, computational modeling

Theoretical Particle Physics

Chiral Anomalies in Organic Dirac Semimetals

A three-dimensional massless Dirac fermion system exhibiting broken chiral symmetry was successfully realized in organic conductor α-(BEDT-TTF)₂I₃ under high pressures. Our study detected the chiral anomaly-induced negative magnetoresistance and planar Hall effects and opened new avenues for further advancements in the field.

Electronic transport in condensed matter

Relation between Mean-Field Theory and Atomic Structures in Chalcogenide Glasses

The authors conducted various of X-ray and neutron scattering experiments on typical chalcogenide glasses and clarified the relationship between the atomic structure and simple rigidity percolation theory.

Structure and mechanical and thermal properties in condensed matter

Thermodynamic Property of a CMOS Device beyond Landauer Limit

Focusing on a CMOS NAND GATE operating in a sub-threshold region, the thermodynamic cost of computation was analyzed in relation to input/output voltages surpassing the Landauer limit.

Statistical physics and thermodynamics

Electronic transport in condensed matter

Cross-disciplinary physics and related areas of science and technology

Investigating Unitarity Violation of Lee–Wick’s Complex Ghost with Quantum Field Theory

Theories with fourth-order derivatives like Lee–Wick’s quantum electrodynamics model or quadratic gravity result in complex ghosts above a definite energy threshold that violate unitarity.

Theoretical Particle Physics

Current Melt Frozen Electrons

The origin of the current-induced insulator-to-metal transition of samarium monosulfide was explained by the 4f−5d hybridization observed using optical reflectivity and photoelectron spectroscopies.

Dielectric, optical, and other properties in condensed matter

Magnetic properties in condensed matter

Towards Uncovering the Hidden Order of URu₂Si₂ Phase Transition

We propose a chiral charge as the hidden order parameter in URu₂Si₂ and present experiments to detect it by focusing on breakings of mirror and inversion symmetries at the local uranium ion.

Magnetic properties in condensed matter

Electronic structure and electrical properties of surfaces and nanostructures