6 papers
Riemannian geometric classification and emergent phenomena of magnetic textures
Koki Shinada, Naoto Nagaosa
We propose a new classification of magnetic textures from the viewpoint of differential geometry. Magnetic textures are conventionally classified into collinear, coplanar, and nonc…
Semiclassical Wave-Packet Dynamics in Phase-Space Geometry: Quantum Metric Effects
Luca Maranzana, Koki Shinada, Ying-Ming Xie +2
Quantum geometry governs a wide range of transport and optical phenomena in quantum materials. Recent works have explored analogue electromagnetism and gravity in terms of the quan…
Quantum geometric bounds for observables: Linear responses, Drude weight, and orbital magnetization
Koki Shinada, Naoto Nagaosa
The quantum geometric tensor (QGT) provides nontrivial bounds among physical quantities, as exemplified by the metric-curvature inequality. In this paper, we investigate various bo…
Thermodynamic formulation of the spin magnetic octupole moment in bulk crystals
Jun Åiké, Robert Peters, Koki Shinada
The discovery of unconventional antiferromagnets, such as altermagnets, has drawn significant attention to higher-rank magnetic multipoles, particularly magnetic octupoles. Despite…
Thermodynamic relations for the Cooper pair's momentum in helical superconductors
Koki Shinada, Robert Peters
Two thermodynamic relations are proposed for the exact measurement of the center-of-mass (COM) momentum of the Cooper pairs in helical superconductors. The first relation concerns…
Nonlinear Magnetoelectric Effect under Magnetic Octupole Order: Its Application to a -Wave Altermagnet and a Pyrochlore Lattice with All-In/All-Out Magnetic Order
Jun Åiké, Koki Shinada, Robert Peters
Extensive investigation has recently been conducted into a new class of antiferromagnetic order known as magnetic octupole order. However, the high rank of octupoles makes it diffi…