Satoshi Yukawa

Nonequilibrium Microscopic Distribution of Thermal Current in Particle Systems (2009)

Yukawa, Satoshi, Shimada, Takashi, Ogushi, Fumiko, Ito, Nobuyasu

A nonequilibrium distribution function of microscopic thermal current is studied by a direct numerical simulation in a thermal conducting steady state of particle systems. Two characteristic...

Non-linear rheology of layered systems - a phase model approach (2007)

Yoshino, Hajime, Matsukawa, Hiroshi, Yukawa, Satoshi, Kawamura, Hikaru

We study non-linear rheology of a simple theoretical model developed to mimic layered systems such as lamellar structures under shear. In the present work we study a 2-dimensional version of the...

Positional order and diffusion processes in particle systems (2006)

Watanabe, Hiroshi, Yukawa, Satoshi, Ito, Nobuyasu

The relaxation of a nonequilibrium solid to a fluid is determined by observing the positional order parameter in Monte Carlo simulations, and discussed based on diffusion processes in the...

Divergent Thermal Conductivity in Three-dimensional Nonlinear lattices (2006)

Shiba, Hayato, Yukawa, Satoshi, Ito, Nobuyasu

Heat conduction in three-dimensional nonlinear lattices is investigated using a particle dynamics simulation. The system is a simple three-dimensional extension of the Fermi-Pasta-Ulam $\beta$...

Efficiency of rejection-free dynamic Monte Carlo methods for homogeneous spin models, hard disk systems, and hard sphere systems (2006)

Watanabe, Hiroshi, Yukawa, Satoshi, Novotny, M. A., Ito, Nobuyasu

We construct asymptotic arguments for the relative efficiency of rejection-free Monte Carlo (MC) methods compared to the standard MC method. We find that the efficiency is proportional to...

Positional Order and Diffusion Processes in Particle Systems (2006)

Watanabe, Hiroshi, Yukawa, Satoshi, Ito, Nobuyasu

Nonequilibrium behaviors of positional order are discussed based on diffusion processes in particle systems. With the cumulant expansion method up to the second order, we obtain a relation between...

Molecular-Dynamics Simulation of Vulcanian Eruption (2005)

Yukawa, Satoshi, Ito, Nobuyasu

Vulcanian explosive eruption, which is a nonlinear and nonequilibrium abrupt dynamics of magma-gas mixture, is modeled by a two-component Lennard-Jones particle system. Molecular-dynamics simulation...

Size-dispersity effects in two-dimensional melting (2005)

Watanabe, Hiroshi, Yukawa, Satoshi, Ito, Nobuyasu

In order to investigate the effect of size dispersity on two-dimensional melting transitions, hard-disk systems with equimolar bidispersity are studied by means of particle dynamics simulations. From...

The Second Law of Steady State Thermodynamics for Nonequilibrium Quantum Dynamics (2001)

Yukawa, Satoshi

The second law of ordinary thermodynamics and the second law of steady state thermodynamics, as proposed by Oono and Paniconi, are investigated from the microscopic point of view for the open quantum...

A Quantum Analogue of the Jarzynski Equality (2000)

Yukawa, Satoshi

A quantum analogue of the Jarzynski equality is constructed. This equality connects an ensemble average of exponentiated work with the Helmholtz free-energy difference in a nonequilibrium switching...

Simulational Study on Dimensionality-Dependence of Heat Conduction (2000)

Shimada, Takashi, Murakami, Teruyoshi, Yukawa, Satoshi, Saito, Keiji, Ito, Nobuyasu

Heat conduction phenomena are studied theoretically using computer simulation. The systems are crystal with nonlinear interaction, and fluid of hard-core particles. Quasi-one-dimensional system of...

Dissipation Enhanced Asymmetric Transport in Quantum Ratchets (1997)

Tatara, Gen, Kikuchi, Macoto, Yukawa, Satoshi, Matsukawa, Hiroshi

Quantum mechanical motion of a particle in a periodic asymmetric potential is studied theoretically at zero temperature. It is shown based on semi-classical approximation that the tunneling...

Quantum Ratchets (1997)

Yukawa, Satoshi, Kikuchi, Macoto, Tatara, Gen, Matsukawa, Hiroshi

The concept of thermal ratchets is extended to the system governed by quantum mechanics. We study a tight-binding model with an asymmetric periodic potential contacting with a heat bath under an...

Coupled Map Traffic Flow Simulator Based on Optimal Velocity Functions (1997)

Shin-ichi Tadaki, Macoto Kikuchi, Yuki Sugiyama, Satoshi Yukawa

. A coupled map tra#c flow model is introduced based on optimal velocity functions. The model can be simulated under open boundary conditions. It is able to bear a variety of noises as well. Noises...

Coupled-Map Modeling of One-Dimensional Traffic Flow (1994)

Yukawa, Satoshi, Kikuchi, Macoto

We propose a new model of one-dimensional traffic flow using a coupled map lattice. In the model, each vehicle is assigned a map and changes its velocity according to it. A single map is designed so...