arXiv subjects

Kazuyuki Yoshimura

Publications and source records attributed to Kazuyuki Yoshimura.

6 recordsLinked to original sources

arXiv2021

Heat transport in nonlinear lattices free from the Umklapp process

We construct one-dimensional nonlinear lattices having the special property such that the Umklapp process vanishes and only the normal processes are included in the potential functions. These lattices have long-range quartic nonlinear and nearest neighbor harmonic interactions with/without harmonic on-site potential. We study heat transport in two cases of the lattices with and without harmonic on-site potential by non-equilibrium molecular dynamics simulation. It is shown that the ballistic heat transport occurs in both cases, i.e., the scaling law $κ\propto N$ holds between the thermal conductivity $κ$ and the lattice size $N$. This result directly validates Peierls's hypothesis that only the Umklapp processes can cause the thermal resistance while the normal one do not.

nlin.CD↗

arXiv2021

Construction of nonlinear lattice with potential symmetry for smooth propagation of discrete breather

We construct a nonlinear lattice that has a particular symmetry in its potential function consisting of long-range pairwise interactions. The symmetry enhances smooth propagation of discrete breathers, and it is defined by an invariance of the potential function with respect to a map acting on the complex normal mode coordinates. Condition of the symmetry is given by a set of algebraic equations with respect to coefficients of the pairwise interactions. We prove that the set of algebraic equations has a unique solution, and moreover we solve it explicitly. We present an explicit Hamiltonian for the symmetric lattice, which has coefficients given by the solution. We demonstrate that the present symmetric lattice is useful for numerically computing traveling discrete breathers in various lattices. We propose an algorithm using it.

nlin.PS↗

arXiv2014

Efficient optical path folding by using multiple total internal reflections in a microcavity

We propose using an asymmetric resonant microcavity for the efficient generation of an optical path that is much longer than the diameter of the cavity. The path is formed along a star polygonal periodic orbit within the cavity, which is stable and confined by total internal reflection. We fabricated a semiconductor device based on this idea with an average diameter of 0.3 mm, and achieved a path length of 2.79 mm experimentally.

physics.optics↗

arXiv2007

Phase reduction of stochastic limit cycle oscillators

We point out that the phase reduction of stochastic limit cycle oscillators has been done incorrectly in the literature. We present a correct phase reduction method for oscillators driven by weak external white Gaussian noises. Numerical evidence demonstrates that the present phase equation properly approximates the dynamics of the original full oscillator system.

nlin.AO↗

arXiv2007

Nonresonant entrainment of detuned oscillators induced by common external noise

We have found that a novel type of entrainment occurs in two nonidentical limit cycle oscillators subjected to a common external white Gaussian noise. This entrainment is anomalous in the sense that the two oscillators have different mean frequencies, where the difference is constant as the noise intensity increases, but their phases come to be locked for almost all the time. We present a theory and numerical evidence for this phenomenon.

nlin.CD↗

arXiv2007

Consistency in the driven butterfly

We study the consistency of the responses in the chaotic Lorenz model driven by chaotic and colored-noise signals. A measure is introduced for the consistency of the response in the system for repeated applications of the same drive signal, starting at different initial conditions of the response system. The convergence of responses is analyzed in dynamical phase space in terms of the local conditional Lyapunov exponent. The dependence of the local conditional Lyapunov exponent on drive signal, and the existence of multiple basins of consistency depending on strength of drive signal, are shown.

nlin.CD↗