Computation of the Kolmogorov-Sinai entropy using statistitical mechanics: Application of an exchange Monte Carlo method

We propose a method for computing the Kolmogorov-Sinai (KS) entropy of chaotic systems. In this method, the KS entropy is expressed as a statistical average over the canonical ensemble for a Hamiltonian with many ground states. This Hamiltonian is constructed directly from an evolution equation that exhibits chaotic dynamics. As an example, we compute the KS entropy for a chaotic repeller by evaluating the thermodynamic entropy of a system with many ground states.Comment: 7 page

Fluctuation-dissipation relations outside the linear response regime in a two-dimensional driven lattice gas along the direction transverse to the driving force

We performed numerical experiments on a two-dimensional driven lattice gas, which constitutes a simple stochastic nonequilibrium many-body model. In this model, focusing on the behavior along the direction transverse to the external driving force, we numerically measure transport coefficients and dynamical fluctuations outside the linear response regime far from equilibrium. Using these quantities, we find the validity of the Einstein relation, the Green-Kubo relation and the fluctuation-response relation.Comment: 4 pages, 5 figure

Effective temperature in nonequilibrium steady states of Langevin systems with a tilted periodic potential

We theoretically study Langevin systems with a tilted periodic potential. It has been known that the ratio $\Theta$ of the diffusion constant to the differential mobility is not equal to the temperature of the environment (multiplied by the Boltzmann constant), except in the linear response regime, where the fluctuation dissipation theorem holds. In order to elucidate the physical meaning of $\Theta$ far from equilibrium, we analyze a modulated system with a slowly varying potential. We derive a large scale description of the probability density for the modulated system by use of a perturbation method. The expressions we obtain show that $\Theta$ plays the role of the temperature in the large scale description of the system and that $\Theta$ can be determined directly in experiments, without measurements of the diffusion constant and the differential mobility

Mineralogy and petrology of chondrule in Ouallen (Tanezrouft) meteorite

A chondritic meteorite is found at the Sahara desert about 135 km WSW of Ouallen, Algeria in 1936. It contains various kinds of chondrules, up to 0.2-2 mm in diameter. Constituent minerals of chondrules are olivine, Ca-poor pyroxene, and those of matrix are olivine, Ca-poor pyroxene, Ca-rich pyroxene, troilite, chromite and kamacite. Glass fills the interstices of olivines and pyroxenes in chondrules. The average chemical compositions of olivine, Ca-poor pyroxene and Ca-rich pyroxene are Fa_, Wo_En_Fs_ and Wo_En_Fs_. The average Fe/(Fe+Mg) rations of olivine, Ca-poor and Ca-rich pyroxenes in the barred chondrule are similar to those of the host rock in Ouallen chondrite. There is a wide range of Fe/(Fe+Mg) rations of olivine, Ca-poor and Ca-rich pyroxenes. The boundary between chondrules and matrix is distinct. Based on the texture and olivine composition, the Ouallen chondritic meteorite belongs to L3 chondrite after Van Schmus and Wood\u27s classification (1967)

The law of action and reaction for the effective force in a nonequilibrium colloidal system

We study a nonequilibrium Langevin many-body system containing two 'test' particles and many 'background' particles. The test particles are spatially confined by a harmonic potential, and the background particles are driven by an external driving force. Employing numerical simulations of the model, we formulate an effective description of the two test particles in a nonequilibrium steady state. In particular, we investigate several different definitions of the effective force acting between the test particles. We find that the law of action and reaction does not hold for the total mechanical force exerted by the background particles, but that it does hold for the thermodynamic force defined operationally on the basis of an idea used to extend the first law of thermodynamics to nonequilibrium steady states.Comment: 13 page