JournalJPSJ

A Solvent Viscosity-dependent Thermoelectric Conversion Efficiency

We found a beautiful empirical rule (α ∝ η^-0.4) between the electrochemical Seebeck coefficient α for Fe²⁺/Fe³⁺ redox pair and viscosity coefficient η of the organic solvent.

Structure and mechanical and thermal properties in condensed matter

Nanospace-confined Helium Shows Four-dimensional Quantum Phase Transition (QPT)

Helium confined in a nanoporous material shows a four dimensional superfluid transition. This is a unique example of four dimensional critical phenomenon caused by strong quantum fluctuation.

Structure and mechanical and thermal properties in condensed matter

BKT Phase Transitions in Magnetic Systems: Formations of Narrow Stripes and Vortex–Antivortex Pairs in a Quasi-2D Ferromagnet K₂CuF₄

Cryogenic Lorentz transmission electron microscopy directly shows that vortex and antivortex pairs emerge in a quasi-two-dimensional ferromagnet K₂CuF₄. This work may reveal the nature of Berezinskii, Kosterlitz, and Thouless phase transition in a magnetic system.

Magnetic properties in condensed matter

Structure and mechanical and thermal properties in condensed matter

Cross-disciplinary physics and related areas of science and technology

Single-crystal NaAlSi Shows Unconventional Superconductivity

Interesting normal and superconducting states of NaAlSi, a topological nodal line semimetal, were revealed by the measurements using the single crystals grown by the self-flux method.

Superconductivity

Phase Transition and Its Universality Class for a Quantum Spin Chain

We numerically diagonalize the Dimer-Trimer (DT) model Hamiltonian around the SU(3) symmetric point. As a result, we discover the phase transition at this point which belongs to the Berezinskii-Kosterlitz-Thouless (BKT)-like universality class.

Statistical physics and thermodynamics

Magnetic properties in condensed matter

Splitting Walls: Interplay of Different Orders in Multiferroic Materials

We theoretically showed an intrinsic splitting instability of composite domain walls in multiferroic materials under field drive. This instability is a direct result of the coexistence of multiple orders in the system.

Magnetic properties in condensed matter

Statistical physics and thermodynamics

Random Numbers Can Help Solve Difficult Problems in Many-body Physics

Theorists review a random state vector-based description of quantum many-body systems which helps greatly reduce the computational burden involved in their numerical simulations, opening doors to applications in quantum computing.

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

Electronic transport in condensed matter

Magnetic properties in condensed matter

Hybrid Quantum–Classical Algorithms: At the Verge of Useful Quantum Computing

Scientists discuss the recent progress in algorithms that have enabled hybrid quantum–classical computers, which has brought the quest to realize useful quantum computing much closer to its finish line.

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

Cross-disciplinary physics and related areas of science and technology

Quantum Phase Transition in Spin Dimer Systems

A magnetic moment fluctuates in both longitudinal and transverse directions. The total moment sum rule is a conservation law that can help us resolve data of neutron scattering into the two components.

Magnetic properties in condensed matter

No Mass Gap Phase Transition in Novel Massless Dirac Fermion Material

Using an organic massless Dirac fermion system, we found that massless Dirac fermions undergo a quantum phase transition without creating any mass gap even in the strong coupling regime.

Electron states in condensed matter

Electronic transport in condensed matter

Of Spins and Atoms: Combining Rotations to Obtain Directed Motion

The coupling between surface acoustic waves and spin waves is shown to depend strongly on the angle between the acoustic wavevector and magnetization. For a particular angle, it completely vanishes in one direction, which enables a unidirectional generation of surface acoustic waves by a ferromagnetic resonance.

Magnetic properties in condensed matter

Electromagnetism, optics, acoustics, heat transfer, and classical and fluid mechanics

Reducing the Number of Tests Using Bayesian Inference to Identify Infected Patients in Group Testing

Group testing is a method of identifying infected patients by performing tests on a pool of specimens. Bayesian inference and a corresponding belief propagation (BP) algorithm are introduced to identify the infected patients in group testing.

Statistical physics and thermodynamics

Cross-disciplinary physics and related areas of science and technology

Exploring the Pseudogap in Cuprate Superconductors

Electronic nematic correlation, in which electronic degree of freedom breaks the crystal symmetry, was found to have a potential link to the origin of high-temperature superconductivity in cooper oxide materials.

Superconductivity

Under Pressure: Getting the Electronic State of Europium Ions to Changes

Scientists show how pressure and quantum phenomena interplay to alter Europium’s electronic states in a unique manner, opening doors to novel applications in spintronics and technology.

Magnetic properties in condensed matter

On and Off: The Physics Behind Photoswitchable Magnetic Octacyanometalates

We make a major breakthrough in understanding the photoswitchable magnetism in square-antiprismatic octacyanometalates. We reveal that the ``bidirectional” magnetism is accompanied by ``monodirectional electronics” to find a possibility of fabricating multifunctional magnetic devices.

Dielectric, optical, and other properties in condensed matter

Magnetic properties in condensed matter

How is Brownian Motion Affected by a Fluctuating Random Surface?

A researcher has developed a new theory to describe the Brownian motion of a small object that is confined in a fluctuating random surface.

Statistical physics and thermodynamics

Structure and mechanical and thermal properties in condensed matter

Taking a Better Look at Data to Predict Exceptional Materials

Instead of regression, the evaluation values to measure the degree of separation of the distributions of the target variable were studied and applied to the magneto crystallineanisotropy of Co/Fe films.

Cross-disciplinary physics and related areas of science and technology

Magnetic properties in condensed matter

Using Analogy to Understand Localization in Quantum Annealing

Localization may cause the inefficiency of quantum annealing. The constrained quantum annealing of graph coloring provides a new viewpoint to analyze localization phenomena in quantum annealing.

Statistical physics and thermodynamics

Solving Quantum Equations with Gauge Fields: How Explicit Integrators Based on a Bipartite Lattice and Affine Transformations Can Help

We proposed an explicit numerical integrator consisting of affine transformation pairs resulting from the checkerboard lattice for spatial discretization. It can efficiently solve time evolution equations that describe dynamical quantum phenomena under gauge fields, e.g., generation, motion, interaction of quantum vortices in superconductors or superfluids.

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

Superconductivity

Extending Machine Learning to Fermion–Boson Coupled Systems and Excited-State Calculations

We have demonstrated the power of machine learning in representing quantum many-body states accurately. We have extended the applicability of neural-network wave functions and shown their usefulness in fermion-boson-coupled systems and excited-state calculations.

Magnetic properties in condensed matter

Structure and mechanical and thermal properties in condensed matter

Review of Cutting-Edge Research on Iron Selenide Superconductors

Scientists review the incredible progress in our understanding of the superconducting properties of iron selenide and provide their own insights, taking us one step closer to revolutionizing energy and electronics.

Superconductivity

Cross-disciplinary physics and related areas of science and technology

Hydrogen Science: Exploring the Properties of our Universe’s Smallest Building Block

Reviews on the most recent advances in hydrogen science, including cutting-edge fundamental studies in condensed matter physics with hydrogen-containing materials.

Toward a Hydrogen Society: Harnessing the Power of the Smallest Element

Comprehensive curated reviews by researchers on the latest research in hydrogen-related applications, including proton conductors, superconductivity, electrochemistry with hydrides, and more.

Novel Material Shows Unconventional Superconductivity with Magnetic Order Under Pressure

Multiple superconductivity wad found in the novel spin-triplet superconductor UTe₂, which is called “Silicon of Quantum Computers”. A complicated spin-triplet state is realized as a consequence of spin degree of freedom. This result will lead to a new state of topological superconductivity.

Superconductivity

Magnetic properties in condensed matter

Multiple Superconducting Phases in UTe₂: A Complex Analogy to Superfluid Phases of ³He

In quantum liquids, large differences are observed owing to differences in quantum statistics. The physical properties of liquid ³He (Fermion) and ⁴He (Boson) are considerably different at low temperatures. After the discovery of superconductivity in electron (i.e., Fermion) systems, a similar pairing ordered state was expected for ³He. Remarkably, the observed ordered state of ³He was more surprising than expected, multiple superfluid phases in the T–P phase diagram. The origin of the multiple phases was attributed to ferromagnetic interactions in the p-wave symmetry state.

Superconductivity

Magnetic properties in condensed matter

Magnetic Responses of Majorana Kramers Pairs on Time-Reversal Invariant Topological Superconductors

We reveal magnetic degrees of freedom of Majorana fermions and find a new type of response that are distinct from those of conventional electrons.

Superconductivity

Electronic structure and electrical properties of surfaces and nanostructures

What Dictates Nonlinear Behavior in Strongly Correlated Insulators?

The nonlinear conduction (the deviation from Ohm's law) has been discovered universally in various correlated materials. This may be explained by the percolation conduction in disordered materials.

Electronic transport in condensed matter

Statistical physics and thermodynamics