A5052730300- Topological Materials and Phenomena
- Quantum and electron transport phenomena
- Quantum many-body systems
- Organic and Molecular Conductors Research
- Quantum chaos and dynamical systems
- Geomagnetism and Paleomagnetism Studies
- Photonic and Optical Devices
- Quantum Chromodynamics and Particle Interactions
- Rare-earth and actinide compounds
- Dynamics and Control of Mechanical Systems
- Quantum Information and Cryptography
- Intermetallics and Advanced Alloy Properties
- Elasticity and Wave Propagation
- Advanced Thermodynamics and Statistical Mechanics
- Spectroscopy and Quantum Chemical Studies
- Astro and Planetary Science
- Opinion Dynamics and Social Influence
- Advanced Algebra and Geometry
- Heusler alloys: electronic and magnetic properties
- Mechanical and Optical Resonators
- Quantum, superfluid, helium dynamics
- Graphene research and applications
- Molecular spectroscopy and chirality
- Molecular Junctions and Nanostructures
- Elasticity and Material Modeling
The University of Tokyo
2021-2025
We introduce two disorder-free variants of the Sachdev-Ye-Kitaev (SYK) model, demonstrate their integrability, and study static dynamical properties. Unlike diagrammatic techniques, integrability these models allows us to obtain correlation functions even when number Majorana fermions is finite. From solutions, we find that out-of-time-order correlators (OTOCs) in exhibit exponential growth at early times, resembling many-body quantum chaotic systems, such as those with disorder or external...
We investigate the orbital magnetic susceptibility of tight-binding model for honeycomb ladder with additional vertical hopping. Despite being one-dimensional, flux penetrating hexagonal rings affects energetics electrons, resulting in finite response. find that is sensitive to parameters as well chemical potential. At half-filling, response diamagnetic when system close pure ladder, whereas it turns paramagnetic two-leg ladder. also several characteristic properties away from such at band...
We examine the magnetic susceptibility of topological insulators microscopically and find that orbital-Zeeman (OZ) cross term, term between orbital effect spin Zeeman effect, is directly related to Berry curvature when z component conserved. In particular, OZ reflects Chern number, which results in quantization jump at phase transition. The magnitude units universal value 4|e|μB/h. also apply obtained formula an explicit model demonstrate quantization. For this model, physical origin...
An analytic approach to investigate the zero-temperature time evolution of Jaynes-Cummings system with cavity losses is developed. With realistic coupling between and environment assumed, a simple master equation derived, leading explicit solution for resonant case. This suitable analyses not only on single-excitation states but also many-excitation states, which enables us photon coherent state observe sharp collapses revivals under dissipation. For off-resonant case, other hand, present...
The anomalous spin transport coefficients of gapped Dirac electrons are studied with application to a quasi-two-dimensional organic conductor $α$-(BETS)$_2$I$_3$ in mind. In the presence gap induced by spin-orbit interaction, we show that effective Hamiltonian is similar model considered Kane and Mele additional tilting. With this Hamiltonian, conductivity tensors up linear order applied magnetic field obtained analytically using microscopic response theory or Kubo formula. It shown Hall...
We introduce two disorder-free variants of the Sachdev-Ye-Kitaev (SYK) model, demonstrate their integrability, and study static dynamical properties. Unlike diagrammatic techniques, integrability these models allows us to obtain correlation functions even when number Majorana fermions is finite. From solutions, we find that out-of-time-order correlators (OTOCs) in exhibit exponential growth at early times, resembling quantum chaotic systems such as those with disorder or external kick terms....
Recent experiments have established negative energetic elasticity, the contribution of energy to elastic modulus, as a universal property polymer gels. To reveal microscopic origin this phenomenon, Shirai and Sakumichi investigated model on cubic lattice with effect from solvent in finite-size calculations [Phys. Rev. Lett. 130, 148101 (2023)0031-900710.1103/PhysRevLett.130.148101]. Motivated by work, we provide simple platform study elasticity considering one-dimensional random walk effect....
Unconventional orbital paramagnetism without enhancement of the density states was recently discovered in nodal-line semimetal ZrSiS. Here, we propose a novel interband mechanism associated with negative curvature energy dispersions, which successfully explains observed anomalous paramagnetism. This arises from fluctuations along nodal line, inherent realistic materials. Our new indicates that such serves as strong evidence for existence lines not only ZrSiS but potentially various other...
In our previous publication [Ozaki and Ogata, Phys. Rev. Res. 3, 013058 (2021)], the quantization of orbital-Zeeman (OZ) cross term in magnetic susceptibility, or spin Zeeman orbital effect, was shown for Kane-Mele model using expansion around Dirac points. present study, we accurately evaluate orbital, spin-Zeeman, OZ a recently developed formulation. This method uses explicit real-space Bloch wave functions enables us to each contribution taking into account an infinite number high-energy...
This study investigates the electronic states and physical quantities of an organic charge-transfer complex HMTSF-TCNQ, which undergoes a charge-density-wave (CDW) phase transition at temperature $T_c\simeq 30$ K. A first-principles calculation is utilized to determine that normal state topological semimetal with open nodal lines. Besed on calculation, we develop tight-binding model investigate in detail. Below $T_c$, CDW examined scheme using mean-field approximation. It shown lines are...
In our previous publication [S. Ozaki and M. Ogata, Phys. Rev. Research 3, 013058], the quantization of orbital-Zeeman (OZ) cross term in magnetic susceptibility, or spin Zeeman orbital effect, was shown for Kane-Mele model using expansion around Dirac points. present study, we accurately evaluate orbital, spin-Zeeman, OZ a recently developed formulation. This formula is written terms explicit Bloch wave functions, enables us to each contribution taking account integration over whole...