Year2024

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