arXiv subjects

Kaito Takahashi

Publications and source records attributed to Kaito Takahashi.

3 recordsLinked to original sources

arXiv2025

Unveiling Optimal Diffusion for Infection Control in Brownian Particle Systems

Understanding the spread of infectious diseases requires integrating movement, physical constraints, and spatial configurations into epidemiological models. In this study, we investigate how particle diffusivity, hardcore interactions, and non-equilibrium initial conditions influence infection dynamics within a system of Brownian particles. Using numerical simulations and theoretical analysis, we reveal a nontrivial relationship between diffusivity and the speed of infection spread. Specifically, when particles are initially positioned at uniform distances greater than the infection radius -- a non-equilibrium configuration -- there exists an optimal diffusion coefficient that minimizes the infection propagation speed. This counterintuitive result arises from the competition between diffusive timescales and the rate of infection transmission. The presence of an optimal diffusivity is observed both in systems with and without hardcore interactions, provided that the infection radius exceeds the mean lattice spacing. Our findings provide a theoretical framework for understanding and controlling the spread of infections in confined and diffusive environments, with potential implications for designing movement-based strategies for infection control.

cond-mat.other↗

arXiv2024

Native defects and their complexes in spinel LiGa5O8: the puzzle of p-type doping

Recently, LiGa$_5$O$_8$ was identified as a cubic spinel type ultra-wide-band-gap semiconductor with a gap of about 5.36 eV and reported to be unintentionally p-type. Here we present first-principles calculations of the native defects and various of their complexes to try to explain the occurrence of p-type doping. Although we find Li-vacancies to be somewhat shallower acceptors than in LiGaO$_2$, and becoming slightly shallower in complexes with donors such as V$_{\rm O}$ and Ga$_{\rm Li}$ antisites, these $V_{\rm Li}$ based defects are not sufficiently shallow to explain p-type doping. The dominant defects are donors and in equilibrium the Fermi level would be determined by compensation between donors and acceptors, and pinned deep in the gap.

cond-mat.mtrl-sci↗

arXiv2016

Information geometry of sandwiched Rényi $α$-divergence

Information geometrical structure $(g^{(D_α)}, \nabla^{(D_α)},\nabla^{(D_α)*})$ induced from the sandwiched Rényi $α$-divergence $D_α(ρ\|σ):=\frac{1}{α(α-1)}\log\,{\rm Tr} \left(σ^{\frac{1-α}{2α}}ρ\,σ^{\frac{1-α}{2α}}\right)^α$ on a finite quantum state space $\mathcal{S}$ is studied. It is shown that the Riemannian metric $g^{(D_α)}$ is monotone if and only if $α\in(-\infty, -1]\cup [\frac{1}{2},\infty)$, and that the quantum statistical manifold $({\mathcal{S}}, g^{(D_α)}, \nabla^{(D_α)},\nabla^{(D_α)*})$ is dually flat if and only if $α=1$.

quant-ph↗